EXAMPLE: A 20,000 SQ. FT. OFFICE BUILDING IS SERVE BY A 480Y/277V, THREE SERVICE. THE BUILDING CONTAIN THE FOLLOWING LOADS: - 10,000 VA, 208V, THREE PHASE SIGN - 100 DUPLEX RECEPTACLE SUPPLYING CONTINUOUS LOADS RATED AT 180 - 30 FT LONG SHOW WINDOW - 12KVA, 208Y/120V, THREE PHASE ELECTRIC RANGE - 10KVA, 208Y/120V, THREE PHASE ELECTRIC OVEN - 20KVA, 480V, THREE PHASE WATER HEATER - SEVENTY FIVE 150W, 120V INCANDESCENT OUTDOOR LIGHTING FIXTURE - TWO HUNDRED 200 VA INPUT, 277 V FLUORESCENT LIGHTING FIXTURES - 7.5HP, 480V, THREE PHASE MOTOR FAN COIL UNIT - 40KVA, 480V, THREE PHASE ELECTRIC HEATING UNIT - 60A, 480V, THREE PHASE AIR CONDITIONING UNIT STEP 1: Calculate the load for the 100 receptacles 100 x 180VA = 18,000VA First 10,000VA @ 100% 10,000VA Remainder @ 50% 4,000VA 14,000VA 125% x 14000VA =17,500VA (CONTINUOUS LOAD) STEP 2: Calculate the load for the show window using 200VA per 200 x 30ft = 6,000VA 125% x 6000VA = 7,500VA (CONTINUOUS LOAD) Apply demand factor from NEC Table 220.44
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
EXAMPLE:
A 20,000 SQ. FT. OFFICE BUILDING IS SERVE BY A 480Y/277V, THREE PHASE
SERVICE. THE BUILDING CONTAIN THE FOLLOWING LOADS:
- 10,000 VA, 208V, THREE PHASE SIGN
- 100 DUPLEX RECEPTACLE SUPPLYING CONTINUOUS LOADS RATED AT 180VA EACH
- 30 FT LONG SHOW WINDOW
- 12KVA, 208Y/120V, THREE PHASE ELECTRIC RANGE
- 10KVA, 208Y/120V, THREE PHASE ELECTRIC OVEN
- 20KVA, 480V, THREE PHASE WATER HEATER
- SEVENTY FIVE 150W, 120V INCANDESCENT OUTDOOR LIGHTING FIXTURES
- TWO HUNDRED 200 VA INPUT, 277 V FLUORESCENT LIGHTING FIXTURES
- 7.5HP, 480V, THREE PHASE MOTOR FAN COIL UNIT
- 40KVA, 480V, THREE PHASE ELECTRIC HEATING UNIT
- 60A, 480V, THREE PHASE AIR CONDITIONING UNIT
STEP 1: Calculate the load for the 100 receptacles
100 x 180VA = 18,000VA
First 10,000VA @ 100% 10,000VA
Remainder @ 50% 4,000VA
14,000VA
125% x 14000VA =17,500VA (CONTINUOUS LOAD)
STEP 2: Calculate the load for the show window using 200VA per linear foot
200 x 30ft = 6,000VA
125% x 6000VA = 7,500VA (CONTINUOUS LOAD)
STEP 3: Calculate the incandescent outside lighting
Apply demand factor from NEC Table 220.44
75 x 150VA = 11,250VA
125% x 11250VA = 14,060VA (CONTINUOUS LOAD)
STEP 4: Calculate the load for 10KVA Sign Lighting
10KVA x 1000 = 10,000VA
125% x 10000VA = 12,500VA (CONTINUOUS LOAD)
STEP 5:
12KVA x 1000 = 12,000VA
STEP 6:
10KVA x 1000 = 10,000VA
STEP 7: Determine the sum of yhe load on the 208/120V lighting panel
Non-continuous load:
Range 12000
Oven 10000
TOTAL 22000
Continuous load:
Recaptacles 14000
Show Window 6000
Outside lighting 11250
Sign Lighting 10000
TOTAL 41250
Total Feeder Load
Non-cont.l 22000
Cont.l @ 125% 51563
TOTAL 73563
STEP 8: Determine the feeder rating for the subpanel
73,563 / (1.732 x 208) = 204Amp
Calculate the load for 12KVA range NEC sec 220.56
Calculate the load for 10KVA oven NEC sec 220.56
STEP 9:
Wire size: 4/0 THHN
CB size 225 A
STEP 10: Determine the 3-phase transformer over current protective devices
both primary and secondary sides.
Total Load: 73563
Vpri 480
Vsec 208
Ipri =73563/(1.732*480)
= 88.5 Amp
Isec =73563/(1.732*208)
= 204 Amp
Over current protective device
Pri =88.5 x 250%
= 221 Amp
Sec =204 x 125%
= 255 Amp
Use: 300 Amp CB
Refer to NEC Table 310.16
Refer to NEC Table 450.3(B)
- 100 DUPLEX RECEPTACLE SUPPLYING CONTINUOUS LOADS RATED AT 180VA EACH
(CONTINUOUS LOAD)
Calculate the load for the show window using 200VA per linear foot
(CONTINUOUS LOAD)
(CONTINUOUS LOAD)
(CONTINUOUS LOAD)
Determine the 3-phase transformer over current protective devices
LOAD SCHEDULE
VOLTAGE:208 Y / 120V, 3-PHASE, 4-WIRE, 60HZ
CKT. BREAKER
NO. PHASE AT AF
1 1 150 250
2 1 70 100
3 1 125 250
4 3 35 100
5 3 35 100
6 3 30 100
PANEL BOAD TAG.
208 Y / 120V, 3-PHASE, 4-WIRE, 60HZ LOCATION .
SIZE OF WIRE LOADS DESCRIPTION
50 mm2 RECEPTACLE LOAD
14 mm2 SHOW WINDOW, 30FT LONG
38 mm2 INCANDESCENT OUTSIDE LIGHTING
8 mm2 SIGN LIGHTING, 208V, 3-PH
8 mm2 ELECTRIC RANGE, 208V, 3-PH
8 mm2 ELECTRIC OVEN, 208V, 3-PH
CONNECTED LOAD / PHASE (W)
TOTAL CONNECTED LOAD IN WATTS
LOAD CURRENT IN AMPS
MAIN CIRCUIT BREAKER - TRIP/FRAM
FEEDER CABLE SIZE
SUPPLIED FROM
208 LIGHTING PANEL MOUNTING
FEEDER ENTRY
CONNECTED LOAD CONNECTED LOAD / PHASE
PER CKT WATTS A B C ABC
17500 17500
7500 7500
14063 14063
12500 12500
12000 12000
10000 10000
17500 7500 14063 34500
73563
204
225 / 250
3 x 50 mm2 + 1 x 25 mm2, CU / XLPE / SWA / PVC (LAID IN CONDUIT)
The "STANDARD" Submersible Motor is a three phase squirrel cage induction, Wet Type Motor, designed to operate with high efficiency. Standard Submersible pump is a multistage centrifugal pump coupled with motor, the Maintenance-free pumpset is suspended vertically from the rising main, it is installed in Tube wells, open wells, Lakes, Rivers etc...
Applications:
Drinking water for high rise buildings.
Industrial Plants and Cooling Towers.
Fountains, Fire fighting, Mining etc.,
Special Features:Low Capital CostMotor can operate satisfactorily with Input Voltage Ranging from 350V-415V (3Phase) 50 HzVibration free & NoiselessHigh Overall Efficiency
No Lubrication is necessary
Optimum Power Consumption
Main Features:Can be easily and quickly installedNo foundation or Pump house requiredSubmersion of Pumpsets ensures quiet and silent operation
Accurately matched pump and motor
After Sales facilities and replacement components readily available
Suitable for 150mm Bore size
Outside dia of Pump set ranges from 139 to 142mm.
Pump Specifications:
A distinction is made between pumps with radial or mixed flow impellers depending on the head and discharge. All the assembled Pumpsets have Head/discharge characteristics matching with the guaranteed duty point.
Motor Specifications:"STANDARD" Submersible Motors are Three phase Wet Type Squirrel Cage Induction motors, designed to operated completely submerged.
Material Construction Details:
Rotor Shaft: Stainless Steel
Rotor: Epoxy coated and dynamically balanced
Stator: Stator winding consists of copper conductor insulated with a tough heat Resistant PVC, which is impervious to water and has a high insulation resistance.
Motor Casing: Steel tubes with epoxy coating.
Stampings: Best Quality Electrical grade Stamping for high efficiency.
Thrust Bearing: Made out of leaded bronze special grade with ferodol combination water lubricated lapped with smooth surface to avoid wear and tear.
Casting: High grade Grey Cast Iron FG 200
Impellers: Gunmetal/Stain less Steel/Poly carbonate dynamically balanced.
Special Features(V4):
Fully rewindable and water lubricated motor.
Available for three phase and single phase.
Motor ratings from 0.50 HP to 5 HP (0.33 KW to 3.7 KW)
Pump water up to 135 mtrs head
Light weight and easy to install
Priming not necessary
Motor is made of high quality stampings, enclosed in stainless steel motor body
Pump is made of high quality stainless steel jacket, noryl impeller set.
Advantages :
Cost Savings:
Installation and maintenance cost is lowEliminates intermediate storage sumps & pumps rooms
Safety:
Higher efficient design hence lower power cost, loess wear and tear.
Negligible noiseNo contamination in drinking water, water lubricated motor.
Applications:Domestic and commercial water supply to apartments,
bungalows, complexes and factories.Garden, farms, nurseries and restaurants/hotels.Irrigation-open, drip and sprinkler.
Fire fighting services.
mining and Construction sites.
SQUIRREL-CAGE AND WOUND-ROTOR AMPERES UNITY POWER FACTOR* AMPERES2300V 230V 460V 575V 2300V
Submersible Motor is a three phase squirrel cage induction, Wet Type Motor, designed to operate with high efficiency. Standard Submersible pump is a multistage centrifugal pump coupled with motor, the Maintenance-free pumpset is suspended vertically from the rising main, it is installed in Tube
full load depending on amount of compounding
Where high starting torque and fairly constant
CONDUIT SIZE IN mm0.5 0.75 1 1.25 1.5 2
12.75 19.13 25.50 31.88 38.25 51.00
AWG MM26 144 222 301 38
1/0 502/0 603/0 804/0 100
INCHES 0.5 0.75 1 1.25MM 12.7 19.05 25.4 31.75
2.5 3 3.563.75 76.50 89.25
1.5 2 2.5 338.1 50.8 63.5 76.2
FROM: ELECTRICIAN POCKET MANUAL (PAGE 21)
ast updated Nov 24, 2008 @ 10:44pm
NEMA Configurations
Terminology
Here is the distinction between plugs, receptacles, inlets and connectors.
Cord Mounted
(female)
Connected to load
(male)
Terminology
NEMA Configurations
NEMA Nomenclature
Confused about the multitudes of plug, connector and receptacle combinations? This page will help. The National Electrical Manufacturers Association (NEMA) has assigned designations to the various configurations. The purpose of so many different types is to prevent the wrong combinations of electrical systems from being plugged together, thereby avoiding potentially dangerous conditions.
Flange or Box Mounted
Connected to live source of electricity
receptacle - A female flange mounted wiring device with the conducting elements recessed behind the mating surface. Often referred to as an outlet. This type of device is normally wired to be live when nothing is plugged in to it.
connector - A female cord mounted wiring device with the conducting elements recessed behind the mating surface. This type of device is normally wired to be live when nothing is plugged in to it. Therefore, connectors are
inlet - A male flange mounted wiring device with the conducting pins protruding and exposed. This type device should never be wired to make the exposed pins live while the mating device is unplugged.
plug - A male cord mounted wiring device with the conducting pins protruding and exposed. This type device should never be wired to make the exposed pins live while unplugged. Therefore, plugs are always dead until they are plugged into a power source
NEMA Configurations
This chart shows the most common NEMA configurations in use in North America for 125ac and 250Vac single phase systems. This covers most residential applications.
Twist-lock devices have the advantage of locking in the mating position. This is useful in applications where the connection experiences vibration or the associated cord is hanging or subject to accidental unplugging.
Additional configurations are defined in the ANSI/NEMA WD 6 standard which cover higher voltages, 3 phase applications, and specific purposes such as travel trailers, marine ship-to-shore and more.
NEMA Nomenclature
Are YOU ready for the next power outage?
The NEMA nomenclature for the code numbers follows this table.
If you have a NEMA code number for a device, use this table to determine the device ratings.
1 Video Introduction 6 NoOutage Configurations11 Placing Order16 Future Technologies21 Our Customers26 What's New
2 Outage Archives 7 Safety 12 Equipment Leasing17 Electricity Glossary22 Pick a Contractor27 Contacting Us
3 Utility Industry 8 Sizing for Your Needs13 Books & Videos 18 Help with Plug Types23 Privacy Promise28 Generator Shortage
4 Why You Need Backup 9 Voltage Drop Calculator14 Financing19 Who We Are24 Safe Shopping Guarantee29 Parts & Service
5 Personal Stories 10 Test Reports15 Frequently Asked 20 Why Buy Here25 Terms & Conditions30 Made in USA
31 Links
We welcome your feedback or questions. Click here to contact us.See our Terms & Conditions before using information or ordering from this web site.
Confused about the multitudes of plug, connector and receptacle combinations? This page will help. The National Electrical Manufacturers Association (NEMA) has assigned designations to the various configurations. The purpose of so many different types is to prevent the wrong combinations of electrical systems from being plugged together, thereby avoiding potentially dangerous conditions.
Confused about the multitudes of plug, connector and receptacle combinations? This page will help. The National Electrical Manufacturers Association (NEMA) has assigned designations to the various configurations. The purpose of so many different types is to prevent the wrong combinations of electrical systems from being plugged together, thereby avoiding potentially dangerous conditions.
Confused about the multitudes of plug, connector and receptacle combinations? This page will help. The National Electrical Manufacturers Association (NEMA) has assigned designations to the various configurations. The purpose of so many different types is to prevent the wrong combinations of electrical systems from being plugged together, thereby avoiding potentially dangerous conditions.
Confused about the multitudes of plug, connector and receptacle combinations? This page will help. The National Electrical Manufacturers Association (NEMA) has assigned designations to the various configurations. The purpose of so many different types is to prevent the wrong combinations of electrical systems from being plugged together, thereby avoiding potentially dangerous conditions.
Transformer Amperes LOAD = 250 W HPS ( FOR LIGTHING POLE)QTY = 50 PCS
1. TWO-WIRE SINGLE PHASE CIRCUIT CABLE = XLPE /PVC (INDUCTION NEGLIGIBLE): POLE HT = 6 METERS
V = (2k X L X I) / d^2 = 2R X L X I R OF CAB = OHM / MV SOURCE = 220 VOLTS
V = DROP IN CIRCUIT VOLTAGE (VOLTS)R = RESISTANCE PER FT OF CONDUCTOR (OHMS/FT) CURRENT = 56.818182 AMP (FOR SERIES LAMP2)I = CURRENT IN CONDUCTORL = ONE WAY LENGTH OF CIRCUIT (FT)d^2 = CROSS SECTION ARE OF CONDUCTOR (CIRCULAR MILS)K = RESISTIVITY OF CONDUCTOR METAL (CIR MIL-OHMS/FT) K = 12 FOR CIRCUITS LOADED TO MORE THAN 50% OF ALLOWABLE CARRYING CAPACITY K = 11 FOR CIRCUITS LOADED FOR LESS THAN 50% OF ALLOWABLE CARRYING CAPACITY K = 18 FOR ALUMINUM CONDUCTORS AT 30 DEG C.
To figure out which size unit is best for your cooling needs:1. Determine the square footage of the area to be cooled using the following formulas:
For square and rectangular rooms, multiply the length of the area by its widthFor a triangular area, multiply the length of the area by the width and divide by 2
Most rooms can be further divided into these basic shapes to determine the square footage.
100 to 150 9.3 to 13.9 5,000 One ton of capacity equals 12,000 Btu/h150 to 250 13.9 to 23.2 6,000 (also one Btu/h is equal to 0.293 watts so...One ton = 3.516 Kilowatts)250 to 300 23.2 to 27.9 7,000
300 to 350 27.9 to 32.5 8,000
350 to 400 32.5 to 37.2 9,000
400 to 450 37.2 to 41.8 10,000
450 to 550 41.8 to 51.1 12,000
550 to 700 51.1 to 65.1 14,000
700 to 1,000 65.1 to 93.0 18,000
1,000 to 1,200 93.0 to 111.5 21,000
1,200 to 1,400 111.5 to 130.1 23,000
1,400 to 1,500 130.1 to 139.4 24,000
1,500 to 2,000 139.4 to 185.9 30,000
2,000 to 2,500 185.9 232.4 34,000
3. Make any adjustments for the following circumstances:
If the room is heavily shaded, reduce capacity by 10 percent.If the room is very sunny, increase capacity by 10 percent.If more than two people regularly occupy the room, add 600 BTUs for each additional person.If the unit is used in a kitchen, increase capacity by 4,000 BTUs.
Many people buy an air conditioner that is too large, thinking it will provider better cooling. However, an oversized air conditioner is actually less effective — and wastes energy at the same time. Air conditioners remove both heat and humidity from the air. If the unit is too large, it will cool the room quickly, but only remove some of the humidity. This leaves the room with a damp, clammy feeling. A properly sized unit will remove humidity effectively as it cools.
If the shape of your room is other than square or rectangular, ask your sales associate to help you determine the square footage.
2. Using the square footage and the chart below, determine the correct cooling capacity. Cooling capacity is measured in British thermal units (BTUs) per hour.
Area To Be Cooled (square
feet)
Area To Be Cooled (square meter)
Capacity Needed
(BTUs per hour)
Consider where you install the unit. If you are mounting an air conditioner near the corner of a room, look for a unit that can send the airflow in the right direction.
Determine type of
occupancy
Compute the total VA of all luminaries installed for genera-purpose lighting
Calculate general lighting
load
Determine other loads
Compute the total VA of all luminaries installed for genera-purpose lighting
General Lighting Load: PHASESquare footage of the following [ 1 ] [ 2 ] 0Kitchen-small appliance circuits [ 3 ] [ 4 ] 0Laundry brarnch circuits [ 5 ] [ 6 ] 0
Total demand for general lighting loads = [ 12 ] #VALUE!
Load name, kva rating, volts [ 14 ]Load name, kva rating, volts [ 15 ]Load name, kva rating, volts [ 16 ]Load name, kva rating, volts [ 17 ]Load name, kva rating, volts [ 18 ]Load name, kva rating, volts [ 19 ]
Subtotal of fixed appliances[ 20 ]If 3 or less fixed appliances take @ 100% = [ 21 ] [ 21 ]If 4 or less fixed appliances take @ 75% = [ 23 ] [ 24 ]
[ 25 ] [ 26 ][ 27 ] [ 28 ]
[ 29 ] [ 30 ]
Largest Motor = 0 [ 31 ] 0Total VA Demand = [ 33 ] [ 34 ]
VA /240 = amps = [ 35 ] [ 36 ]
Service OCD and Minimum Size Grounding Electrode Conductor = [ 37 ] [ 38 ]
[ 39 ] [ 40 ]
Subtotal of general lighting load per NEC Section 220.52Subtract 1st 3000VA per NEC Table 220.42
Remaining VA times 35% per NEC Table 220.42
Fixed Appliance Loads (nameplate or NEC FLA of motors) per NEC Section 220.53
Other Loads per NEC section 220.14Electric Range per NEC table 220.55 (neutral @70% per NEC section 220.61)Electric Dryer per NEC table 220.54 (neutral @70% per NEC section 220.61)Electric heat per NEC Section 220.51
Omit smaller load per NEC Section 220.60Air conditioning per NEC Section 220.14(a)
x 25% per NEC Section 430.24 =
AWG per NEC Tables 310.15 (b)(6) and 310.16 for neutral =
Load # 4 Hermetic Refrigerated Motor-Compressor LoadThis load is derived by multiplying full load VA of compressor by 125%
Load # 5 Motor LoadThe VA rating of each motor is converted from full load amp (FLA) to VA by taking the FLA values from NEC table belowTable 430.248 = For single phase motorTable 430.250 = For three phase motor
The FLA for other than motor for low speed refer toNEC Sec 430.6(A)(1)
Requirement for more than one motor for calculating the
The VA rating of the largest motor must be calculated by multiplyingthe motor's VA by the system voltage and then increasin the total by 25%
Load # 1 Cont Load Non-Cont LoadGeneral Lighting : per Area x VA 0 per actual quantity 0Show window 0Lighting track 0Inductive load 0Sign and outline load 0