Mutifamily Dwelling Unit Load Calc.
- Thread starter SJ
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- Location
- Lockport, IL
- Occupation
- Semi-Retired Electrical Engineer
Re: Mutifamily Dwelling Unit Load Calc.
You don't get to "double dip." When you calculate an individual unit, you add all the loads in that unit, and apply the demand factors that apply to a single unit. That tells you the feeder size and equipment ratings for that one unit. When you calculate a feeder or service to a set of two or more units, you add all the loads in all of the units (without first using any demand factors on the individual units), and then apply the demand factors for the multi-family dwelling.
You don't get to "double dip." When you calculate an individual unit, you add all the loads in that unit, and apply the demand factors that apply to a single unit. That tells you the feeder size and equipment ratings for that one unit. When you calculate a feeder or service to a set of two or more units, you add all the loads in all of the units (without first using any demand factors on the individual units), and then apply the demand factors for the multi-family dwelling.
Re: Mutifamily Dwelling Unit Load Calc.
charlie b thank you for your answer, but what brought to my attention is that on article 220.84(B) states that House Loads shall be calculated in accordance to with Part III of the article 220. I assume that they are applying the factor to one unit and then multiply this value by the number of units. After I think they apply the factor of table 220.84.
What do you think?
charlie b thank you for your answer, but what brought to my attention is that on article 220.84(B) states that House Loads shall be calculated in accordance to with Part III of the article 220. I assume that they are applying the factor to one unit and then multiply this value by the number of units. After I think they apply the factor of table 220.84.
What do you think?
bphgravity
Senior Member
- Location
- Florida
Re: Mutifamily Dwelling Unit Load Calc.
"House loads" are not the individual dwelling loads. They are the common loads for the building such as walkway lighting, etc...
"House loads" are not the individual dwelling loads. They are the common loads for the building such as walkway lighting, etc...
- Location
- Lockport, IL
- Occupation
- Semi-Retired Electrical Engineer
Re: Mutifamily Dwelling Unit Load Calc.
I think you are reading 220.84(B) backwards. Are you confused about the meaning of "house loads"? That phrase means the hallways, the lobby, the recreational room, and the other rooms that are used by all tenants. You add that load last. You first add all the loads in all the units, then apply Table 220.84, then you add the house loads.
I sent this in reply to a PM. But I'll repeat it here. I see that Bryan has already posted a similar comment.
I think you are reading 220.84(B) backwards. Are you confused about the meaning of "house loads"? That phrase means the hallways, the lobby, the recreational room, and the other rooms that are used by all tenants. You add that load last. You first add all the loads in all the units, then apply Table 220.84, then you add the house loads.
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