Feeder Sizing Multiple Units

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I have a question about the electrical design for a project I'm doing the mechanical on (because I am nosey and want to learn!).

It is a campground with clusters of cabins fed from a single meter. These "cabins" each have full kitchen, bath, HVAC systems. The electrician has it laid out so the owner is feeding a cluster of eight cabins from one utility meter. The meter is off a current transformer at the secondary of the utility transformer. The feeder from the transformer is to a 1200A main panel with a breaker and feeder to each cabin's own 200A panel. All single phase 120/240.

On his drawing the electrician sized the feed to the "main" panel using Article 220 Part IV Optional Method -- I thought this is just for multifamily dwellings. This is multiple single dwellings.

How should he have sized feeder and branches?
 

charlie b

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SinglePole said:
. . . Article 220 Part IV Optional Method -- I thought this is just for multifamily dwellings. This is multiple single dwellings.
It's a good question. I thought at first that the electrician was right. After reading 220 and 100 more carefully, I now agree with you. The Part IV method (specifically 220.84) applies to multiple dwelling units of a "multifamily dwelling unit." Article 100 defines that term as being a building with three or more dwelling units.

Welcome to the forum.
 

Dennis Alwon

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For all practical purposes these cabins should behave as a multifamily dwelling. Technically you are correct but I would not lose sleep over it. Go ahead shoot me.
 

benaround

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Arizona
What is table 220.84 for??

Dwelling,multifamily: a building that contains three or more dwelling units.

Table 220.84 Optional Calcs.

Demand factors for THREE or more Multifamily Dwellings.

To me that reads, three buildings or more of multifamily dwellings.
 
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