Demand factors for mobile home parks

[bdresman]

People want to bring in new homes to our park with higher rated panels than the pedestal has, so they want to upgrade the pedestal. Here is an example.

We have 3 homes on a 150A distribution breaker. A developer wants to bring in a home with a 100A panel. NEC article 550-22 suggests that with 3 homes we can use a demand factor of 0.44 giving each home capacity for 113A. So the answer would be yes.

I spoke with our local Building Dept who said that the sum of the pedestal breakers should not exceed the rating on the distribution breaker. So the answer would be no.

Which one is right?

 

[Dennis Alwon]

To the OP- I would call an electrician in to appraise the situation as we do not have enough info from you and this site is for professional electricians and the related industry.

I am closing this thread, in accordance with the Forum rules. This Forum is intended to assist professional electricians, inspectors, engineers, and other members of the electrical industry in the performance of their job-related tasks. However, if you are not an electrician or an electrical contractor, then we are not permitted to help you perform your own electrical installation work.


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[Dennis Alwon]

I have been reassured that the op is not doing the work but trying to get info as to what is required.

 

[Dennis Alwon]

Not sure what code you are under but this is the 2011

550.31 Allowable Demand Factors. Park electrical wiring systems shall be calculated (at 120/240 volts) on the larger of the following:
(1) 16,000 volt-amperes for each mobile home lot
(2) The load calculated in accordance with 550.18 for the largest typical mobile home that each lot will accept It shall be permissible to calculate the feeder or service load in accordance with Table 550.31.

No demand factor
shall be allowed for any other load, except as provided in this Code.

Table 550.31 is the same table you refer to.

 

[GoldDigger]

Not sure what code you are under but this is the 2011
Table 550.31 is the same table you refer to.

FWIW, the 2011 code provides (550.32(C)) that the pedestal service equipment (not the overcurrent device) shall not be smaller than 100A (regardless of calculated load or main panel rating of the home), so the park owner may want to upgrade at least all three of the pedestals on that distribution breaker while he is at it. The existing ones are presumably grandfathered, but this might be a good time to do the work on the other two. And in fact, the AHJ might argue for it.