sizing feeder

[tommyrice]

recently I read aproblem asking to calculate the volt ampre number required to be used in sizing the conductor and overcurrent device for a store 60' by 80' of which 400 sq. was used for storage.the answer they gave was 4400 sq at 3va=13200va plus 400sq at 1/4=100 for a total of 13300va.I would think it should be 13200 x 1.25=16500 plus 100 for a total of 16600va to size the feeder.what do you guys think?

 

[Dennis Alwon]

Calculation for sq. feet does not need 125% added to it.

 

[ceb58]

recently I read aproblem asking to calculate the volt ampre number required to be used in sizing the conductor and overcurrent device for a store 60' by 80' of which 400 sq. was used for storage.the answer they gave was 4400 sq at 3va=13200va plus 400sq at 1/4=100 for a total of 13300va.I would think it should be 13200 x 1.25=16500 plus 100 for a total of 16600va to size the feeder.what do you guys think?

Why do you think that? By your math you are adding 25% to the 13200 then adding the 100 to it.

 

[tommyrice]

sizing feeder

I was multiplying 13200 by 1.25 because i considered main lighting for store as a continuous load, then i added 100 va because 400 sq ' was used for storage.400 x 1/4 =100va.store area including storage space was 4800 sq '.

 

[ceb58]

I was multiplying 13200 by 1.25 because i considered main lighting for store as a continuous load, then i added 100 va because 400 sq ' was used for storage.400 x 1/4 =100va.store area including storage space was 4800 sq '.

And from a design stand point that is OK. But the NEC is not a design manual. 220.12 doesn't require an additional 25% added. But read the FPN it states that the values may not be sufficient. On a test they are asking what code requires which is a minimum number and a correct answer doesn't leave room for yours or my opinion as to a quality install.