A store 50 ft. by 60 ft., or 3000 sq. ft., has 30 ft. of show window. There are a total of 80 duplex receptacles. The service is 120/240volt, singlephase 3wire service. Actual connected lighting load, 8500 voltamperes.
Calculated Load (See 220.40) 

Noncontinuous Loads 

Receptacle Load (see 220.44) 


14,400 voltamperes 

10,000 voltamperes 

2200 voltamperes 

12,200 voltamperes 
Continuous Loads 

General Lighting[*] 

3000 sq. ft. at 3 voltamperes per sq. ft. 
9000 voltamperes 
Show Window Lighting Load 

30 ft. at 200 voltamperes per foot 
6000 voltamperes 
Outside sign circuit 1200 volt amperes [see 220.14(F)] 
1200 voltamperes 
Subtotal 
16,200 voltamperes 
Subtotal from noncontinuous 
12,200 voltamperes 

28,400 voltamperes 
[*] In the example, 125 percent of the actual connected lighting load (8500 VA x 1.25 = 10,625 VA) is less than 125 percent of the load from Table 220.12, so the minimum lighting load from Table 220.12 is used in the calculation. Had the actual lighting load been greater than the value calculated from Table 220.12, 125 percent of the actual connected lighting load would have been used.
Minimum Number of Branch Circuits Required
General Lighting: Branch circuits need only be installed to supply the actual connected load [see 221.11(B)].
8500 VA x 1.25 = 10,625 voltamperes 

10,625 voltamperes ÷ 240 volts 


The lighting load would be permitted to be served by 2wire or 3wire, 15 or 20ampere circuits with combined capacity equal to 44 amperes or greater for 3wire circuits or 88 amperes or greater for 2wire circuits. The feeder capacity as well as the number of branchcircuit positions available for lighting circuits in the panelboard must reflect the full calculated load of 9000 VA x 1.25 = 11,250 voltamperes.
Show Window
6,000 VA x 1.25 = 7500 VA 

7500 voltamperes ÷ 240 volts 


The show window lighting is permitted to be served by 2wire or 3wire circuits with a capacity equal to 31 amperes or greater for 3wire circuits or 62 amperes or greater for 2wire circuits.
Receptacles required by 210.62 are assumed to be included in the receptacle load above if these receptacles do not supply the show window lighting load.
Receptacles
Receptacle Load: 

14,400 voltamperes ÷ 240 volts 


The receptacle load would be permitted to be served by 2wire or 3wire circuits with a capacity equal to 60 amperes or greater for 3wire circuits or 120 amperes or greater for 2wire circuits.
Minimum Size Feeder (or Service) Overcurrent Protection [See 215.3 or Section 230.90]
Subtotal noncontinuous loads 
12,200 voltamperes 
Subtotal continuous load @ 125% 

16,200 VA x 1.25 
20,250 voltamperes 
Total 
32,450 voltamperes 
32,450 VA ÷ 240 volts = 135 amperes 
The next higher standard size is 150 amperes (See 240.6).
Minimum Size Feeder (or Service Conductors) Required [See 215.2, 230.42(A)]
For 120/240volt, 3wire system: 32,450 voltamperes ÷ 240 volts = 135 amperes.
Service or feeder conductor is 1/0 Cu per 215.3 and Table 310.16 (with 75°C terminations).