Residential Load Calculations

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MDA1705

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When can I use Standard or Optional Residential Load Calculations. Is there any section on the code that addresses the subjet.
Thanks for any help
Miguel:confused:
 
I would always perform the calculation both ways, and use the smaller value as my answer. I may choose to put more into the design than the smaller value, but that would be a design choice, not an NEC requirement.

Welcome to the forum.
 
200 amps will cover almost any normal 2,000 sq foot 3bd 2 bth 2 car garage. Now if you think it may need more then do it both ways. I would never offer less than 200
 
Why does a minimum standard provide optional methods? I guess we have the standard minimum and the optional minimum. Who knew two separate things could be the minimum at the same time...
 
I think the only NEC requirement is that if it comes out to more than 100 amps you must use the standard, which is kind of a pain because you have to do the calculation before you know whether or not you will be over or under 100 amps. I agree that most SFD services start at 200a just because there is usually not enough cost difference to worry about. Once you get into mult-family it becomes cost effective to go no more than you need.

Edit to add: 220.30 A
 
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I understood it that you can use either the standard or optional method for everything but your service neutral calculation...this must be done with the figures given via the standard method...so you have to end up figuring it both ways anyway...i could be wrong...
 
Residential Load calculations

Residential Load calculations

Thanks everybody for your responses.
My customer bought a huge H2X cross trainer spa (14.5' long), manufacturer recomends to use 2 50a breakers with (3)#6, The house have a 200a service with a 200a main breaker box. The building department requested the load calculations. Using the standard method I will have a 250amps demand load, while using the optional method I will be around 150 amps.
I am concern about the difference between both methods .
Please any advice will be appreciate .
Thanks

Miguel
 
i really dought you need to change the service. What is the totall max watts this tub would use. Might be high while heating first time but likely has more than 1 heater.

My place is about 2600 sq feet plus cottage 300 feet and large screen room for tub and pool table and doing fine on 200 amps. Never had it trip. (no its not a FPE)
 
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