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-   -   rust on circuit breaker contact (http://www.diychatroom.com/f18/rust-circuit-breaker-contact-33311/)

xv144 12-07-2008 07:36 AM

rust on circuit breaker contact
 
I bought two used QO 60AMP circuit breakers to go from main to subpanel. One of the circuit breakers has a little bit of rust on one of the contacts that connects to the bar. Can I wire brush off the rust and use this safely, or should I discard it?

AllanJ 12-07-2008 09:50 AM

I would sand off the rust, being careful not to make the contact surfaces unsmooth or "unflat" and then use the breaker.

Yoyizit 12-07-2008 09:56 AM

At 60A, even "10 milliohms worth" of rust could cause some problems.

Since they're used. . .
get a copy of the trip curve for this breaker and find a way to test it. Maybe it's supposed to trip in 4 to 15 sec. @ 180A.

This kind of soldering gun
http://www.ted-kyte.com/3D/Pictures/Soldering%20Gun.jpg
may put out that much current.

A breaker that fails by not opening when it is supposed to open could cause serious problems.

jbfan 12-07-2008 10:42 AM

Can I ask how much you paid for the two used breakers?

xv144 12-07-2008 12:51 PM

Quote:

Originally Posted by jbfan (Post 195100)
Can I ask how much you paid for the two used breakers?

Sounds like a set up, but I'll bite. $9 each plus $3 for shipping.

Yes, new is better and safer, but funds were very tight for this project. Budgeted $200 and spent $300+.

xv144 12-07-2008 12:53 PM

Quote:

Originally Posted by AllanJ (Post 195079)
I would sand off the rust, being careful not to make the contact surfaces unsmooth or "unflat" and then use the breaker.

It was only a tiny bit of rust. 1/4 of one side, of one connector. I used some fine sandpaper and it removed all the rust.

Gigs 12-07-2008 02:55 PM

Come on, sanding corroded breaker contacts?

If it's corroded on the outside it may very well be corroded on the inside.

Your safety is not worth saving $10.

Quote:

get a copy of the trip curve for this breaker and find a way to test it. Maybe it's supposed to trip in 4 to 15 sec. @ 180A.
Even if he tests the thermal trip he won't know if the magnetic works right with a dead short, and a dead short to test it is a somewhat destructive test. Even if it works right once or twice it may not work the next time.

Buying used breakers seems to me like buying used condoms... A really bad idea.

Yoyizit 12-07-2008 03:47 PM

Quote:

Originally Posted by Gigs (Post 195192)
If it's corroded on the outside it may very well be corroded on the inside.

Your safety is not worth saving $10.
See below.
Even if he tests the thermal trip he won't know if the magnetic works right with a dead short, and a dead short to test it is a somewhat destructive test. Even if it works right once or twice it may not work the next time.
Failure analysis assumes that if you have X consecutive successful trials, it will fail on X + 1.

If the cost of a breaker can be equated to an insurance premium, and the new breaker costs $20 and is 99% reliable, your expected "loss", in that you might get a bad breaker, is 1% of $20 = 20 cents.
If a used breaker is 50% reliable, you should pay no more than (1/0.5) x 20 = 40 cents for it, for taking on the same amount of risk.

Insurance companies don't like paying out fire claims.
My concern would be that if they discovered a used breaker, and this breaker can even be remotely linked to the cause of a fire, then they will deny coverage.
They are certainly motivated to spend a few hours investigating in order to save a few kilobucks.
I might even agree with them, in denying coverage, in this case. The homeowner has a Duty of Care and is supposed to exercise Due Diligence in protecting his insured house from harm.

rgsgww 12-07-2008 05:20 PM

Its rusted, used, I mean come on? Go out and buy a new one. Geez...:thumbdown:

Is it worth it to save a few bucks...come back after work to find your house burning?

Speedy Petey 12-07-2008 05:27 PM

NINE dollars??!?? Do you realize how much they are new??? Let's see....well, here's one brand new online for, hmmmm.....$20.
http://www.amazon.com/gp/product/B000H5ZWVA

Sorry to be so frank, but if the $22 difference in cost is an issue you should not have even started this project in the first place!

I mean, what's done is done, we are beating a dead horse here, but I find this disturbing.

jerryh3 12-07-2008 05:32 PM

Quote:

Originally Posted by Speedy Petey (Post 195231)
NINE dollars??!?? Do you realize how much they are new??? Let's see....well, here's one brand new online for, hmmmm.....$20.
http://www.amazon.com/gp/product/B000H5ZWVA

Sorry to be so frank, but if the $22 difference in cost is an issue you should not have even started this project in the first place!

I mean, what's done is done, we are beating a dead horse here, but I find this disturbing.

They're only $15.50 at HD.

DUDE! 12-07-2008 05:35 PM

the first time I read the responses here, I thought they were harsh, gave them some further thought, and realized the reasoning behind them. We're not talking getting some car parts from the junk yard,( I've certainly done my share) You're talking someone's safety. Good job. To the OP, I've been there, done that, bite the bullet and get new breakers too much at stake. And to Gigs, your last line says it all.:laughing:

xv144 12-07-2008 08:02 PM

OK. You talked me into buyin a new breaker. Now we can all sleep tonite.

Gigs 12-08-2008 05:28 PM

Quote:

Originally Posted by Yoyizit (Post 195203)
breaker can even be remotely linked to the cause of a fire, then they will deny coverage.
They are certainly motivated to spend a few hours investigating in order to save a few kilobucks.

Insurance companies are not going to try to nitpick their way out of a claim. If they did this, they would never pay a claim for an electrical fire. How many fires do you think are caused by 100% to-code wiring... nearly 0. The insurance companies don't like paying claims, but if you are missing a house due to a fire, they are going to pay in all but the most negligent of cases.

Of course this doesn't take away from used breakers with rust on them being a very bad idea. :P

Yoyizit 12-08-2008 06:16 PM

Quote:

Originally Posted by Gigs (Post 195714)
Insurance companies are not going to try to nitpick their way out of a claim.

Who's to stop them?
http://www.google.com/search?hl=en&a...i=&safe=images


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