Electric panel replacement questions...

I have 225 Zinsco brand main panel inside my garage, which has a big 225 "MAIN" breaker on top and a "150" on the bottom. I believe the "150" leads to either the Bryant sub panel (also in the garage running kitchen & HVAC) OR to the exterior GE sub panel, which primarily runs my pool equipment & some exterior lighting is connected to a panel with one big 225 "MAIN" breaker as well as my meter from the utility co.

Home Inspector suggested replacing the Zinsco, which apparently is susceptible to tripping/fire issues as well as the exterior GE due to it's rust issues.

That said, what is the benefit and/or difference between having a 225 "MAIN" breaker on the main panel in the garage and the exterior 225 "MAIN" breaker? Would you keep one on the new main panel in the garage, upon replacement?

 

Some utilities require the main outside in which case you would not need one in the interior panel.
Geo

 

It looks to me like your MAIN is adjacent to the meter and that it feeds the big inside Zinsco panel. It also looks like the MAIN by the meter feeds the subpanel to the right of it, but that may be a problem. It's hard to say without having the covers removed, but I suspect you have some double lugging violations inside the MAIN disconnect box next to the meter.

The 225A MAIN outside at the meter probably has the added benefit of making the service compliant with the NEC. You don't need a main breaker on the inside panel.

Assuming you need the main breaker at the meter, I would not also have one in the inside panel. It is optional and you can have one there, but isn't required.

I also seriously doubt you need a 225 amp service. You should do a load calculation to verify it, but few homes need more than a 200 amp service.

 

Thanks!

Per code, I don't believe I'm required to have the interior MAIN too; I was just wondering, if there's any benefit to having it in addition to the exterior MAIN.

FWIW, the exterior MAIN appears to control both the Zinsco & the Bryant PLUS the pool equipment & some exterior lighting, whereas the interior MAIN appears to control the Zinsco, which it is attached to & the Bryant but NOT the pool & exterior lighting.

 

I'd be interested in seeing pictures of both the main disconnect and the subpanel next to it with the covers off.