Idea for MSP “upgrade” without afoul of PG&E gas riser distance rules

[CT1!]

Hi All - While this isn’t directly related to Tesla energy, I see a lot of similar threads on related topics, but not this scenario discussed, and I’d like to get feedback on. I have a TM3 and am getting solar installed, and would like to make it easy to upgrade to a powerwall sometime in the future. More on the situation:

1) I already have 200 amp underground service, and the meter and panel agree.
2) I have a NEM 2 solar installation coming up in the next few months. I do not want to do ANYTHING to jeopardize my NEM 2 status.
3) I have a Zinsco MSP on the outside of my garage, would like to upgrade it. Since I’m in CA, it’s in the same box as the meter.
4) The gas riser is clearly too close to the MSP.
5) I have 2 sub-panels, and the solar contractor is planing for the solar connection to come into a newer, modern sub-panel inside the garage, so as not to touch anything on the existing MSP.

Here’s my idea: Install a new (probably SPAN) “sub-panel” inside the garage, directly on the backside of where the existing ZInsco MSP is. Remove all of the curcuits from the Zinsco MSP and route them into the new SPAN sub-panel and leave only a single 200 amp breaker in the existing MSP, feeding the SPAN panel directly behind it. Install the solar into this new SPAN sub-panel.

I *think* this would allow me to effectively “upgrade” my MSP, improve safety by having every working load behind a modern breaker, have a cleaner solar install, and make it easier to add a powerwall, a generator, etc in the future, cost less than a full MSP replacement, and not run afoul of any of the PGE rules.

Am I right? Is this a good idea?

Thanks!

 

[wwhitney]

Remove all of the curcuits from the Zinsco MSP and route them into the new SPAN sub-panel and leave only a single 200 amp breaker in the existing MSP

The main difficulty is that many of these existing combo meter/main/distribution panels have no code compliant way to supply a 200A feeder. Often you are limited to a 100A or 125A feeder.

Cheers, Wayne

 

[holeydonut]

The main difficulty is that many of these existing combo meter/main/distribution panels have no code compliant way to supply a 200A feeder. Often you are limited to a 100A or 125A feeder.

Cheers, Wayne

I'm kind of confused, what CT1! is doing is what is on my house. I have a 200A underground service where the meter-socket/main panel just has a 200A breaker slapped on the middle of the MSP busbar. The load side of this 200A breaker goes to the utility feeder of my Tesla Energy Gateway 2. Why would there be a situation where only a 125A breaker would be allowed for a 200A service entry?

PS, I agree get rid of the Zinsco where possible, and moving the gas riser could be easier/cheaper than trying to lift and shift the main service panel. Although I feel like a "like for like" replacement of the Zinsco should be possible without much hassle.

 

[wwhitney]

I'm kind of confused, what CT1! is doing is what is on my house. I have a 200A underground service where the meter-socket/main panel just has a 200A breaker slapped on the middle of the MSP busbar. The load side of this 200A breaker goes to the utility feeder of my Tesla Energy Gateway 2. Why would there be a situation where only a 125A breaker would be allowed for a 200A service entry?

In a 200A meter/main only, the load side of the main breaker has lugs that will accept conductors for a 200A feeder.

In most (all?) 200A meter/main/distribution panels, the load side of the main breaker is factory connected to the distribution busbars in a way that has not been listed for field modification. And the busbar stabs are typically only rated for 125A each. For some panels, there are 200A branch circuit breakers that can be used in certain locations; they take up 4 full spaces so that they can use two bus stabs per pole. Older panels or panels will less wiring space will not be listed for such branch circuit breakers, and so you can't supply a feeder larger than 125A.

Cheers, Wayne

 

[holeydonut]

In a 200A meter/main only, the load side of the main breaker has lugs that will accept conductors for a 200A feeder.

In most (all?) 200A meter/main/distribution panels, the load side of the main breaker is factory connected to the distribution busbars in a way that has not been listed for field modification. And the busbar stabs are typically only rated for 125A each. For some panels, there are 200A branch circuit breakers that can be used in certain locations; they take up 4 full spaces so that they can use two bus stabs per pole. Older panels or panels will less wiring space will not be listed for such branch circuit breakers, and so you can't supply a feeder larger than 125A.

Cheers, Wayne

Ohhhh dang ... so I think you're saying is that some main service panels can only accept a BR-style breaker... so only 125A would be available since they don't actually make 200A plug on neutral breakers.

In my case, I have a main service panel with a bolt-on "frame size" big-boy (SC2040M200PF main panel that has a 200A breaker shown below and a "subfeed lug kit" also shown below).

Is it Code-OK to just add those subfeed lugs directly on the busbar? I mean I'm kind of wondering why someone would even need to use the load side of a breaker instead of just tapping some conductors on a busbar that is protected by a 200A main breaker.

 

[CT1!]

Great info, thanks! Although I do wonder why this exists:

 

[CT1!]

Sorry, hit send too soon. I do wonder why this exists:

Zinsco 200 Amp 3 in. 2-Pole Replacement Main Breaker

Also, I’d need to do the math, but since I already have 2 sub-panels and would be adding a 3rd, I might be able to get away with leaving the 2 existing ones in the Zinsco panel, and feeding the new ”MSP replacement” with a 125A breaker…

Thanks,

Chris

 

[CT1!]

It’s interesting, one of the comments in the reviews of the breaker I linked says “Fit perfectly, like the 6 points of contact for each buss bar. Replaced Unicorn brand breaker that had only 3 points of contact.”

So, sounds like practically it would work, but is there still a question about code?

 

[wwhitney]

Great info, thanks! Although I do wonder why this exists:

Message appears blank after the above, are you trying to show a particular product? Make and model number?

Cheers, Wayne

 

[holeydonut]

Sorry, hit send too soon. I do wonder why this exists:

Zinsco 200 Amp 3 in. 2-Pole Replacement Main Breaker

Also, I’d need to do the math, but since I already have 2 sub-panels and would be adding a 3rd, I might be able to get away with leaving the 2 existing ones in the Zinsco panel, and feeding the new ”MSP replacement” with a 125A breaker…

Thanks,

Chris

IMO, Zinsco is a tarnished brand... IMO some insurance companies won't even insure them. I know it's usually a subset of certain panels that were bad, but good luck trying to explain that when the panel has caught fire and you can't determine a model number.

Non-Insurable Electrical Panels | Inside & Out Property Inspectors

Certain types of electrical panels are non-insurable because of the large number of claims related to electrical fires. Find out more here.

insideandoutpropertyinspectors.com

 

[cali8484]

The Zinsco brand is certainly tarnished and I have wondered about what is the back story. Did the Zinsco panels have manufacturing or design problems that caused fires? How did the panels get UL approval?

 

[BGbreeder]

The Zinsco brand is certainly tarnished and I have wondered about what is the back story. Did the Zinsco panels have manufacturing or design problems that caused fires? How did the panels get UL approval?

There are good videos and websites available via quick Google search, but here is a starter;

Zinsco Electrical Panel Hazards Zinsco Circuit Breaker Information

Zinsco Electrical Panel and Circuit Breaker Hazards, Failures, Inspection, Detection, Repair, Replacement History of Zinsco,Sylvania electrical panel hazards,distribution of Zinsco electric panels,how to identify Zinsco,Sylvania electric panel hazards,licensed electrician,sources of...

inspectapedia.com

TL-DR version they fail to protect circuits and have been known to catch fire. Your pre-purchase home inspection probably called it out.

 

[cali8484]

There are good videos and websites available via quick Google search, but here is a starter;

Zinsco Electrical Panel Hazards Zinsco Circuit Breaker Information

Zinsco Electrical Panel and Circuit Breaker Hazards, Failures, Inspection, Detection, Repair, Replacement History of Zinsco,Sylvania electrical panel hazards,distribution of Zinsco electric panels,how to identify Zinsco,Sylvania electric panel hazards,licensed electrician,sources of...

inspectapedia.com

TL-DR version they fail to protect circuits and have been known to catch fire. Your pre-purchase home inspection probably called it out.

Thanks for the link. It's easy to see how such article could have seriously damaged Zinsco's reputation and it's interesting to see the caveat "We do not have statistically solid data that supports an unequivocal argument to replace Zinsco electrical panels." buried in the article.