calculation per 220.31a

[bill addiss]

Posted for jakel:

He'd like to find out what the general consensus for a calculation in accordance with 220.31a would be? In "a" it states that no ac or heat to be installed would this mean that there can not be any ac or heating in the load calculation? In "b" it states that when ac or heating is to be installed.

I have a contractor who wants to use this calculation but after reading the section I am not sure which of the two sections he would use. He is adding a pool heater to the service but has existing ac and heat. He wants to know which section applies 220.31a or 220.31b.

service is boarder line and I am not sure which would apply after reading the section. Any help you can give is appreciated.

Thanks
(jakel)

 

[pierre]

Re: calculation per 220.31a

Bill

If he is going to add just the pool heater to an existing service, I would use 220.31(A) for calculation purposes. Don't forget to use either the heat or A/C load in the calculation, whichever is larger as per (4).

Pierre