Is there a minimum size for an apartment feeder?

Mr. Serious

Mr. Serious

Senior Member
Location
Oklahoma, USA
Occupation
Electrical Contractor
I got dragged into this situation where a landlord was trying to replace meter cans on his 4-apartment house, and the city and inspector won't let him only replace the meter cans because the 4 individual services were originally only 40 amps each, and he wants to stay with that. Of course, I know that dwelling units now require minimum 100A service, but it doesn't make a lot of sense for these particular units. All appliances are gas and they want to keep it that way.

To avoid having to run all new service wires and put 4 new panels, I suggested bringing it all under one service, and splitting off 4 feeders to the apartments. When doing it that way, if the load calculation comes up OK, would it be prohibited by code to re-use the existing 40-amp services, but make them (4) 40-amp feeders instead? It seems small for an apartment feeder, but these are small apartments without laundry facilities and I don't know if there is some minimum size require by code.

I know that equipment grounding conductors would likely have to be added and grounds separated from neutrals in the existing main panels which would become sub-panels.

I'm going to do a load calculation today and see how it comes out.
 
Mr. Serious said:
I got dragged into this situation where a landlord was trying to replace meter cans on his 4-apartment house, and the city and inspector won't let him only replace the meter cans because the 4 individual services were originally only 40 amps each, and he wants to stay with that. Of course, I know that dwelling units now require minimum 100A service, but it doesn't make a lot of sense for these particular units. All appliances are gas and they want to keep it that way.

To avoid having to run all new service wires and put 4 new panels, I suggested bringing it all under one service, and splitting off 4 feeders to the apartments. When doing it that way, if the load calculation comes up OK, would it be prohibited by code to re-use the existing 40-amp services, but make them (4) 40-amp feeders instead? It seems small for an apartment feeder, but these are small apartments without laundry facilities and I don't know if there is some minimum size require by code.

I know that equipment grounding conductors would likely have to be added and grounds separated from neutrals in the existing main panels which would become sub-panels.

I'm going to do a load calculation today and see how it comes out.
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Have you checked your STATE building code requirements? Should be a section for maintenance and/or repair.
Here you would NOT be required to bring up to current code standards.
Property owners have to be able to maintain.

You did not state what triggered this, so I am just assuming maintenance...before failure situation.
Read the section again on service sizing, apartments are not single family dwellings.

If you cannot figure out on your own, call state building official office and walk them through what you are trying to do and what you are being told on the local level.

Doubtful a load calc will help...trying to squeeze into a 40A feeder with current 220 calcs not likely.
 
He should not be forced to upgrade for making a repair. Are they changing old "A" base meter sockets so they can put in new meters or smart meters?
 
They're changing the meter sockets because they were the old-style cans, the tall rectangular ones with the window in front, and parts are no longer available so the utility asked for them to be changed. I believe the meters themselves were already somewhat modern and they fit into the old cans.
 
I have talked with everyone again and figured it out. The inspector misunderstood the scope of the work. The main part of the work was just to change meter cans at the power company's request. Upon understanding that, the inspector says he will not require any further upgrades, except to make sure there are two ground rods and increase the wire size in the riser to 2/0 copper, which is the minimum size approved by the power company.
 
Mr. Serious said:
I have talked with everyone again and figured it out. The inspector misunderstood the scope of the work. The main part of the work was just to change meter cans at the power company's request. Upon understanding that, the inspector says he will not require any further upgrades, except to make sure there are two ground rods and increase the wire size in the riser to 2/0 copper, which is the minimum size approved by the power company.
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Good that he was reasonable and it worked out.
 
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