Hot Topics: Why Is There Goo Behind This Breaker?

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Get all your ducks in a row for some electrical DIY, and then find out that the original electrician did something you weren’t expecting. What’s this stuff he used? Does he know more than you? Maybe you’ve skipped a step for years without knowing it – or maybe not. The Forum identifies the substance.

Original Post: Breaker goop?

slade8200 Member

As I'm replacing/moving some breakers, I noticed on the back of the original ones there's this charcoal-colored goop on the contact area. Is this supposed to be there?

Highlights from the Thread

pcboss Forum Topic Moderator

That looks like the breaker has taken too much heat and melted. Compare that to a new breaker to see how it should look.

slade8200 Member

It's not melted plastic. It's like a grease.

PJmax Group Moderator

Some electricians apply Penetrox, which is an anti-corrosion grease, to aluminum bus bars in panels. Although not required and is not detrimental to the performance of the breaker... that is way too much on those breakers. There should only be a very thin film.

If you intend to clean the bus bars, be sure to turn off the main before touching them. Wouldn't hurt to check them with a meter to confirm they are dead.

CasualJoe Member

I also think that is anti-oxidant grease and it should have never been used. Anti-oxidant is used to protect aluminum wire connections from oxidizing. The aluminum bus bars in a load center/panel board are tin plated, the anti-oxidant does nothing except make a huge friggen mess.

slade8200 Member

Hahaha. OK, thanks.

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