HomeMy WebLinkAboutApproved Load Calcs.pdf ) (3 V ' ° —73111. 1 — 1E - OII1
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Standard Method for Dwelling Service Calculations
Worksheet for the EVITP
Using the Standard Method complete this worksheet to perform a service load
calculation. An example of standard loads is shown below.
3000 Sq. Ft. of Living Space 1-15 kW Electric Range
3-Small Appliance Branch Circuits 1- 5 kW Wall Mounted Oven
1- Laundry Branch Circuit 1- 3 kW Cooktop Unit
1 —4.2 kW Electric Dryer 1.6 kW 120 V Dishwasher`
1 —28A- 240V Central A/C Unit 1/3 HP Disposal — 120V
1-12A - 120V Under-Cabinet Microwave Oven 1/2 HP Compactor— 120V
1- 4kW Electric In-Floor Heat 2-1/4 HP Attic Fans — 120V
2—6kW Electric Baseboard Heat 1/3 HP Sump Pump — 120V
Level 2 EVSE—24A— 240 V
Step 1: Section 220.12— Lighting load for listed occupan ies. 1/
Op VA
Sq. ft. x3VA = gI
Step 2 : Section 220.52 —Small Appliance and Laundry load.
1 � °° Sq. ft. x3VA = Vic) VA
Appliances Circuits x 1500VA = VA
Laundry Circuit x 1500 VA = 1 VA
General Lighting Load = 99 00 VA
Step 3: Table 220.42 Apply demand factors to the general lighting load.
First 3000 VA at 100% = 3506 VA
Remainder at 35% ( x 0.35) = C O VA
Net Load = S,/ 0 VA
1
Step 4: 220.53— Demand Factor—Appliance Loads — Dwelling Units.
Sly WI'S/, _ /‘ do VA
= 1/ Q 0 VA
r /1 = CO VA
A c i/- = ( VA
cdryc✓c170k7 = 1 F`�'0 VA
= 0 VA
VA
VA
VA
Total = /a VA
75% of total; four or more appliances = / co VA
Step 5: 220.54—Clothes Dryer—The greater of 5 kW or nameplate value.
''IS C 0 kW Electric Dryer = o VA
Step 6: Table 220.55 Household cooking Equipment
C,v►5G. = tIS O C) VA
VA
VA
Total = '_t()-6 () VA
Step 7: Article 220.60 — Noncoincident Loads
Air conditioning
Ax Vx (#) = VA
A x V x (#) = VA
2
Electric Heat
A x V x VA
Ax Vx (#) = VA
Largest load = VA
Step 8: 220.50 —25% of largest motor FLA.
A x CA, 06 V x 25% = 0 0 VA
Remember that although the voltages shown in the tables in Article 430 indicate that
motors are rated for 115,230 and 460 Volts, Section 220.5(A) requires nominal voltages
of 120, 240 and 480 Volts to be used for load calculations.
Step 9: 220.14(A) Other Loads — EVSE
A x V x (#) = VA
Sum of Calculated Loads
Lighting, Sm. Appliance, Laundry (Step 3) = / G VA
Fastened in Place Appliances (Step 4) = 720 0 VA
Clothes Dryer (Step 5) = Cre r% VA
Cooking Equipment (Step 6) = 917C—C)0 VA
Noncoincedent Heat—A/C (Step 7) = VA
25% of Largest Motor (Step 8) = 7° O VA
Other Loads— (Step 9) = VA
Total Calculated Load = a-3 U c) VA
3
Step 10: Table 310.15 (B)(6) —Size the service and conductors.
' C' VA/ 240V = �� C(- Amps
Conductor Size CU AL
Step 11: Grounding Electrode Conductor—Table 250.66
GEC Size _ • (%' Cu AL
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