dwelling unit calculations

[Mr. Spinosa]

I have a customer who has a double wide trailer and two other outbuildings on the same piece of property. The trailer is powered from the meter pack which has space for other breakers. Right now it has two other 125A double pole breakers which serve the other two buildings. Is there anything wrong with this?

How do you do a load calculation for three separate buildings that all use the same service? Is this even acceptable? I don't know of anything that would prohibit it.

This is what I did so far. I combined the calculations for the three separate buildings into one calculation and came up with a required service size which exceeds the size of the existing service. - I would however, like some confirmation that I am approaching this correctly.

One of the additional buildings is a dwelling the other is a tool shop; I am not sure how to categorize the tool shop.

 

[jxofaltrds]

I have a customer who has a double wide trailer and two other outbuildings on the same piece of property. The trailer is powered from the meter pack which has space for other breakers. Right now it has two other 125A double pole breakers which serve the other two buildings. Is there anything wrong with this?

How do you do a load calculation for three separate buildings that all use the same service? Is this even acceptable? I don't know of anything that would prohibit it.

This is what I did so far. I combined the calculations for the three separate buildings into one calculation and came up with a required service size which exceeds the size of the existing service. - I would however, like some confirmation that I am approaching this correctly.

One of the additional buildings is a dwelling the other is a tool shop; I am not sure how to categorize the tool shop.

Manufactured Home. Is the PC term now-a-days.

See red above.

 

[Smart $]

You're not giving us much to go on...

Does the tool shop do "work-for-hire" or a hobby shop? If a hobby shop, it is just considered an outbuilding AFAIK... classification can vary by local zoning, licensing, CoO, and such.

The calculations for the dwelling units are combined... not just the results added together... because demand can effect the result. For example, if each dwelling has two appliances, 75% demand factoring for 4 appliances would apply to the service (if both dwellings are mobile/manufactured homes, only 3 appliances are required for the 75% demand allowance).

The breaker ratings don't matter as long as they protect the connected feeders and equal or exceed the calculated load adjusted for continuous loading.