I have an old electrical panel. Some of the circuits were flickering. When I checked the breaker to the associated circuit I found that the bus bar had "porous" looking buildup of metal at the location. See photo showing two arced bus bar sections. I can also still hear some occasional tiny sizzling/arcing noises coming from the breakers but don't know which ones are making the noise.

Can the metal buildup be filed down to the bare metal making the slot reusable?

I saw a bus bar replacement at home depot for $60. Is it worth time and money to replace this or should I be looking for someone to replace/upgrade the entire panel?

The subpanel has the copper ground connecting to the ground bar in the main panel. Is this OK?

Any comments on the rest of the panel? It looks like someone added a transformer in there with wire nuts

homicidal service panel

Looking at the comments now I'm worried. How much should it cost to upgrade my old 100 AMP to a new 200 AMP main?

If I put a new box in, how do you extend any short wires? wire nuts? a junction box under the house in the crawl space?


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    If you saw this bus online could you post a link? FWIW I won't work on circuits and breakers in any Zinsco panel. 20 years ago my parents bought a house with a Zinsco panel, I immediately gifted them a new panel. Commented May 26, 2020 at 21:50
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    Zinsco panels were notorious for causing fires because of bad connections to the bus bars. Replace the panel completely.
    – JRaef
    Commented May 26, 2020 at 22:04
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    You really need to think about replacing that panel as soon as you can. The arcing and sizzling sounds are scarier than gunshots and for a good reason. Those panela are fire starters.
    – JACK
    Commented May 26, 2020 at 22:49
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    Here's a thought: filing the bus bar down to get a smooth surface will make the bus bar thinner which means that the breaker's press-fit clamp will have an even worse connection than it does now (it relies on pressure to make a good, tight fit). Because the fit will be looser, instead of tighter, you'll end up with even more arcing. At best, you'd need AFCI breakers to protect your house and yourself against that. They probably don't make AFCI breakers for Zinsco panels. At worst, even with AFCIs, you'll start a fire and be replacing the whole house.
    – FreeMan
    Commented May 27, 2020 at 11:58
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    You really need to replace the panel. Sorry, but Zinsco are bad bad panels. Where I live you can't even get insurance on a house with a Zinsco panel. Sometimes the breakers "weld" themselves to the buss bar, sometimes they don't trip when they are supposed to. Replacement breakers are notoriously expensive. Commented May 27, 2020 at 15:56

1 Answer 1


No, cleaning the bus is not acceptable. Never seen a replacement bus for Zinsco panels. The existing breakers reportedly have 1300 series aluminum alloy that is not suited for non-bolted connections like the connections in the old breakers. A replacement bus to be safe would need to also have replacement breakers, that start at $30 for a single pole 20A breaker, and a 2p30 is $65. The math starts to get rough, and then would be worried you might not end up with a quality install anyway.

The ground in a subpanel should be connected to the ground in the panel feeding it, the neutral in the sub should be isolated from the ground in the subpanel.

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