100 amp service change

[tbakelis]

Hi All,

I have a question regarding changing out a residential single family service. I do a ton of overhead 100A to 200A and even underground 100A to 100/125A depending on what the utility co will give us based on existing lines.

He has an existing 100A federal pacific underground service. Just a 100A breaker feeding a sub panel in garage. No additional space for circuits at main. My customer wants to change it out because of Federals being junk. PG&E is only allowing him to stay at 100A unless he wants to spend 10K plus to upgrade vault.

My question is.... If I install a 100 amp meter main that has 16 space/24 circuits.... Can I put a 100 breaker in that panel for sub panel now that there are all these spaces for additional circuits? Do I have to downsize the sub panel breaker to like an 80A to pass inspection.

Thanks,

Ted

 

[mbrooke]

Does the sub really need 100 amps?


They have feed through lug panels if that helps.


One a side note, if the utility can see the load calcs and zoning you might get away with a 200amp service since the theory being the service will never go over 100amps because no new loads were added or will be. Of course the poco has to agree to this but it might be worth mentioning to them.

 

[kbsparky]

.... If I install a 100 amp meter main that has 16 space/24 circuits.... Can I put a 100 breaker in that panel for sub panel now that there are all these spaces for additional circuits? ...

I would, if the loads have not changed significantly.

... Do I have to downsize the sub panel breaker to like an 80A to pass inspection....

I would not think so, but your mileage may vary, depending on your inspector-critter. :roll:

 

[ActionDave]

I don't see any problem other than I can buy a 200A panel for the same price as a 100A and have more room to work. POCO where I live does not care a bit what size panel is on the the customer side of the meter as long as no new, really big loads are added.

 

[GerryB]

Does the sub really need 100 amps?


They have feed through lug panels if that helps.


One a side note, if the utility can see the load calcs and zoning you might get away with a 200amp service since the theory being the service will never go over 100amps because no new loads were added or will be. Of course the poco has to agree to this but it might be worth mentioning to them.

I had a very similar job last month. I could not find a feed through panel less than 200amps, and expensive. What I did was buy a main lug GE 8/16 panel, put the(in my case)125amp breaker in top two slots, either side, and they have a retainer clip for that panel to make it a legal main. Fed the sub-panel from the main lugs and had spots left. I needed to put the dryer breaker in there.

 

[tbakelis]

I've installed a 200 amp with the feed through lugs but never 100A. I'll have to check with my distributor to see if the stock one. Anyone know of a square D product that would be 100 amp meter main with feed through and spaces for circuits? Thanks for all the help!

 

[kbsparky]

I have used a 200 Amp meter/main or feed-thru and changed the main breaker to a 100 Amp on some projects.

Same box, no muss, no fuss.

-KB

 

[Ponchik]

Do I have to downsize the sub panel breaker to like an 80A to pass inspection.

Thanks,

Ted

Where did you get 80Amp rule from? I have heard that before but the last two guys were not able to come up with a code section and/or reasoning.

PG&E usually allows a 125Amp panel on a 1.25" underground conduit with existing service conductor.

 

[ActionDave]

Where did you get 80Amp rule from? I have heard that before but the last two guys were not able to come up with a code section and/or reasoning.

PG&E usually allows a 125Amp panel on a 1.25" underground conduit with existing service conductor.

At one time you could tie 2AL or 4CU to a 100A breaker. Then table 310 something, something (B(7), is that right?) got changed and you had to use a 80 or 90A breaker if you were feeding a subpanel. Apparently houses were bursting into flames and people were fleeing their single family dwellings causing traffic jams on the freeways. Something had to be done.

 

[tbakelis]

Where did you get 80Amp rule from? I have heard that before but the last two guys were not able to come up with a code section and/or reasoning.

PG&E usually allows a 125Amp panel on a 1.25" underground conduit with existing service conductor.

Yeah, I told the customer this but pge shot the 125A down this time and said they have to stay at 100. Maybe they are getting greedier than they already are pushing for the customer to pay for upgrading the vault!!!

 

[jxofaltrds]

Have you performed a load cal?

http://www.mikeholt.com/freestuff-menu.php

Maybe if you can prove what you need rather than what you want you may get what you want.

Just a thought.

 

[electricguy61]

I've done a number of these underground panel changes with PG&E in the San Jose Area, including one last week.

Typically, PG&E will allow the upgrade to 125, but it depends on the load of the transformer feeding it. They would not allow me to put a 125amp breaker in a 200amp rated panel, on the theory I could later change out the breaker to the larger size.(????????)

The one I did last week, I used a Cutler Hammer MBE1224B125BTF panel with a feed through lug kit BRSF125, and for this one I changed the 125 amp main breaker to a 100amp (it was an emergency job, the old FPE meter base had melted down and I didn't have time to wait for PG&E to approve the upgrade to 125amp)

Anyway, never had a problem with the extra spaces in the new meter main. All that matters is the amperage of the main breaker.