Assumption University Thailand EE4503 Electrical Systems Design Raceways 1.

Assumption University Thailand

EE4503Electrical Systems Design

Raceways

1


Topics

• Introduction to Raceways

• Conduits

• Conduit Installations

• Wireways, Auxiliary Gutters, Cable Trays

• Fittings

2


Raceways

• Damage e.g. physical, chemical

• Human Contact

• Easy Wiring e.g. wiring, maintenance

• Grounding for Metal Conduit

• Limit the scope of damage e.g. fire, short circuit

3


Conduits – RMC, IMC, EMT

Catalog of Panasoics

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Conduits – RMCRigid Metal Conduit

• Strongest conduit (except concrete :p)

• (Usually) Galvanized

• Usage: All weather, all terrain

• Standard: ” – 6” (15mm – 150mm) and 3m length

5


Conduits – IMCIntermediate Metal Conduit

• Thinner than RMC

• (Usually) Galvanized

• Usage: All weather, all terrain

• Standard: ” – 4” (15mm – 100mm) and 3m in length

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Conduits – EMTElectrical Metallic Tubing

• Thinner than IMC & RMC

• Not allow to have thread

• Usage: Only in building (not under ground, not for high voltage)

• Standard: ” – 4” (15mm – 100mm) and 3m in length

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Conduits – FMC

http://www.delikon.com/brass.htm

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Conduits – FMCFlexible Metal Conduit

• Metal conduit with the high flexibility

• Usage: Vibration or Need Bending

• Standard: ” – 3” (15mm – 80mm)

• Installation: Need support every 1.5m and 0.3m

(in case of termination point / junction box)

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Conduits – RNCRigid Nonmetallic Conduit

• Built from nonmetallic material: e.g. PVC

• Disadvantage: Not as strong as metal and limit

temperature usage

• Advantage: Sustain to erosion, humidity, impact

• Usage: Exposed, Conceal, Wet & Himid or underground (usually using “duct bank”)

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Conduits – RNCDuct Bank

http://www.chana.egat.co.th/newweb/gallery/?level=picture&id=28http://www.iowaconcrete.com/node/707

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Conduits – Comparison

http://www.mc2-ice.com/services/estref/popular_conversion_files/electrical/conduit_weight.html

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Conduits Installation: RMC, IMC

http://www.mikeholt.com/instructor2/img/product/pdf/1259687476sample.pdf

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Wet Location: accessories needed to be specified as

“Raintight” or “Wet locations”



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Cinder Fill: In corrosive area (e.g. under

permanently moist), required at least 2” concrete



http://www.electrix.co.uk/view_product_options.php?id=1117http://ecmweb.com/site-files/ecmweb.com/files/archive/ecmweb.com/images/112ecmCBfig1.jpg

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Box: Where conduit reaching the box, “bushing” is

required to protect the cable’s



Electrical Systems Design: ประสิ�ทธิ์�� พิ�ทยพิ�ฒน์�http://www.tpub.com/ceb/71.htm

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Bend: Number of bends in one run should <= 360o


Conduits Installation - Supports

Electrical Systems Design: ประสิ�ทธิ์�� พิ�ทยพิ�ฒน์�http://www.ci.oceanside.ca.us/civica/filebank/blobdload.asp?BlobID=22230

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Splices and Taps: only inside the box

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http://www.diyadvice.com/diy/electrical/fans-heat/whole-house-ventilating-fan/http://www.familyhandyman.com/DIY-Projects/Lighting/Kitchen-Lighting/how-to-install-under-cabinet-lighting-in-your-kitchen/View-All


Conduits Installation - # of Cables

• Need space inside conduit:

– Heat Ventilation

– Cable’s insulator will not be damaged.

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http://www.simpullsolutions.com/documents/SIMpullTHHNInstallationandApplicationGuide8-15-07.pdf


Conduits Installation - # of Cablestable

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http://www.telepart.net/ตารางการต�ดต��งสิายไฟใน์ท�อWire-Conduit-Table.html


Conduits Installation - # of Cablescalculation

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Calculate directly from the cable’s outer diameter () and conduit’s inner diameter () and is the number of cables.


Wireways

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http://www.indochinaengineering.co.th/product.php?id_product=30


Wireways• Raceways are folded from sheet metal.

• General usage in open area. If outside building, specify “Raintight”

• Not use when risk of severe physical damage.

• Height: 50, 75, 100, 150, 200 mm

• Width: 50, 75, 100, 150, 200, 250, 300 mm23


Wireways

• Use current rated for the metal conduit.

• Use reduction factor, if > 30 cables.

• Need supports for every 1.5m.

• Cannot use through the wall or floor.

• Cannot use as grounding cable.

• Use no more than 20% fill.24


Auxiliary Gutters

• Similar to wireways

• Collect the cable before distribute.

25

http://www.contractortalk.com/f32/some-recent-work-34277/


Cable Trays

26

http://www.indochinaengineering.co.th/product.php?id_product=32


Cable Trays• Cable Tray is not Raceways, but is

commonly used in industry to support cable.

• Cheap and easy to use.

• Only for specific cable types, e.g. multi-core cables

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Cable Trays – Ladder TypeFor heavy-duty power distribution

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http://www.shreemahalaxmisteel.com/cable-trays.htmlhttp://www.ezziengineering.com/images/Cable_Tray_Catalogue.pdf


Cable Trays – Perforated TypeFor power cables, small cables and control cables

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http://www.shreemahalaxmisteel.com/cable-trays.htmlhttp://www.ezziengineering.com/images/Cable_Tray_Catalogue.pdf


Cable Trays – Solid Bottom TypeFor small cables.

30

http://www.ezziengineering.com/images/Cable_Tray_Catalogue.pdf


Cable Trays – Comparison

http://www.cooperindustries.com/content/dam/public/bline/Resources/Library/catalogs/cable_tray_systems/all_products/CTManual.pdf 31


Fittings

• Accessories to be used with race way.

• Purpose

– To firmly hang the raceway

– To smoothly change the direction of raceway

– To easily pull the cable into the raceway

– To properly splice the cables

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Fittings - Boxes

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• Termination point (switch, receptacle) or Stop point (splice, tap) for the wiring system.

• Metal or non-metal.

• Sizing is based on the required space.

• Have no hole for the object larger than 7.5 mm in diameter to pass thru.


Fittings - Boxes

http://www.topaz-usa.com/catalogs/electrical_fittings_catalog.pdf

34


Fittings – Pull Boxes

http://ecmweb.com/code-basics/sizing-junction-boxes

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Fittings – Pull Boxesstraight pulls


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The horizontal dimension (A) is 8 times of the largest raceway size.


Fittings – Pull Boxesangle pulls


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The distance between raceways (C) is 6 times of the diameters of the raceways.


Fittings – Other AccessoriesConnectors

http://www.topaz-usa.com/catalogs/electrical_fittings_catalog.pdfhttp://numthaveerung.co.th/pdf/Steel%20Conduit-Accessories%20Fitting.pdf

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• Steel Coupling

• Compression

• Set Screw

• Rain Tight


Fittings – Other AccessoriesBushing


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• Metal

• Non-metal

• Grouding


Fittings – Other AccessoriesElbow & Strap


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• Elbow

• Strap


• Electrical Systems Design: ประสิ�ทธิ์�� พิ�ทยพิ�ฒน์�

Reference

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Assumption University Thailand EE4503 Electrical Systems Design Raceways 1.

Documents

pptconduits installation

pptconduits fmchttp

pptconduits comparisonhttp

pptconduits rncduct

metal conduitlimit

imcelectrical systems

wet himid

grounding cable