Corrosion in Electric Panel ... What to Do?

[hosspuller]

Folks,

Long story, short. A subpanel in the house has had water intrusion at some point and now it has corrosion. What should I do, if anything, to fix this.

Here's my suggestion ... Replace the panel. Install it on the wall with a space between the wall and the panel to fix the water intrusion problem. Separate the neutrals & grounds to comply with code. Finally, replace the breakers when money allows. you could do this a few breakers at a time. I would be concerned about the breaker internals being degraded like the other connections. You really want the breakers to work when needed... Bad things happen quickly if they don't

 

[kennyd]

Separate the neutrals & grounds to comply with code.

He can only do that IF he has or can run a 4th conductor between the two panels. It may not be possible/feasible.

 

[GPintheMitten]

Thanks guys for all your replies and sound advice.

I pulled a permit and will see what the local electrical inspector says. I'm pretty sure he will agree with you all to replace the panel. I also thought the neutrals should float separate from the ground on subpanels.

I suspect the water intrusion happened when this was the main.

I'll put up some plywood between the panel and the concrete wall, as well.

Thanks again.

 

[GPintheMitten]

He can only do that IF he has or can run a 4th conductor between the two panels. It may not be possible/feasible.

Ok, I will check that out.

 

[BIG DOOLEY]

Replace the panel/contents and correct the source of moisture. That panel is just a major accident waiting to happen. I would do it today, it will be money well spent.
Ken

And destroy the old one.

 

[wrooster]

And destroy the old one.

The old one has about 3 pounds of copper in it. Recycle it for money.

Wrooster

 

[Mace Canute]

......... I'm wondering if there is a solvent I could use to clean up the corrosion, or just leave it alone, or replace the whole panel...........

Considering the age of it and the fact that it isn't up to code at the present, I'd recommend replacing it. As others have said, the neutral and ground have to be separated in subpanels, etc and I believe you are not supposed to mount an electrical panel directly on a concrete wall if I'm not mistaken; something to do with condensation being a problem if you do that IIRC. I can't tell for sure but it looks to me like you have a couple of breakers with two conductors in them. If so, that's also against code IIRC...another reason to replace the panel with one that has more breaker spaces.

In the meantime, if you have trouble again try tightening up the connections everywhere, snap the breakers in and out of their spaces a couple of times which helps to scrape away any corrosion in the push in connection and opening and closing the breakers several times will sometimes restore conductivity since the contacts have (or should have) a wiping action against each other as they open and close. That might get you through until you can do a proper fix.

 

[k0ua]

Can someone tell me why for sure the neutral and the ground need to be seperated in a sub panel but not on the main panel? If I was guessing , I would think that seperating them makes sure that the ground does not carry any current, and therfore does not have a difference in potential on it? But I would like to hear one of you Electrical proffessional's weigh in on it.

James K0UA

 

[techman]

You should have one known point where the power neutral leg (the ground, but not earth ground) are connected together. This point is then established at a point known as the star ground. All grounds should radiate out from this point, like on a star. If you have a sub panel, you can (and likely will) have current flowing through the neutral from the sub to the main panel. Since this wire has some resistance, the current flowing will cause some voltage on that wire between the sub and main panel. If you tied the ground and neutral together at the sub, now the neutral and ground would have some voltage above ground due to any neutral current. Now grounds from the sub could be several or more volts above what should be ground. The higher the current, the more volts above ground. If you had a fault (short circuit or overload), the high fault current can move the sub's ground 10's of volts above ground. That would mean that ALL grounds connected to the sub would be above ground by that voltage, creating a hazard to anyone who might be in contact with a device or appliance that is grounded through the plug.

The goal in this is that in normal operation of things, no current ever flows through the ground wire. It is there only for protection from faults and shorts.

paul (EE)

 

[k0ua]

You should have one known point where the power neutral leg (the ground, but not earth ground) are connected together. This point is then established at a point known as the star ground. All grounds should radiate out from this point, like on a star. If you have a sub panel, you can (and likely will) have current flowing through the neutral from the sub to the main panel. Since this wire has some resistance, the current flowing will cause some voltage on that wire between the sub and main panel. If you tied the ground and neutral together at the sub, now the neutral and ground would have some voltage above ground due to any neutral current. Now grounds from the sub could be several or more volts above what should be ground. The higher the current, the more volts above ground. If you had a fault (short circuit or overload), the high fault current can move the sub's ground 10's of volts above ground. That would mean that ALL grounds connected to the sub would be above ground by that voltage, creating a hazard to anyone who might be in contact with a device or appliance that is grounded through the plug.

The goal in this is that in normal operation of things, no current ever flows through the ground wire. It is there only for protection from faults and shorts.

paul (EE)

Thank you, that Is where I was headed, in that you could have a voltage rise on the ground, because of the current that would possibly be flowing in the ground from the sub panel if it was tied in. and of course touching a grounded appliance fed from the sub panel and lets say a grounded water pipe would show a difference in potential. OK I think I have it now. thanks.

James K0UA