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Specification for 11kV And 33kV Overhead Lines of Unearthed Construction on Single and
Specification for 11kV and 33kV overhead power lines of unearthed construction employing AAAC Conductors, supported on single and “H” type wood pole supports.
3 ISSUE RECORD
This is a controlled document. All copies printed via the Intranet or photocopied will be deemed uncontrolled. Issue Date Issue No Author Amendment Details May 2007 1 L Campbell Initial Issue
4 ISSUE AUTHORITY
Author Owner Issue Authority
L Campbell Senior Project Engineer
A Graham Policy and Standards Section Head
C Woodman Engineering Services Manager ……………………………
5 REVIEW
This Specification will be subject to review following implementation and in any case no later than three years after publication.
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Specification for 11kV And 33kV Overhead Lines of Unearthed Construction on Single and
12.8 Line Conductors......................................................................................................32 12.8.1 Line jumpers ........................................................................................................32 12.8.2 Down Dropper Jumpers .......................................................................................32
12.9 Insulators and Conductor Fittings .........................................................................33
12.12 Conductor Design/Erection Sags and Tensions ....................................................35
12.13 Conductor Spacing and Clearances .......................................................................36 12.13.1 Minimum Height of Line Conductors..................................................................36 12.13.2 Summary of Statutory Ground Clearances ..........................................................36 12.13.3 Clearances to Obstacles .......................................................................................37 12.13.4 Clearances to other Power Lines..........................................................................37 12.13.5 Railway and Canal Crossings ..............................................................................37 12.13.6 Telecommunications Crossings ...........................................................................37 12.13.7 Road / Motorway Crossings.................................................................................37
12.14 Safety Signs and Number Plates ............................................................................38
Appendix 1 11KV Non Severe Weather Area 50mm2 AAAC “Hazel” Conductor (L10) .......45
Table 1- Support Types and Duties Table for 50mm2 “HAZEL” AAAC ................................46
Table 2- Conductor Design Table for 50mm² “HAZEL” AAAC ..............................................47
Table 3- Conductor Pre-Tension Table for 50mm2 “HAZEL” AAAC.....................................48
Table 4- Conductor Erection Table for 50mm2 “HAZEL” AAAC...........................................48
Table 5-Maximum Angle of Deviation for Single Poles for 50mm2 “HAZEL” AAAC...........49
Table 6-Maximum Angle of Deviation for “H” Poles for 50mm2 “HAZEL” AAAC .............49
Table 7-Strut Load in Single Poles with One or Two Stays (kgf) for 50mm2 “HAZEL” AAAC..........................................................................................................................................................50
Table 8-Strut Load in “H” Poles with Two or Three Stays (kgf) for 50mm2 “HAZEL” AAAC..........................................................................................................................................................51
Table 9- Strut Load in Single Pole Double Terminal Structures with Four Stays (kgf) for 50mm2 “HAZEL” AAAC..............................................................................................................52
Table 10-Strut Loading in Single Pole Construction Terminals (kgf) for 50mm2 “HAZEL” AAAC..............................................................................................................................................52
Table 11-Stayed Pole Strut Capabilities for 50mm2 “HAZEL” AAAC....................................53
Table 12-Pole Sizing for Single Pole Intermediate and Section Poles for 50mm2 “HAZEL” AAAC..............................................................................................................................................54
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Specification for 11kV And 33kV Overhead Lines of Unearthed Construction on Single and
Table 1- Support Types and Duties Table for 100mm2 “OAK” AAAC (Severe Weather Area)..........................................................................................................................................................56
Table 5-Maximum Angle of Deviation for Single Poles for 100mm2 “OAK” AAAC (Severe Weather Area)................................................................................................................................59
Table 6-Maximum Angle of Deviation for “H” Poles for 100mm2 “OAK” AAAC (Severe Weather Area)................................................................................................................................59
Table 7- Strut Load in Single Poles with One or Two Stays (kgf) for 100mm2 “OAK” AAAC (Severe Weather Area) ..................................................................................................................60
Table 8- Strut Load in “H” Poles with Three Stays (kgf) for 100mm2 “OAK” AAAC (Severe Weather Area)................................................................................................................................61
Table 8- Strut Load in “H” Poles with Three Stays (kgf) for 100mm2 “OAK” AAAC (Severe Weather Area) (Cont)....................................................................................................................62
Table 9– Strut Loading in Single Pole Construction Terminals (kgf) FOR 100mm2 “OAK” AAAC (Severe Weather Area)......................................................................................................62
Table 10-Stayed Pole Strut Capabilities for 100mm2 “OAK” AAAC (Severe Weather Area)..........................................................................................................................................................63
Table 10–Stayed Pole Strut Capabilities for 100mm2 “OAK” AAAC (Severe Weather Area) (cont.)...............................................................................................................................................64
Table 11- Pole Sizing for Single Pole Intermediate and Section Poles for 100mm2 “OAK” AAAC..............................................................................................................................................65
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Specification for 11kV And 33kV Overhead Lines of Unearthed Construction on Single and
Appendix 3 33kV Non Severe Weather Area 150mm2 AAAC “ASH” Conductor (L27) .......66
Table 1- Support Types and Duties Table for 150mm2 “ASH”AAAC (Non Severe Weather Area)................................................................................................................................................67
Table 2- Conductor Design Table for 150mm² “ASH” AAAC (Non Severe Weather Area) .68
Table 3- Conductor Pre-Tension Table for 150mm2 “ASH”AAAC (Non Severe Weather Area)................................................................................................................................................69
Table 4- Conductor Erection Table for 150mm2 “ASH”AAAC (Non Severe Weather Area)69
Table 5-Maximum Angle of Deviation for Single Poles for 150mm2 “ASH”AAAC (Non Severe Weather Area)....................................................................................................................70
Table 6-Maximum Angle of Deviation for “H” Poles for 150mm2 “ASH” AAAC (Non Severe Weather Area)................................................................................................................................70
Table 7-Strut Load in Single Poles with One or Two Stays (kgf) for 150mm2 “ASH”AAAC (Non Severe Weather Area) ..........................................................................................................71
Table 8-Strut Load in “H” Poles with Three Stays (kgf) for 150mm2 “ASH”AAAC (Non Severe Weather Area)....................................................................................................................72
Table-9 Strut Load in “H” Pole Structures with Four Stays (kgf) for 150mm2 “ASH”AAAC (Non Severe Weather Area) ..........................................................................................................73
Table 10– Strut Loading in Single Pole Construction Terminals (kgf) for 150mm2 “ASH”AAAC (Non Severe Weather Area) .................................................................................74
Table 11-Stayed Pole Strut Capabilities for 150mm2 “ASH”AAAC (Non Severe Weather Area)................................................................................................................................................75
Table 11– Stayed Pole Strut Capabilities for 150mm2 “ASH”AAAC (Non Severe Weather Area) (cont.)....................................................................................................................................76
Table 12-Pole Sizing for Single Pole Intermediate and Section Poles for 150mm2 “ASH”AAAC (Non Severe Weather Area) .................................................................................77
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Specification for 11kV And 33kV Overhead Lines of Unearthed Construction on Single and
Appendix 4 33kV Non Severe Weather Area.200mm2 AAAC “POPLAR” Conductor (L33)78
Table 1- Support Types and Duties Table for 200mm2 “POPLAR”AAAC (Non Severe Weather Area)................................................................................................................................79
Table 2- Conductor Design Table for 200mm² “POPLAR”AAAC (Non Severe Weather Area)................................................................................................................................................80
Table 3- Conductor Pre-Tension Table for 200mm2 “POPLAR”AAAC (Non Severe Weather Area)................................................................................................................................................81
Table 4- Conductor Erection Table for 200mm2 “POPLAR”AAAC (Non Severe Weather Area)................................................................................................................................................81
Table 5-Maximum Angle of Deviation for Single Poles for 200mm2 “POPLAR”AAAC (Non Severe Weather Area)....................................................................................................................82
Table 6-Maximum Angle of Deviation for “H” Poles for 200mm2 “POPLAR”AAAC (Non Severe Weather Area)....................................................................................................................82
Table 7-Strut Load in Single Poles with One or Two Stays (kgf) for 200mm2 “POPLAR”AAAC (Non Severe Weather Area) .........................................................................83
Table 8-Strut Load in “H” Poles with Three Stays (kgf) for 200mm2 “POPLAR”AAAC (Non Severe Weather Area)....................................................................................................................84
Table-9 Strut load in “H” Poles with Four Stays (kgf) for 200mm2 “POPLAR”AAAC (Non Severe Weather Area)....................................................................................................................85
Table 10– Strut Loading in Single Pole Construction Terminals (kgf) for 200mm2 “POPLAR”AAAC (Non Severe Weather Area) .........................................................................85
Table 11-Stayed Pole Strut Capabilities for 200mm2 “POPLAR”AAAC (Non Severe Weather Area)................................................................................................................................86
Table 11– Stayed Pole Strut Capabilities for 200mm2 “POPLAR”AAAC (Non Severe Weather Area) (cont.)....................................................................................................................87
Table 12-Pole Sizing for Intermediate and Section Poles for 200mm2 “POPLAR”AAAC (Non Severe Weather Area)....................................................................................................................88
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Specification for 11kV And 33kV Overhead Lines of Unearthed Construction on Single and
Appendix 5 33kV Severe Weather Area 200mm2 AAAC “POPLAR” Conductor (L33) .......89
Table 1- Support Types and Duties Table for 200mm2 “POPLAR”AAAC (Severe Weather Area)................................................................................................................................................90
Table 5-Maximum Angle of Deviation for Single Poles for 200mm2 “POPLAR”AAAC (Severe Weather Area) ..................................................................................................................93
Table 6-Maximum Angle of Deviation for “H” Poles for 200mm2 “POPLAR”AAAC (Severe Weather Area)................................................................................................................................93
Table 7-Strut Load in Single Poles with One or Two Stays (kgf) for 200mm2 “POPLAR”AAAC (Severe Weather Area) .................................................................................94
Table 8-Strut Load in “H” Poles with Three Stays (kgf) for 200mm2 “POPLAR”AAAC (Severe Weather Area) ..................................................................................................................95
Table 9-Strut Load in “H” Poles with Four Stays (kgf) for 200mm2“POPLAR”AAAC (Severe Weather Area) ..................................................................................................................96
Table 10–Strut Loading in Single Pole Construction Terminals (kgf) for 200mm2 “POPLAR”AAAC (Severe Weather Area) .................................................................................96
Table 11-Stayed Pole Strut Capabilities for 200mm2 “POPLAR” AAAC (Severe Weather Area)................................................................................................................................................97
Table 11–Stayed Pole Strut Capabilities for 200mm2 “POPLAR”AAAC (Severe Weather Area) (cont.)....................................................................................................................................98
Table 12-Pole Sizing for Single Pole Intermediate and Section Poles for 200mm2 “POPLAR”AAAC (Severe Weather Area) .................................................................................99
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Specification for 11kV And 33kV Overhead Lines of Unearthed Construction on Single and
Appendix 6 33kV Severe Weather Area 300mm2 AAAC “UPAS” Conductor (L35) ...........100
Table 1- Support Types and Duties Table for 300mm2 “UPAS”AAAC (Severe Weather Area)..............................................................................................................................................101
Table 5-Maximum Angle of Deviation for Single Poles for 300mm2 “UPAS”AAAC (Severe Weather Area)..............................................................................................................................104
Table 6-Maximum Angle of Deviation for “H” Poles for 300mm2 “UPAS”AAAC (Severe Weather Area)..............................................................................................................................104
Table 7-Strut Load in Single Poles with One or Two Stays (kgf) for 300mm2 “UPAS”AAAC (Severe Weather Area) ................................................................................................................105
Table 8-Strut Load in “H” Poles with Three Stays (kgf) for 300mm2 “UPAS”AAAC (Severe Weather Area)..............................................................................................................................106
Table 10–Strut Loading in Single Pole Construction Terminals (kgf) for 300mm2 “UPAS”AAAC (Severe Weather Area) .....................................................................................107
Table 11-Stayed Pole Strut Capabilities for 300mm2 “UPAS”AAAC (Severe Weather Area)........................................................................................................................................................108
Table 11–Stayed Pole Strut Capabilities for 300mm2 “UPAS”AAAC (Severe Weather Area) (cont.).............................................................................................................................................109
Table 12- Pole Sizing for Intermediate and section Poles for 300mm2 “UPAS”AAAC (Severe Weather Area)..............................................................................................................................110
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Specification for 11kV And 33kV Overhead Lines of Unearthed Construction on Single and
Drawings and Component Listings ............................................................................................141
Figure 1 11Kv Single Pole Member Drilling, Scarfing and Marking........................................................................................ 144
Figure 2 11Kv H Pole Member Drilling, Scarfing and Marking ............................................................................................... 145
Figure 3 33Kv Light Construction Single Pole Member Drilling, Scarfing and Marking ...................................................... 146
Figure 4 33Kv Light Construction H Pole Member Drilling, Scarfing and Marking.............................................................. 147
Figure 5 33Kv Heavy Construction Single Pole Member Drilling, Scarfing and Marking..................................................... 148
Figure 6 33Kv Heavy Construction H Pole Member Drilling, Scarfing and Marking ............................................................ 149
Figure 7 Delta H Pole Drilling Scarfing and Marking................................................................................................................ 150
Figure 8 Single Pole Intermediate or Pin Angle (Drawing SP2147473) .................................................................................... 151
Figure 9 Single Pole Intermediate or Pin Angle (Drawing SP4018552) .................................................................................... 153
Figure 10 “H” Pole Intermediate Long Span (Drawing SP4019155) ........................................................................................ 155
Figure 11 Single Pole Straight Line or Angle Section (Drawing SP2147476)........................................................................... 157
Figure 12 Single Pole Straight Line or Angle Section (Drawing SP4018548)........................................................................... 159
Figure 13 “H” Pole Straight Line or Angle Section (Drawing SP4019003) .............................................................................. 161
Figure 14 Long Span “H” Pole Straight Line or Angle Section (Drawing SP2147486)........................................................... 163
Figure 15 Delta “H” Pole Section or Section Angle (Drawing SP2059611) .............................................................................. 165
Figure 16 Delta Long Span “H” Pole Section or Section Angle (Drawing SP2059372) ........................................................... 167
Figure 17 Single Pole Terminal (Drawing SP2147474)............................................................................................................... 169
Figure 18 “H” Pole Terminal (Drawing 2147485)....................................................................................................................... 171
Figure 19 Single Pole Double Terminal (Drawing SP4000578) ................................................................................................. 173
Figure 20 General Arrangement Intermediate Crossarm (Drawing SP4018402).................................................................... 175
Figure 21 General Arrangement Section Crossarm (Drawing SP4018433) ............................................................................. 176
Figure 22 General Arrangement Terminal Crossarm (Drawing SP4018401).......................................................................... 177
Figure 23 General Arrangement Long Span Crossarm (Drawing SP4017663) ....................................................................... 178
Figure 24 General Arrangement Crossarm Strut (Drawing SP4017649) ................................................................................. 179
Figure 25 General Arrangement Long Crossarm Strut (Drawing SP4017635) ....................................................................... 180
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Specification for 11kV And 33kV Overhead Lines of Unearthed Construction on Single and
Figure 53 General Arrangement Single Pole Bog Shoe (Drawing SP2146665) ........................................................................ 208
Figure 54 General Arrangement “H” Pole Bog Shoe (Drawing SP........................................................................................... 209
Figure 55 General Arrangement Bog Shoe Strut (Drawing SP2146662) .................................................................................. 210
Figure 56 General Arrangement 300 Angle Bracket................................................................................................................... 211
Figure 57 General Arrangement Wind Stay Attachment .......................................................................................................... 212
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Specification for 11kV And 33kV Overhead Lines of Unearthed Construction on Single and
For the purpose of this Specification the following definitions apply: AAAC : All Aluminium Alloy Conductor. Approvals Engineer: Energy Networks representative appointed by the Engineering
Services Manager with authority for Energy Networks approvals.
Approved: Equipment approved in accordance with Energy Networks’
Equipment Approvals Procedure, and which is considered suitable for installation on The Company’s networks.
Auxiliary Equipment: Equipment other than that forming part of the line design
which may be placed on supports such as transformers, fuse gear etc.
Average Span: The arithmetic average of a number of spans in a line or
section of line. Basic Span: The span length adopted for sag/tension calculations. Conductor Creep: Permanent long term elongation of the conductor. Conductor Downpull: The vertical loading imposed by the conductors corresponding
to a gradient measured between adjacent pole tops. Construction Terminal: A support at which the line may be terminated temporarily on
one side of the Crossarm only on tension insulator sets. Crossarm Assembly: A descriptive term used to include all pole top Crossarm
components and fixings. Energy Networks: SP SP Power Systems Ltd, operator of network assets on
behalf of the company. Engineer: Energy Networks’ nominated representative having authority
over technical matters contained in this specification. Intermediate Support: A support in a straight run of line on which the conductors are
supported on pin or post Insulators. Maximum Conductor Weight (MCW): The likely maximum vertical component of
applied conductor load.
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Specification for 11kV And 33kV Overhead Lines of Unearthed Construction on Single and
When designing or constructing overhead lines in accordance with this specification it is essential that the appropriate persons be in possession of the latest versions of the following documents. Statutory Legislation ESQCR Electricity Safety, Quality and Continuity Regulations 2002 SI 2665 NRSWA The New Road and Street Works Act 1991 British Standards (BS) BS 144 Specification for coal tar creosotes for wood preservation. BS 183 Specification for General Purpose Galvanised Steel Wire Strand BS EN ISO 898-1 Mechanical properties of fasteners made of carbon steel and alloy steel,
Bolts, Screws and Studs. BS EN ISO 1461 Hot dip galvanised coatings on fabricated iron and steel articles BS 1494-1 Fixings for Sheet, Roof and Wall Coverings BS 1990 Part 1 Wood poles for overhead lines (Power and Telecom’s. lines). BS 3288 Insulator and conductor fittings for overhead power lines. BS 4102 Steel Wire for General Fencing Purposes BS 5950 Part 1 Structural Use of Steelwork in building. – Code of Practice BS EN 20898-1 Mechanical Properties of Fasteners – Bolts, Screws and Studs BS EN 10244-2 Non-ferrous metallic coatings on steel wire - Part 2: Zinc or zinc alloy
coatings on steel wire. BS EN 61284 Overhead Lines-Requirements and Tests for Fittings. Continued on next page….
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Specification for 11kV And 33kV Overhead Lines of Unearthed Construction on Single and
Continued from previous page…. Energy Networks Documents EPS-01-004 Policy for Signing and Guarding of Electrical Networks Apparatus. OHL-14-005 Wood Pole Overhead line Clearances. OHL-03-095 Specification for Overhead Line Conductor. OHL-03-096 Specification for Overhead Line Conductor Incorporating Optical Fibres. DOC-00-313 Wood Pole Overhead Line Manual.
OHL-18-017 Termination of 11kV Cables on Single Poles. OHL-18-018 Termination of 11kV Cables on “H” Poles. OHL-18-019 Termination of 33kV Cables on a Crucifix. OHL-18-022 Erection of Optical Phase Conductors. OHL-21-003 Power Installed Screw Anchors (Sheer Pine Method). OHL-21-004 Power Installed Screw Anchors (Torque Method). OHL-21-016 Rock Anchors. OHL-22-003 Transformer Erection Single Bolt Fixing. OHL-22-004 Transformer Erection Single Pole Platform. OHL-22-005 Transformer Erection H Pole (2 Tirfor Method). OHL-22-010 Installation of Air Break Switch Disconnector. OHL-22-012 Installation of Novexia Auguste Switch. OHL-22-013 Installation of Pole Mounted Auto Reclosers. OHL-22-023 Installation of 15kV Trisec Air Break Sectionalisers. OHL-22-026 Installation of 11kV Fuse Mounts on Single Poles. OHL-22-027 Installation of 11kV Fuse Mounts With Outrigger Brackets. OHL-22-028 Installation of 11kV Fuse Mounts on Spur Poles. OHL-22-029 Installation of 11kV Fuse Mounts on “H” Poles. OHL-22-030 Transformer Erection H Pole (1 Tirfor Method). OHL-23-001 Labelling of Wood Pole Apparatus in SP Distribution Ltd
Network Area & SP Transmission Ltd Network Area. OHL-23-002 Labelling of Wood Pole Apparatus in SP Manweb plc
Continued from previous page…. Electricity Association Technical Specifications (ENATS) ENATS 43-8 Overhead Line Clearances ENATS 43-40 Specification for Single Circuit Overhead Lines on Wood Poles for use at
High Voltage Up To and including 33kV. ENATS 43-88 Selection and treatment of wood poles and associated timber for overhead lines. ENATS 43-90 Anti-Climbing Devices and Safety Signs for HV Lines up to and including
400kV. ENATS 43-91 Stay strands and stay fittings for overhead lines. ENATS 43-92 Overhead Line Fittings. ENATS 43-93 Line Insulators. ENATS 43-95 Steelwork for overhead lines. ENATS 43-96 Fasteners and washers for wood pole overhead lines. ENATS 43-119 Designs and Use of Temporary Scaffold Guards Electricity Networks Association Engineering Recommendations (ER) ER-P27 Current Rating Guide for High Voltage Overhead Lines Operating In the
UK Distribution System. ER-PO5 Protection of Telecommunication Lines from High Voltage Power Lines.
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Specification for 11kV And 33kV Overhead Lines of Unearthed Construction on Single and
It is Asset Strategy’s aspiration that all Overhead networks will be suitably storm resilient, lines constructed to this specification will fulfil those requirements providing reliable and economical network performance. This Specification has been prepared to provide a design of 11kV and 33kV overhead lines suitable for application within the companies licensed areas. They incorporate features of previously proven company specifications, particularly with regard to conductors, maximum working tensions, span lengths and factors of safety. All overhead lines erected after 31st January 2003 are required to comply with the Electricity Safety, Quality and Continuity Regulations. Overhead lines designed and constructed in accordance with this Specification are deemed to comply with ESQCR 2002 SI 2665. Any overhead line or part of an overhead line, not complying with this Specification shall, in each case, be subject to Approval by the Engineering Services Manager or nominated representative. Approval will normally be sought when the line is being planned.
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Specification for 11kV And 33kV Overhead Lines of Unearthed Construction on Single and
The design basis for this specification mirrors that in ENA TS 43-40, utilising an empirical approach.
10.2 Conductors
The tension of any line conductor at a temperature of -5.6º Celsius and subjected to a design wind and ice loading appropriate to the environment in which the line will be situated, shall ensure that the conductor will have a minimum factor of safety of 2.5 over the rated breaking strength of the conductor. The basic span length is specific to the conductor and environment in which the line will be situated and will be specified in the relevant appendix.
10.3 Crossarms
The minimum factor of safety on all Crossarm assemblies and associated steelwork is 2.5 in a Non Severe Weather Environment and up to 3.5 in a Severe Weather Environment on the yield stress of the steel.
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Specification for 11kV And 33kV Overhead Lines of Unearthed Construction on Single and
The strength of supports is derived from formulae contained in BS 1990 part 1. The stresses created in intermediate supports are bending stresses due to windage on conductors, the loading point being 230mm above pole tops. All “in-line” intermediate and section poles have a minimum factor of safety of 3.5 in all Weather Environments. The stresses created in stayed supports are crippling stresses due to stay tension, steelwork and vertical conductor loads acting at the pole top. All angle and terminal poles have a minimum factor of safety of 2.5 in a Non Severe Weather Environment and up to 3.5 in a Severe Weather Environment.
Pole top horizontal loading has also to be maintained within specified limits to prevent pole top splitting. Poles shall be of a sufficient diameter to withstand the above-mentioned stresses. Therefore the minimum pole grade allowable in Appendix 1 only shall be “Medium”, all other Appendices require a minimum pole grade of “Stout” to BS 1990 Part 1 for the purpose of this Specification. In addition a minimum pole top diameter is specified in Table 11 of appendix 1 or Table 10 in all other appendices, this pole top diameter may exceed the minimum pole top diameter quoted in BS 1990 Part 1. This more onerous requirement should be taken into account when selecting poles. For Pinus Sylvestris, the average ultimate extreme fibre stress value used is in all pole calculations is 53.3N/mm².the average modulus of elasticity fibre stress is 10054N/mm². In all cases, the appropriate pole strength has been calculated using a maximum taper of 11.25mm/m.
10.5 Stays
The minimum factor of safety on stay assemblies is 2.5 in a Non Severe Weather Environment and up to 3.5 in a Severe Weather Environment based on the minimum failing load of the assembly.
11 MATERIALS
Except where otherwise specified all materials used in the construction of lines to this Specification shall comply with current British Standards and ENA Technical Specifications as appropriate. Only Energy Networks Approved materials shall be used.
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Specification for 11kV And 33kV Overhead Lines of Unearthed Construction on Single and
12 TECHNICAL REQUIREMENTS FOR THE ERECTION OF LINES
12.1 Structure Type and Capabilities
Table 1 of appendices 1 to 6 contained within this specification provides details of the various structure types, limiting span length and angle of deviation detailed under gradient conditions as applicable, together with the appropriate Energy Networks drawing reference numbers. The maximum span lengths indicated take account of conductor clashing and steelwork strength limitations. Poles, which are subject to Uplift at –5.6ºC, shall be sectioned.
12.2 Wood Poles
Wooden poles shall be of the species Scots Pine (Pinus Sylvestris) and shall be imported from a Nordic Country and grown at latitude greater than 60°00'00"N. Poles shall be creosoted to BS144 using the Rueping empty cell process. In all circumstances poles shall comply with BS 1990 Part 1 and ENATS 43-88 Parts 1 and 2. They shall be supplied drilled and scarfed. Pole blocks shall be fabricated to ENATS 43-91 drawing 439103 Type 2 and drawing 439112 Type 1 & 2 as required.
12.2.1 Section, Section Angle and Terminal Supports
The gradient limitations quoted in Table 1 of appendices 1 to 6 are derived from the conductor vertical load, which can be accommodated by the Crossarms and is expressed as a Downpull gradient, which is measured between adjacent pole tops. The gradient limitations quoted in Table 1 refer to Downpull gradients on each side of the support and therefore it is acceptable to summate gradients. The gradients limitations quoted in Table 1 are therefore permitted on both sides of the supports. Terminal supports are designed to allow for the appropriate value on one side of the structure only. The Uplift limits on section, section angle and terminal structures shall be taken as being the same as for Downpull detailed in Table 1 of the relevant appendices.
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Specification for 11kV And 33kV Overhead Lines of Unearthed Construction on Single and
For Section and intermediate structures the maximum Downpull shall be no greater than an equivalent gradient of 1:10 to the horizontal plane on either side of the structure.
For hillside applications, the maximum gradient quoted in Table 1 of appendices 1 to 6 for intermediate supports is limited by the method of conductor attachment and is permitted only where angle α ≥ 1660 and where angle β ≤ 1910 where these limitations cannot be satisfied a section structure should be employed.
For Terminal structures the maximum Downpull shall be equivalent to a gradient of 1:5 to the horizontal plane on one side of the structure only. Any structure not complying with the requirements set out above shall be subject to approval. Approval will normally be sought when the line is being planned.
1:4
β ≤ 1910
α ≥ 1660
1:10* 1:10*
β ≤ 1910
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Specification for 11kV And 33kV Overhead Lines of Unearthed Construction on Single and
The strut loading imposed on poles due to vertical components of stay and conductor tensions including any auxiliary equipment at specified angles of line deviation and ground slope conditions are specified in the Tables 7, 8 & 9 of appendices 1 to 6. For all single pole 11kV structures an allowance of 600kg has been included for the attachment of auxiliary equipment. During construction, section poles may be utilised as temporary terminals. Where a single pole section structure is required for this situation, the pole must be graded such that it is capable of a terminal load condition as detailed in pole strut loading tables of the relevant appendices. Temporary terminal stays will be fitted in accordance with Energy Networks Approved staying methods and placed at the ends of the crossarm and the stay anchors positioned no closer to the pole than two pole lengths, this may require to be increased significantly where conductors in excess of 100mm2 are employed to limit the loading applied to the pole and crossarm assembly.
12.4 Windspan and Foundation Requirements
Pole foundations shall be designed to withstand the overturning moment due to windage on conductors, poles and insulators. Foundation design shall also take account of the rupturing capacity of the ground. In excavating foundation holes, the minimum amount of soil shall be disturbed in order to take advantage of the load bearing value of the virgin ground as far as possible. Back-filled soil shall be compacted using hand or mechanical compaction methods, not more than 150mm of loose soil shall be returned between each ramming operation. All structures shall have a minimum of one foundation block fitted at a minimum of 500mm below ground level. Where an angle of deviation exists the top foundation block shall be on the inside of the angle. Where the quality of backfill material is unsuitable it will be necessary to replace the excavated material with a suitable imported backfill, however an Energy Networks approved soil additive, e.g. Permasoil, may be used to improve the quality of poor soil.
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Specification for 11kV And 33kV Overhead Lines of Unearthed Construction on Single and
The Engineer shall inspect holes and, where deemed necessary, additional kicking blocks or bog shoes as detailed in Energy Networks Drawings Reference SP2146665 (Single Pole Bog Shoe) or SP2146682 H Pole Bog Shoe shall be installed. In addition it may be necessary to install wind stays in accordance with Energy Networks Drawing Reference SP4000336 to exposed sections of line where directed by the Engineer. All Foundations shall have a minimum factor of safety of 2.5 in a Non Severe Weather Environment and up to 3.5 in a Severe Weather Environment. The values for Windspan capabilities for Unstayed Intermediate and Section structures quoted in Table 11 or 12 as applicable of the appendices have been calculated using a soil bearing capacity of 314 (kN/m²) Table 10 of appendix 1 and Table 11 of appendices 2 to 6 also detail the planting depths appropriate to the various pole lengths.
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Specification for 11kV And 33kV Overhead Lines of Unearthed Construction on Single and
All lines shall include supports, designed to contain a cascade failure, separated by not more than 1000m. Supports, which are considered adequate to provide failure containment, are: -
(i) Any Section Structure. (Minimum Grade Stout as defined in BS 1990)
(ii) Any H Pole Section Structure.
(iii) Any section angle structure, which requires to be fitted with twin-splayed, stays,
with a stay slope of 45°.
(iv) Any “H” Pole section angle structure in excess of 30o fitted with splayed stays with a stay slope of 45°.
(v) Any “H” Pole section, section angle structure fitted with twin splayed stays with a
stay slope of 45o employed on both sides of the structure in the plane of the line.
(vi) A Terminal Structure.
Conductor Acceptable Failure Containment Options
(i) (ii) (iii) (iv) (v) (vi)
Hazel √ √ √ √ √ √
Oak -- √ √ √ √ √
Ash -- √ √ √ √ √
Poplar -- -- √ √ √ √
Upas -- -- -- √ √ √
Note:- The following table indicates the minimum requirements to satisfy option (iv) for the various conductor types.
Conductor Type Angle of deviation on a Single Pole
Hazel >45o Oak >40o Ash >29o Poplar >15o
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Specification for 11kV And 33kV Overhead Lines of Unearthed Construction on Single and
The steelwork for the structure types included in this Specification has been designed using BS 5950 Part 1 and shall generally conform to the requirements of ENATS 43-95. All intermediate, section, section angle and terminal supports shall have anti-split bolts fitted above and below the Crossarm steelwork. Bolts shall generally conform to ENATS 43-96 and BS EN ISO 898-1 Terminal Bracing Straps Drawing reference SP4020576 for L33 construction and Drawing Reference SP4015138 for L35 or L36 construction shall be substituted for item 9 in the “H” Pole Terminal Structure general assembly Drawing reference SP2147485. M20 High Yield Steel Pole Bolts (Stamped 8.8) are required for all structures for all applications.
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Specification for 11kV And 33kV Overhead Lines of Unearthed Construction on Single and
Stays shall be Energy Networks Approved and comply with ENATS 43-91, design calculations have been based on galvanised steel stranding of 7/4.00mm, Grade 1150 to BS 183. Stay wires shall generally be made off with helical fittings at the pole top, insulator positions and on the stay rods. Where conductors in excess of 200mm2 are employed, Stay attachment at pole tops shall be as shown in Energy Networks Drawing ref SP4009862 Thimbles used for making off stay wire to stay rods shall conform to ENATS 43-91. Drawing 439109 Type 1 for 7 /4.00mm stays Stay blocks shall be cut from sawn timber to produce rectangular sections and shall conform to ENATS 43-91 as shown in Energy Networks Drawing ref SP4010920 for 7/4.00mm stays and shall be creosoted to BS 144 using the Rueping Empty Cell Process. Stay rods shall be adjustable and in accordance with ENATS 43-91 drawing 439101 Type 2 for 7/4.00mm stays. Tables 7 and 8 of the appendices detail the maximum angles of deviation allowable for the varying stay slopes relative to a number of stays. Terminal supports shall be stayed in accordance with the requirements for a 60º angle of deviation. Where two stays are required, they can be installed either splayed or in tandem. When splayed, they shall be a minimum of 3m apart at ground level. When in tandem, the stay blocks shall be in separate holes with at least 3m undisturbed ground between them. Tandem Stays are not permitted when the structure is designated as a failure containment structure as defined in 11.5 All stays are to be installed such that the stay wire is left tight under normal working conditions, with the stay load equally proportioned between the stays where multiple stays are employed. Stay insulators shall be as detailed with ENATS 43-91 drawing 439101 Type 1 for use at 11kV and for 33kV two Type 2 insulators in an insulator link assembly drawing 439108 shall be used. Insulators shall be inserted in every stay wire in such a position that, with the stay hanging down in a vertical position, the insulator shall be below the lowest bare conductor but in no circumstance less than 3m above ground. On multiple stayed poles, insulators shall be staggered to avoid clashing. The method of installation of stays is detailed in Energy Networks Document OHL-21-002 Rock stays and their method of installation will be of an Energy Networks Approved type the method of installation is detailed in as detailed in Energy Networks Document OHL-21-016.
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Only Energy Networks Approved power installed screw anchors may be used and may only be installed with the agreement of the Engineer The method of installation is detailed in Energy Networks Document’s OHL-21-003 & OHL-21-004.
12.8 Line Conductors
The line conductors shall conform to Energy Networks Specification for Overhead Line Conductor (OHL-03-095) or (OHL-03-096) as applicable. The use of PVC covered conductor for line conductor applications is not recommended and reference should be made to the Engineering Services Manager when considering any use of covered conductors.
12.8.1 Line jumpers
Line jumpers on section and tapping poles shall be formed in the same AAAC Conductor as the line conductors. These jumpers shall be directly connected to the line conductor by Energy Networks Approved Compression connectors.
12.8.2 Down Dropper Jumpers
Where there is a requirement to connect an item of 11kV plant or apparatus to the overhead line, the associated connecting jumpers shall be formed in covered copper flexible jumpers. These jumpers shall not be connected to the overhead line conductor directly, a pre fabricated Energy Networks approved wedge type live line bail shall be connected to the overhead line conductor, the flexible jumper shall then be connected to the live line bail using a Energy Networks Approved flexible jumper kit. The method of installation of down dropper jumpers is detailed in Energy Networks Document OHL-22-006.
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Only Energy Networks Approved polymeric tension insulator sets shall be used at section and terminal positions, these shall comply with ENATS 43-93. Where the conductors cross sectional area is in excess of 200mm2 the tension string crossarm attachment components shall comprise of a BS3288 Shackle Ref 28/29 and a BS 3288 Ball End Link Ref 28/30. These components shall be substituted for item 15 of the structure general assembly drawings. All components in the tension string including the tension insulator shall be rated at a minimum value of 125kN. Where required Sag Adjuster Plates BS3288 Ref 28/100 and an additional BS3288 Shackle Ref 28/29 may be installed as shown in Appendix 7 in Energy Networks Drawing Ref SP4022218 For non-tension insulators, only Energy Networks Approved Porcelain Insulators shall be used on intermediate structures, and for conductor support, unless otherwise specified. These shall comply with ENATS 43-93, Drawing Reference 439301 for 11kV and Drawing Reference 439302 for 33kV. Where the conductor cross sectional area is in excess of 200mm2 only Energy Networks approved polymeric post type insulators complying with ENATS 43-93 with a separate armour grip suspension clamp top complying with BS EN 61284 shall provide support at intermediate structures. These may also be employed as support insulators at terminal and section structures. These post insulators shall be substituted for items 11 & 12 of the structure general assembly drawings. At Earthed Poles Energy Networks Approved Polymeric Insulators shall be used for all line insulation applications. All Insulator and Conductor fittings shall comply with BS 3288. Arcing horns shall not normally be fitted to tension insulator sets. Energy Networks Approved Tension dead-ends can be either of the compression or helical type depending on the conductor type. These shall meet the requirements of ENATS 43-92. Full tension mid-span joints shall only be used in exceptional circumstances when agreed by the Engineer and any such joint shall be located at least 1 metre from any conductor dead-end, or conductor fitting. Non-tension joints shall be of the compression type meeting the requirements of ENATS 43-92.
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Specification for 11kV And 33kV Overhead Lines of Unearthed Construction on Single and
The basic span length adopted by this specification is dependant on the chosen conductor and the environment in which the line will be situated and as such is specified in the appropriate conductor appendices. Individual spans will normally be within ± 20% of the chosen basic span. The average span length of every kilometre of line (not necessarily between section supports) shall not be greater than the basic span. In extreme circumstances an occasional Maximum span shall be permitted. In such cases the maximum span length for individual structures is given in Table 1 of appendices 1 to 6. No more than two adjacent maximum spans shall be permitted as detailed in Table 1 of appendices 1 to 6 Where Long Span “H” Pole Structures are employed, in line stays shall be installed against the long spans to reduce the effect of out of balance tensions on the adjacent spans.
12.11 Section Lengths
Section lengths, defined as the length between two section supports, shall not exceed 1000m.
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Ordinates for plotting uplift curves are based on conductor design tensions. Ordinates for plotting ground clearance curves assume the use of new conductor and include an allowance for long-term creep over a period of 25 years. Conductor design sags / tensions are given in Table 2 of appendices 1 to 6. Erection sags and tensions are given in Table 4 of appendices 1 to 6 and are based on the conductor design tensions, but have been subject to a 10% over tension to accommodate the long-term stretch of the conductor during the life of the line. The conductors shall be pre-tensioned for a minimum time of 60 minutes. At 15-minute intervals during this period, the tension or sag shall be adjusted in order to maintain the correct value. Conductor Pre-Tension sags / tensions are given in Table 3 of appendices 1 to 6. The erection sags given in Table 4 of appendices 1 to 6 have been calculated from the conductor design tensions.
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The mid span conductor phase spacing generally limits the maximum span lengths detailed in Table 1of appendices 1 to 6. The following values have been used to establish the values in Table 1. The standard conductor spacing is 1.2m on intermediate and terminal supports The conductor spacing for section angle supports ≤ 600 is 1.21m. The conductor spacing for section angle supports ≥ 600 ≤ 750 is 1.11m. The conductor spacing for long span “H” section angle supports ≤ 300 1.93m. The likely maximum conductor temperature for the purpose of assessing clearances is specific to the chosen conductor and is specified in the relevant appendices. The minimum electrical clearance between any energised unsupported conductor and an insulator support, steelwork; stay wire (earthed or unearthed) or stay-bonding device shall not be less than 400 mm. The minimum electrical clearance between energised unsupported conductors shall not be less than 600 mm.
12.13.1 Minimum Height of Line Conductors
The height above ground of any line conductor, or any wire or cable attached to a pole carrying any line conductor, shall not, at its likely maximum temperature be less than the value specified in Energy Networks Document OHL-14-005 at any point. In order to calculate the height above ground of a line conductor, the appropriate sag for the span length and maximum operating temperature must first be selected from Table 2 of the appropriate appendix.
12.13.2 Summary of Statutory Ground Clearances
Road Crossing Ground Not Over Road Connecting Jumpers
5.8m 5.2m 4.3m To ensure compliance with the above Statutory Clearances an additional 450mm shall be allowed on the profile ground clearance at maximum still air sag condition to allow for minor variations in ground level due to farming activities.
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With the line conductors at the likely maximum temperature in still air or deflected at any angle up to 45º from the vertical, the minimum clearances detailed in Energy Networks Document OHL-14-005 shall be achieved.
12.13.4 Clearances to other Power Lines
Where power lines cross over or are in proximity to one another, the voltage of the power line with the higher system voltage as detailed in Energy Networks Document OHL-14-005 shall determine clearances.
12.13.5 Railway and Canal Crossings
When an overhead line is erected along, or across, a railway, canal or navigable river it shall comply with such arrangements as may be prescribed, or as may be agreed with the authorities concerned to meet local or special conditions as detailed in Energy Networks Document OHL-14-005.
12.13.6 Telecommunications Crossings
Where an overhead line to this Specification crosses or is in proximity to a telecommunications line, precautions shall be taken to prevent contact between the two lines as detailed in ER-PO5 .
12.13.7 Road / Motorway Crossings
Where a line to this Specification crosses a motorway or other designated “6.1m high load route” road, the minimum height of the conductors at the likely maximum conductor temperature must be at least 6.9m above the carriageway surface as detailed in Energy Networks Document OHL-14-005. Where it is necessary to employ a “sky cradle” during erection or maintenance works, a clearance of 8.2m must be provided between the line conductor and carriageway surface. Where a “sky cradle” cannot be used, scaffolding should be employed over a motorway. In such instance, a clearance of 14m should be ensured between the line conductor and the surface of a normal 3-lane motorway. Details of the design and use of temporary scaffold guards can be found in ENATS 43-119.
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Safety signs shall be fitted to all supports in accordance with Energy Networks policy EPS-01-004. All poles shall be labelled in accordance with Energy Networks Documents OHL-23-001 or OHL-23-002 as appropriate.
12.15 Anti-climbing Devices
Anti-climbing devices in accordance with ENATS 43-90 shall be fitted to supports in accordance with Energy Networks policy EPS-01-004. Anti-climbing devices shall be fitted to all stays. Out-rigger brackets shall conform to ENATS 43-95 drawing 439516. The minimum quality of barbed wire shall be to BS 4102 Section 4 (galvanised steel) with barbs of 85mm spacing. Similar wire but with the spacing of the barbs set at 50mm is commonly used. In areas where there is the possibility of severe corrosion stainless steel barbed wire is recommended. Wire staples shall comply with BS 1494-1. They shall be of sufficient size to firmly hold the wire in place and be galvanised to BS EN 10244-2.
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Steelwork on poles shall NOT be earthed except where transformers, ground-operated switchgear; cable terminations or surge arresters are to be fitted. At such positions all steelwork and other supporting metalwork mounted on the pole above the anti climbing device shall be bonded and earthed in accordance with the requirements specified hereunder, where the pole is not earthed all steelwork above the anti climbing device shall be bonded together. Steelwork below the anti climbing device shall not be bonded or earthed unless ground operated switchgear operating handles are installed below the anti climber. The Earthing and bonding conductor shall be stranded copper conductors of a minimum cross sectional area of 35mm² for 11kV and 70mm² for 33kV, the Earthing and bonding conductor shall be green/yellow PVC, covered. The top section of stays shall always be bonded to the adjacent steelwork, regardless of whether the steelwork itself is earthed. The Earthing conductor shall be connected to one or more Energy Networks Approved earth rods at a minimum depth of 600mm to establish an earth electrode with a maximum resistance value of 40 ohms. The first earth rod shall be positioned as close as possible to the base of the pole. Where appropriate, deep driving of earth rods can be employed as an alternative to a multi-rod installation. The Earthing conductor shall be protected from the bottom of the pole to above the anti climbing device by an insulated 3.0m long cable guard buried in the ground to a depth of 150 mm. The method of installation of Earthing for switchgear is detailed in Energy Networks Document OHL-25-007.
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Where there is a requirement to install a LV Neutral Earth on any structure the method of installation is detailed in Energy Networks Document OHL-25-002. The Neutral Earth Conductor up to the first earth rod shall be shall be 35mm² copper conductor for transformers up to and including 100kVA and 70mm² copper conductor for 200kVA transformers, The neutral earth conductor up to the first earth rod shall be black in colour and PVC covered.
12.17 11kV Transformers
Transformers in excess of 25kVA and up to and including 100kVA may be mounted on single poles structures on the ENATS 43-95 Transformer Platform arrangement Drawing Reference SP4020581. Transformers in excess of 100kVA shall only be mounted on “H” Poles on the ENATS 43-95 Transformer Platform arrangement Drawing Reference SP4020580. An alternative to an H Pole may be a single pole and lay leg structure. Where a lay leg is the preferred method of installation these poles should be obtained at the required length from the pole supplier, under no circumstances is it acceptable to cut a pole on site to the required length. At such positions all steelwork and other supporting metalwork mounted on the pole above the anti climbing device shall be bonded and earthed in accordance with the requirements specified in 12.16. The down dropper jumpers shall be installed in accordance with the requirements specified in 12.8.2. The methods of installation of Transformers are detailed in Energy Networks Document’s OHL-22-03, OHL-22-04, OHL-22-05, and OHL-22-30. The Transformer LV Neutral Earth shall be installed in accordance with the requirements specified in 12.16.1.
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All switchgear with the exception of those of the un-earthed Hook Stick or Long Stick method of operation shall be installed on Earthed poles in accordance with the requirements specified in 12.16. They shall be erected at the pole top below the line conductors. Surge arresters shall be installed as directed by the Engineer and shall be fitted in accordance with Clause 12.21. For 11kV applications the down dropper jumpers shall be installed in accordance with the requirements specified in Energy Networks Document OHL-22-006. The methods of installation of Pole Mounted Switchgear are detailed in Energy Networks Documents OHL-22-012, OHL-22-013, OHL-22-023, OHL-22-026, OHL-22-027, OHL-22-028 and OHL-22-029.
12.19 Air Break Switch Disconnectors
Air Break Switch Disconnectors shall not be installed on Earthed poles. They shall be of an un-earthed hook stick operated type, erected in a horizontal position at the pole top below the line conductors At such positions all steelwork and other supporting metalwork mounted on the pole above the anti climbing device if fitted shall be bonded in accordance with the requirements specified in 12.16. For 11kV applications the down dropper jumpers shall be installed in accordance with the requirements specified in Energy Networks Document OHL-22-006. The method of installation of ABSD is detailed in Energy Networks Document OHL-22-010.
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Specification for 11kV And 33kV Overhead Lines of Unearthed Construction on Single and
All HV cables shall be terminated on Energy Networks Approved terminations on poles below the conductors in accordance with Energy Networks documents OHL-18-17, OHL-18-18 or OHL-18-19 as appropriate. The jumpers shall be formed in the same conductor as the line conductors and connected to the main line with Energy Networks Approved compression connectors and terminating in an Energy Networks Approved Bi Metallic connector on the cable termination. All connectors shall satisfy the requirements of ENATS 43-92. The HV cable shall be secured from 200mm below ground level up to the termination and it shall be protected from the bottom of the pole to above the anti climbing device by an insulated 3.0m long cable guard buried in the ground to a depth of 150 mm. Cognisance should be taken of the requirements of Energy Networks document OHL-025-007 when considering the routing of the cable and associated earthing system. All metalwork on the pole including the cable termination associated mounting steelwork and metallic cable sheath/screen above the Anti Climbing Device shall be bonded and earthed in accordance with Clause 12.16. Surge arresters shall normally be incorporated in the cable termination and shall be fitted in accordance with Clause 12.21.
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Energy Networks Approved surge arresters shall be fitted to protect cables and elsewhere, where directed by the Engineer. Where surge arrestors are to be erected on a pole, whether incorporated in a cable termination or directly mounted on an item of plant, they shall be connected directly in the current path as close to the plant or cable termination lugs as possible. One continuous 70mm² copper conductor which shall be green/yellow PVC covered, shall be installed directly from the apparatus Earthing terminal or the outer surge arrester to the first earth rod which shall be positioned as close as possible to the base of the pole. The metallic cable sheath/screen of underground cables shall be connected to the crucifix star point, which shall then be connected to the surge arrestor earth by a 70mm² copper conductor, which shall also be green/yellow PVC covered. All other metalwork on the pole including the cable termination associated mounting steelwork above the Anti Climbing Device shall be bonded to the surge arrestor earth by a 35mm² Copper conductor for 11kV and a 70mm² Copper conductor for 33kV applications. The Bonding conductor shall be green/yellow PVC covered in accordance with Clause 12.16. The earth electrode shall have a maximum resistance value of 10 Ohms.
12.22 Insulated Shrouding
Insulated Shrouding shall be fitted to all 11kV plant and equipment as directed by the engineer.
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Specification for 11kV And 33kV Overhead Lines of Unearthed Construction on Single and
“H” Type Wood Poles.
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Table 5-Maximum Angle of Deviation for Single Poles for 50mm2 “HAZEL” AAAC
Grade 1150 Stay Wire Angle of Stay Slope 1 x 7/4.00mm
2 x 7/4.00mm
30° 25° 45° 35° 35° 55° 40° 40° 65° 45° 45° 75°
Table 6-Maximum Angle of Deviation for “H” Poles for 50mm2 “HAZEL” AAAC
Grade 1150 Stay Wire Angle of Stay Slope 2 x 7/ 4.00mm
3 x 7/4.00mm
30° 75° 90° 35° 75° 90° 40° 75° 90° 45° 75° 90°
Note: The minimum grade of pole for angles in excess of 50 shall be Stout as defined in BS1990. For single pole angles between 750 and 1000 a double terminal structure drawing reference SP4000578 shall be used. Where a Double terminal structure is employed it shall be fitted with 4 splayed stays. Where two stays are installed on an H pole structure they shall both be fitted to the outer limb.
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Table 7-Strut Load in Single Poles with One or Two Stays (kgf) for 50mm2 “HAZEL” AAAC Stay Angle
Note:- The minimum pole top diameter for single poles of angles in excess of 130 shall
be 215mm. Note:- The minimum pole top diameter for “H” poles of angles in excess of 310 shall be
225mm.
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Table 12- Pole Sizing for Intermediate and section Poles for 300mm2 “UPAS”AAAC (Severe Weather Area)
Maximum Wind Span Length (m) 50 60 70 80 90 100 115 Pole Length
(m) Diameter of Pole 1.5m from Butt (mm)
8.5 265 265 265 285* 285* 2 x 265 2 x 265 9 275 275 275 295* 295* 2 x 275 2 x 275
9.5 280 280 280* 300* 300* 2 x 280 2 x 280 10 285 285 285* 305* 325* 2 x 285 2 x 285
10.5 290 290 290* 310* 330* 2 x 290 2 x 290 11 295 295 315* 315* 335* 2 x 295 2 x 295
11.5 300 300 320* 320* 340* 2 x 300 2 x 300 12 305 305 325* 325* 345* 2 x 305 2 x 305 13 320 320 340* 340* 360* 2 x 320 2 x 320 14 335 335* 335* 355* 2 x 335 2 x 335 2 x 335 15 350 350 350 370* 370* 2 x 350 2 x 350 16 365 365 365 365* 385* 2 x 365 2 x 365 17 375 375 375 395* 395* 2 x 375 2 x 375 18 390 390 390 390* 410* 2 x 390 2 x 390 20 415 415 415 415* 435* 2 x 415 2 x 415 22 435 435 435 435* 455* 2 x 435 2 x 435
Note:- Pole sizes marked * shall have two blocks fitted
Pole Length (m) Foundation Depth (m)
8.5 -11.0 inc. 2.2 11.5 – 14.0 inc. 2.4 15.0 – 17.0 inc. 2.8 18.0 – 22.0 inc 3.0
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Appendix 7 Installation requirements for Conductors incorporating Optical Fibres
13 INTRODUCTION
This Appendix has been prepared to provide a design for 33kV overhead lines suitable for installation on the companies’ network, utilising optical fibre communication cores embedded within the phase conductors. The optical fibres are enclosed within two separate stainless steel tubes in a phase conductor. This appendix is complementary to the equivalent standard conductor installation requirements, and should be read in conjunction with it. This appendix details the specific stringing requirements for: - 200mm² AAAC POPLAR Equivalent OPPC (L34) 300mm² AAAC UPAS Equivalent OPPC (L36).
13.1 General
When compared to a standard overhead line construction, lines incorporating optical fibres shall have the centre phase conductors substituted with an equivalent optical phase conductor (OPPC). All overhead line components and design parameters shall comply with the requirements of the standard conductor as specified in the relevant appendix with the exception of those specified in the following clauses.
There are specific installation techniques, which require to be employed when installing lines incorporating optical fibres within the conductors; these are documented in Energy Networks document OHL-18-022.
13.1.1 Optical Phase Conductors
The maximum working tension of an equivalent OPPC is designed to be the same as for a standard AAAC conductor. However, due to the difference in physical construction of the OPPC when compared with standard conductor, the maximum sag of the OPPC will be marginally less than standard conductor, therefore the maximum design sag for the standard conductor should be used when profiling as indicated in Table 2 of the relevant appendix.
13.1.2 Crossarms, Supports and Stays
As the loadings for the equivalent OPPC are almost identical to the standard conductor, structure sizing, stay strength and their deployment, and Crossarm sizing shall all be as detailed in the relevant standard conductor appendix.
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13.2 Materials
Except where otherwise specified, all materials used in the construction of lines to this Appendix shall comply with current British Standards, ENA Technical Specifications and international standards where appropriate. Only Energy Networks Approved materials shall be used.
13.2.1 Optical Phase Conductors (OPPC)
The optical conductors physical and electrical parameters considered by this specification are detailed in Energy Networks document OHL-03-96, each conductor shall incorporate two stainless steel buffer tubes each containing a minimum of 12 single mode optical fibres.
13.2.2 Vibration Damper
As for standard 33kV line construction, no vibration dampers are normally required to be employed on the OPPC.
13.2.3 Suspension Components
33kV polymeric post insulators and armour grip suspension clamps shall be used at all intermediate insulator positions; the proposed suspension arrangements are not designed to take any uplift load. Where the structure is deemed to be in uplift, the line should be sectioned and tension support components employed in accordance with Section 11.1.
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From termination strap on the Crossarm, the following components are required for the OPPC:
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13.3 Optical Splice Enclosures
At OPPC in-line splice and terminal positions, only Energy Networks Approved fibre optic splice enclosures may be installed. These fitting comprise of a rigid stand off composite insulator and one or two fibre optic splice chambers where appropriate. At Terminal positions these will be mounted on two H Pole Carry Over Channels as detailed in Energy Networks Drawing Reference SP4008885 and secured using two transformer-clamping plates as detailed in ENATS drawing reference 439529. At in-line splice positions, on “H” Pole section structures the unit will be mounted on the centre phase conductor section strap, on Single pole section structures the unit will be mounted on the outside of the angle on the section crossarm this component shall be substituted for items 11 & 13 of the general assembly drawings They will be located on section and terminal structures as indicated on Energy Networks drawing reference SP4019865. In order to prevent damage to the stainless steel buffer tubes containing the Optical Fibres the line conductor should be dressed directly from the dead end fitting directly to the splice enclosures and should be installed in such a manner to ensure the minimum-bending radius of the conductor is not compromised. Only Energy Networks Approved persons shall carryout the splicing of the optical fibres.
13.3.1 Electrical Connections
At terminal positions where a load carrying electrical connection is required for example to a cable termination these should be connected to the Splice enclosure jumper by one or two 3-bolt parallel groove clamps. (See also general arrangement drawings and associated component listings). Parallel Groove clamps should be used for all electrical connection associated with the OPPC. It is essential that all conductors are thoroughly cleaned using a suitable wire brush and a Energy Networks approved conductive paste should be applied to the conductor prior to the application of the parallel groove clamps; the clamps should be tightened with a suitable torque wrench to the manufacturers recommended torque. Compression fittings must not be applied to the OPPC conductor. At Splice Enclosures, the termination connecting rod should be cleaned using 150-grade abrasive paper and an Energy Networks approved conductive paste should be applied to the conductor and connecting rod prior to the application of the parallel groove clamp(s).
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13.4 Earthing
As is normal practise all metalwork including Optical Splice Enclosures on all structures shall be bonded and or earthed in accordance with Energy Networks document OHL-25-01. A connection hole is provided on the base plate of the Optical Termination Unit to which the earth-bonding lug should be connected.
13.5 Optical Fibre Cable Connections
The Fibre Optic underground cables shall secured every 500mm down the pole and protected at the bottom of the pole by cable guards 3.0m long sunk 150mm into the ground .
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General Arrangement OPPC Splice Enclosures
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Poplar Equivalent Optical Conductor (Non Severe Weather Area) (L34)
Specification for 11kV And 33kV Overhead Lines of Unearthed Construction on Single and
“H” Type Wood Poles.
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Appendix 8 Installation Requirements for Horse OPGW This Appendix has been prepared to provide a design for a OPGW conductor to replace the existing “Hardex” communication network on existing 33kV overhead lines structures This appendix details the specific stringing requirements for a 70mm² ACSR Horse Equivalent OPGW
14 General
Where there is a requirement to modernise the existing “Hardex” communication network an Optical Ground wire may be employed in accordance with the following requirements. There are specific installation techniques, which require to be employed when installing conductors incorporating optical fibres; these are documented in Energy Networks document OHL-18-022.
14.1.1 Optical Ground Wire
The maximum working tension of an equivalent OPGW is designed to be the same as for a standard AACSR conductor. However, due to the difference in physical construction of the OPGW when compared with standard conductor, the maximum sag of the OPGW will be marginally less than standard conductor, therefore the maximum design sag for the OPGW conductor may be used when profiling as indicated in Table 2 of this Appendix. See Section 12.13.1 for guidance on minimum height of conductors. Note:- Land usage may have changed since the original line was profiled and obstacles may have been erected which could infringe on the basic requirements set out in section 11.13.1 therefore it is recommended this is given full consideration.
14.1.2 Supports and Stays
As the loadings for the OPGW are not significantly greater than the “Hardex” Communication cable there are no requirements to alter existing structures.
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14.2 Materials
Except where otherwise specified, all materials used in the construction of lines to this Appendix shall comply with current British Standards, ENA Technical Specifications and international standards where appropriate. Only Energy Networks Approved materials shall be used.
14.2.1 Optical Ground Wire (OPGW)
The optical Ground Wire considered by this Appendix is detailed in Energy Networks document OHL-03-96; each conductor shall incorporate two stainless steel buffer tubes each containing a minimum of 12 single mode optical fibres.
14.2.2 Vibration Damper
No vibration dampers are normally required to be employed on the OPGW .
14.2.3 Suspension Components
The OPGW shall be supported at all intermediate positions using a standard pole outrigger bracket (ENATS Drawing Reference 431403) in conjunction with a galvanised steel suspension link connected to an Armour Grip Suspension Clamp. The pole bolt securing the outrigger bracket should be positioned 225mm above the profiled OPGW position to allow for the suspension components. The proposed suspension arrangements are not designed to take any uplift load. Where the structure is deemed to be in uplift, the line should be sectioned and tension support components employed in accordance with Section 12.1.
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14.2.4 Horse Equivalent Tension String Components
From the BS3288 Ref 14/88 eyebolt on the structure the following components are required for termination of the OPGW:
Item Part name Q'ty Load Rating 1 Protection rods 1 70 kN 2 Dead end 1 70 kN 3 Thimble 1 100 kN 4 400 mm Link 1 70 kN
4
2
1
Cable
3
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Specification for 11kV And 33kV Overhead Lines of Unearthed Construction on Single and
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14.2.5 Connection to Splice Enclosures
At OPGW intermediate and terminal splice positions an optical fibre splice enclosure is required to facilitate the splicing of the optical fibres. The optical splice enclosure shall be fixed above anti climber level and secured using two 10mm x 75mm galvanised coach bolts. At terminal positions the Fibre Optic underground cables shall be secured every 500mm down the pole and protected at the bottom of the pole by cable guards 3.0m long sunk 150mm into the ground.
14.3 Conductor Design/Erection Sags and Tensions
Conductor design Sags and tension are given in Tables 2 & 3 of this appendix. The original lines incorporating “Hardex” Communications cables were profiled using a “Wolf” Sag template (normally 500C) The design sag of the Horse OPGW replacement at an Assumed maximum ambient temperature of 450C whilst greater than the “Hardex” is equal to or slightly less than the Wolf Profile used when the line was originally planned and hence the Horse OPGW may be strung as a direct replacement for the “Hardex” communications’ cable. The erection tensions given in Tables 3 of this appendix are based on the conductor design tension, but have been subjected to an over tension equivalent to a -130C temperature shift to allow for bedding in of the strands and long term creep of the conductor during the life of the line. No pre-tensioning or other adjustments is necessary during the erection of the line
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Specification for 11kV And 33kV Overhead Lines of Unearthed Construction on Single and
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14.4 Location of OPGW Attachment Points on Structures.
The Attachment positions for OPGW on all structures will be as follows:-
14.4.1 Straight Section, Intermediate and Pin Angle Structures
The Outrigger Bracket (ENATS Drawing Reference 431403) shall be installed 1365mm below phase conductors for spans up to 107m. 1675mm below phase conductors for spans up to 152m.
14.4.2 Angle Section and Terminal Structures
The Eye Bolt (ENATS Drawing Reference 439603) shall be installed 1520mm below phase conductors for spans up to 107m. 1830mm below phase conductors for spans up to 152m
14.5 Bonding and Earthing of OPGW and Components
As is common with all metalwork on structures constructed to this specification At Optical Splice enclosure positions the splice enclosure will be required to be bonded in accordance with section 12.16. The OPGW shall also be bonded to all steelwork on the structure in addition it shall be earthed at intervals of approximately 400m in accordance with section 11.16.
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Specification for 11kV And 33kV Overhead Lines of Unearthed Construction on Single and
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Figure 1 11Kv Single Pole Member Drilling, Scarfing and Marking............................................................................. 144
Figure 2 11Kv H Pole Member Drilling, Scarfing and Marking..................................................................................... 145
Figure 3 33Kv Light Construction Single Pole Member Drilling, Scarfing and Marking........................................ 146
Figure 4 33Kv Light Construction H Pole Member Drilling, Scarfing and Marking................................................ 147
Figure 5 33Kv Heavy Construction Single Pole Member Drilling, Scarfing and Marking ...................................... 148
Figure 6 33Kv Heavy Construction H Pole Member Drilling, Scarfing and Marking .............................................. 149
Figure 7 Delta H Pole Drilling Scarfing and Marking....................................................................................................... 150
Figure 8 Single Pole Intermediate or Pin Angle (Drawing SP2147473) ........................................................................ 151
Figure 9 Single Pole Intermediate or Pin Angle (Drawing SP4018552) ........................................................................ 153
Figure 10 “H” Pole Intermediate Long Span (Drawing SP4019155) ............................................................................. 155
Figure 11 Single Pole Straight Line or Angle Section (Drawing SP2147476) .............................................................. 157
Figure 12 Single Pole Straight Line or Angle Section (Drawing SP4018548)........................................................................... 159
Figure 13 “H” Pole Straight Line or Angle Section (Drawing SP4019003) .............................................................................. 161
Figure 14 Long Span “H” Pole Straight Line or Angle Section (Drawing SP2147486)........................................................... 163
Figure 15 Delta “H” Pole Section or Section Angle (Drawing SP2059611) .............................................................................. 165
Figure 16 Delta Long Span “H” Pole Section or Section Angle (Drawing SP2059372) ........................................................... 167
Figure 17 Single Pole Terminal (Drawing SP2147474)............................................................................................................... 169
Figure 18 “H” Pole Terminal (Drawing 2147485)....................................................................................................................... 171
Figure 19 Single Pole Double Terminal (Drawing SP4000578) ................................................................................................. 173
Figure 20 General Arrangement Intermediate Crossarm (Drawing SP4018402).................................................................... 175
Figure 21 General Arrangement Section Crossarm (Drawing SP4018433) ............................................................................. 176
Figure 22 General Arrangement Terminal Crossarm (Drawing SP4018401).......................................................................... 177
Figure 23 General Arrangement Long Span Crossarm (Drawing SP4017663) ....................................................................... 178
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Specification for 11kV And 33kV Overhead Lines of Unearthed Construction on Single and
Figure 52 General Assembly Transformer Platform Steelwork for an “H” Pole (Drawing SP4020580) .............................. 207
Figure 53 General Arrangement Single Pole Bog Shoe (Drawing SP2146665) ........................................................................ 208
Figure 54 General Arrangement “H” Pole Bog Shoe (Drawing SP........................................................................................... 209
Figure 55 General Arrangement Bog Shoe Strut (Drawing SP2146662) .................................................................................. 210
Figure 56 General Arrangement 300 Angle Bracket................................................................................................................... 211
Figure 57 General Arrangement Wind Stay Attachment .......................................................................................................... 212
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Specification for 11kV And 33kV Overhead Lines of Unearthed Construction on Single and
General Assembly Delta Long Span “H” Pole Section or Section Angle (Drawing SP2059372) ITEM NUMBER DESCRIPTION ENATS, BS or OTHER
REFERENCE DRAWING NUMBER
COMMODITY CODE NO.
01 2 Wood Pole ENATS 434001 - - 02 2 or 4 Pole Block ENATS 439103 Type 2 SP4019020 C43810342 05 2 Terminal Crossarm Member ENATS 439522 SP4018401 C43811080 06 2 Long Span Crossarm Member ENATS 439521 SP4017663 C43811079 09 2 Terminal Strap ENATS 439528 SP4017664 C43811074 11 2 Pin Insulator ENATS 43-93 - - 13 2 Pilot Pin 50mm Shank BS3288 Fig 5, Ref 50 - C43270177 14 2 Helical Ties ENATS 43-15 - - 15 6 Ball End Hook BS3288 Fig 12 Ref 15/32 - C43238026 16 6 Tension Insulator ENATS 43-93 - C43200548 17 6 Helical Dead End Assembly ENATS 43-92 - - 18 3 Non Tension Joint - - -
19 8 or 10 M20 Pole Bolt (HYS) and Nut. Length to suit Pole diameter
ENATS 43- 96 Clause 4.2 (Grade 8.8 HYS) - -
20 9 M20 Tie Rods ENATS 439608 Type 2 or 3 - C43811060 21 8 M20 x 60mm Assembly Bolt and Nut ENATS 43- 96 Clause 4.2 - C43602072 22 6 or 8 M20 Square Curved Washer ENATS 439605 - C43602025 23 4 or 6 M20 Square Flat Washer ENATS 439604 - C43602050
24 2 or 4 Safety Sign English Bilingual - - C06294004
C06293900 25 As Required Pole Numbers - - - 28 2 Foundation Brace Steelwork 1830mm centres ENATS 439558 SP4017651 C43500935 29 1 Foundation Brace Block ENATS 439112 Type 1 SP4019036 C43811796 32 2 Long Section Strap For Long Span Delta H Pole - SP4019183 - 41 4 Long Span Delta Crossarm Strut - SP2143987 -
As Required Hardwood Plugs ENATS 439516 - -
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Specification for 11kVAnd 33kV Overhead Lines of Unearthed Construction on Single and