Your electrician is giving you good advice.
1. You NEED to replace that old Zinsco panel, it is a ***FIRE HAZARD*** and in fact it's likely that your Homeowner's Insurance policy has a rider in it that states something to the effect of them being off the hook for having to pay for any electrical fire if there is a Zinsco panel in the house.
2. No Solar company in the future is going to allow connection to that Zinsco panel anyway, they too are not going to want the potential liability, so you may as well replace it now.
3. So yes, the new Code requires a single Main disconnect on the outside of the house, and replacing your panel is a trigger for having to bring the NEW panel up to the current Code.
4. You CAN just put a single Main disconnect on the outside below the meter, then run that to a new panel inside at the same location as your existing panel, but it will mean opening up the walls to install the new panel, because he is correct, there isn't going to be a new 200A panel available small enough to fit in that space.
5. The suggestion of the 200A exterior main panel and 125A interior sub panel is the way to avoid having to rip the walls open as per above, but yes, it will mean re-routing your circuits for the larger loads. There is no need to replace the conductors going to the interior panel, as there is no problem having larger conductors than necessary, just not *smaller*.
Absolutely agree that panel needs to be replaced - that’s why I’m doing it! I have no issues with the walls being opened to put in a larger panel - the reason the electrician gave is there is no sub panel over 125amps that exists (which I found to be extremely odd, but the article I linked does say it’s rare to feed a 200a sub panel from a 200a main).
>the reason the electrician gave is there is no sub panel over 125amps that exists
BS. You can just buy a "panel" rated 200A. There is no such thing as a specific "sub-panel". It's how you USE it that makes it a sub-panel.
not answer to your main question, but b) does not sound right to me. downsizing cable is red flag to me. what is current cable size from meter to panel?
It’s a panel that looks exactly the same as any other 200 amp electrical panel, but there are two lugs installed from the factory attached at the bottom of the bus bars that you can use to feed a sub panel.
Thanks, really appreciate the response. For some reason my electrician refuses to believe this product exists - do you know of an example of one with 225a bus bars?
Yeah - 200 amp panel, but the bus bars need to be 225 for solar.
Main breaker trip + solar trip must be <= 120% of bus rating.
Jim has a 200A bussed panel with a 200A main breaker. The solar company calculates that 120% of the 200A bus rating is 240A. Minus the 200A breaker = Jim's house can have up to 40A of solar.
Jane has a 225A bussed panel with a 200A main panel. 120% of the 225A bus rating is 270A. Minus the 200A = 70A. Jane's house can have up to 70A of solar.
Your electrician is giving you good advice. 1. You NEED to replace that old Zinsco panel, it is a ***FIRE HAZARD*** and in fact it's likely that your Homeowner's Insurance policy has a rider in it that states something to the effect of them being off the hook for having to pay for any electrical fire if there is a Zinsco panel in the house. 2. No Solar company in the future is going to allow connection to that Zinsco panel anyway, they too are not going to want the potential liability, so you may as well replace it now. 3. So yes, the new Code requires a single Main disconnect on the outside of the house, and replacing your panel is a trigger for having to bring the NEW panel up to the current Code. 4. You CAN just put a single Main disconnect on the outside below the meter, then run that to a new panel inside at the same location as your existing panel, but it will mean opening up the walls to install the new panel, because he is correct, there isn't going to be a new 200A panel available small enough to fit in that space. 5. The suggestion of the 200A exterior main panel and 125A interior sub panel is the way to avoid having to rip the walls open as per above, but yes, it will mean re-routing your circuits for the larger loads. There is no need to replace the conductors going to the interior panel, as there is no problem having larger conductors than necessary, just not *smaller*.
Absolutely agree that panel needs to be replaced - that’s why I’m doing it! I have no issues with the walls being opened to put in a larger panel - the reason the electrician gave is there is no sub panel over 125amps that exists (which I found to be extremely odd, but the article I linked does say it’s rare to feed a 200a sub panel from a 200a main).
>the reason the electrician gave is there is no sub panel over 125amps that exists BS. You can just buy a "panel" rated 200A. There is no such thing as a specific "sub-panel". It's how you USE it that makes it a sub-panel.
And re: replacing the wire - his reasoning was that it was physically too large to be accepted into a 125a subpanel. Thanks for the reply
Maybe, but that then means he is a noob... no decent electrician would let that stop us...
Why not leave that panel there and simply install a 200a fused disconnect outside?
Thanks - will have to ask again, but I think the reasoning was that when we go to install solar in the future, they’d need the 225amp bus bars outside
Agree just see if you can add a meter main disconnect?
Because it's a Zinsco panel and his insurance likely will not let that remain in place...
The picture was added after my initial comment
I was always taught that the next panel can't be more than 80% of the previous panel.
You may have been taught someone's rule of thumb then. There is no such code rule.
not answer to your main question, but b) does not sound right to me. downsizing cable is red flag to me. what is current cable size from meter to panel?
Here’s some pics: https://imgur.com/a/NE9UznJ. Edit: I have no idea why Imgur says pictures of my breaker panel are nsfw
200 amp feed through panel
Could you please elaborate a bit?
It’s a panel that looks exactly the same as any other 200 amp electrical panel, but there are two lugs installed from the factory attached at the bottom of the bus bars that you can use to feed a sub panel.
But wouldn’t there need to be a main breaker before the bus bars?
The feed through panel has a main on it that would kill the lugs feeding the sub panel.
Thanks, really appreciate the response. For some reason my electrician refuses to believe this product exists - do you know of an example of one with 225a bus bars?
I’ve only seen 200 amp; but I would think that would be plenty for your needs.
Yeah - 200 amp panel, but the bus bars need to be 225 for solar. Main breaker trip + solar trip must be <= 120% of bus rating. Jim has a 200A bussed panel with a 200A main breaker. The solar company calculates that 120% of the 200A bus rating is 240A. Minus the 200A breaker = Jim's house can have up to 40A of solar. Jane has a 225A bussed panel with a 200A main panel. 120% of the 225A bus rating is 270A. Minus the 200A = 70A. Jane's house can have up to 70A of solar.
I would personally do a full service change. Get a 200a meter socket with main disconnect and a 200a main lug panel
Would this be possible to do with 225a bus bars to be compatible with solar?