Load Calc, diversity of use?

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sw_ross

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Scenario- older building, main level is storefront with typical daytime business hours. Upper level is older outdated offices that haven't been in use for years.

Owner wants to convert upper level into her living space. She would operate the store during day. During evening she would close store and head upstairs to her living space.

To do a load Calc for this building I would think that there would be some sort of "diversity of use" that could be taken advantage of due to the fact that the owner doesn't plan to use the upper living space at the same time that she'll be using the main level store space?

220 doesn't address this specifically that I can see.
Am I missing something here?

Thanks!
 
sw_ross said:
Scenario- older building, main level is storefront with typical daytime business hours. Upper level is older outdated offices that haven't been in use for years.

Owner wants to convert upper level into her living space. She would operate the store during day. During evening she would close store and head upstairs to her living space.

To do a load Calc for this building I would think that there would be some sort of "diversity of use" that could be taken advantage of due to the fact that the owner doesn't plan to use the upper living space at the same time that she'll be using the main level store space?

220 doesn't address this specifically that I can see.
Am I missing something here?

Thanks!
Click to expand...
Potentially you could take advantage of the allowance in the code for mutually exclusive loads IF you had some interlock preventing the use of both loads simultaneously. not real likely in this scenario. Just run the numbers and see what comes out. Her living space probably won't amount to all that much.
 
Bob is talking about 220.60. I have always treated it in the way Bob describes, meaning that you need some type of interlock to prevent both loads from being on at the same time. But looking at the words of this article, it says "likely," not "impossible due to an interlock." So some manner of judgment is needed here. For example, the owner may close the store for a lunch break, and go upstairs to run the dishwasher and laundry machines. So you can't assume that the residence draws no power during the day.
 
What if, down the road for some reason, the owner decides she no longer wants to run the store and hires someone to do it while she stays upstairs at home?

If a diversity allowance was used to size the service, that service would now be undersized. I doubt she would even think about upgrading the service before she decided to stay upstairs.
 
K8MHZ said:
What if, down the road for some reason, the owner decides she no longer wants to run the store and hires someone to do it while she stays upstairs at home?

If a diversity allowance was used to size the service, that service would now be undersized. I doubt she would even think about upgrading the service before she decided to stay upstairs.
Click to expand...

The code does not require that you consider potential future changes.
 
I wouldn't try to add a diversity factor. Not sure what kind of store this is, but if it's got things like refrigeration, that will be on 24-7. Signs and other lighting, heat, ac will all be 24-7 also. Believe me, I'm the first one to complain about nec load calcs and trying to find work arounds, but I don't think this is a good idea.
 
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