discolored neutral bus screws


  #1  
Old 09-29-14, 06:10 AM
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discolored neutral bus screws

I tried to show in the photo below where I have about 4 screws (red lines point to them) on my neutral bus that have a whitish residue on the tops of the screwheads. They are not as shiny as the other screws. Kind of reminds of me of the metal loosing it shiny plateing.

I assume this is caused by moisture/humidity which I have hopefully addressed by sealing the conduit into the panel.

The discolorization is not on the bus itself and its not on the threads of the screws or on the wires themselves... just the screw heads. Also 2 of the 4 screws that exhibit this discolorization, do not have wires terminated in them.

Is this something I should be concerned about?

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  #2  
Old 09-29-14, 07:42 AM
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I would not be concerned. You can wipe on PB Blaster anti corrosion spray (don't spray it on) on the heads. I would be more concerned with the hot wires not being captured properly under the attachment points of the breaker. Seems they are outside the holding clamp. Could be the picture, though.

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Last edited by ray2047; 09-29-14 at 07:52 AM. Reason: Add caution.
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Old 09-29-14, 08:13 AM
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I'd also be concerned about why a white wire, apparently a neutral conductor, is taped green designating it to be a EGC (ground wire).
 
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Old 09-29-14, 09:04 AM
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Ungrounded conductors are firmly and properly placed under the breaker plates... the photo makes it look strange. And indeed the white wire was redesignated as EGC for a dryer circuit, I suppose electricians didn't have any green wire. It also passed inspection like this although I wasn't particularly happy they didn't just use green wire.... but we digress.

Thanks for your opinion Chandler but wiping PB blaster on it is not something I want to do. If I were going to use some sort of anti-ox compound I would use noalox something designed for electrical use....

Other than that unrelated stuff.... do you think this is something I should address by replacing the screws, the entire bus or something? Is that abnormal that that discolorization has occurred in as little as 6 months?
 
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Old 09-29-14, 09:22 AM
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If it's not on the threads or at the connection points of the wire to the bus, I don't think I'd really worry about it. if you want, you could use some anti-ox and a trimmed down (stiffer) acid brush to apply it.

As Joe brought up though, a ground should not be connected to the neutral bar. I'd be more concerned about that. I can't understand how that passed?
 
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Old 09-29-14, 09:33 AM
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As Joe brought up though, a ground should not be connected to the neutral bar. I'd be more concerned about that. I can't understand how that passed?
This is a main panel. EGC can be on same busbar.
 
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Old 09-29-14, 09:47 AM
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Oh duh....I was thinking of a sub I guess.
 
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Old 09-29-14, 12:01 PM
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Then problem with the white wire remarked green is a wire #6 or smaller can't be remarked as a ground. The second question is if he has cable how could a white been used as a ground.
 
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Old 09-29-14, 01:03 PM
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The second question is if he has cable how could a white been used as a ground.
conduit. individual conductors.

So should I sweat this ?? (ie the discoloration on the screws as I pointed out).
 
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Old 09-29-14, 01:09 PM
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Well, you got a couple of answers to the original post.

It's the nature of the beast, show a picture of a panel/deck/wood working project and people will comment on everything they see...lol.
 
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Old 09-29-14, 01:23 PM
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I would not worry about those screws.
 
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Old 09-29-14, 01:54 PM
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I would not worry about those screws.
Thanks.... you do see what I am saying though? The top screws are nice and shiny and the ones with the red lines pointing to them has that whitish residue type discoloration.

I should mention the equipment is only 6 months old.

For that first 6 months the entrance conduit was not sealed very well. In order to alleviate what I think happened due to condensation?? I sealed the hole with duct seal.

Let me put it a different way, does that discoloration happen due to overheating? And if so, I mention 2 of the 4 holes don't have a wire under the screw...?

Thanks for the bandwith though... being that its so new I just wanted some piece of mind that its not something to concern myself with.
 
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Old 09-29-14, 04:04 PM
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If it is only 6 months old ask the original installer back to examine and correct any problem.
 
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Old 09-29-14, 05:08 PM
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Obviously its pretty minimal, so I have hesitated calling back thinking they would just seal the conduit entering the panel with duct seal as I have already done and call it good. The only thing I couldn't do however is replace a bus bar.... but Im not sure they would go as far as that and I really don't want to loosen up the factory bar and have a replacement in there if its not necessary.


So I guess some remaining questions (if your not tired of this thread already)....

Does discoloration as shown there result from a high resistance connection on that bar or an overload of the service neutral in general?

Do you think unconditioned air coming into the panel thru the conduit would cause this?

Since I plugged the conduit with ductseal, do you think its safe to call it good and trust no more unconditioned air is filtering thru that pipe?
 
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Old 09-29-14, 05:16 PM
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The problem with your questions is you are asking us to foresee the future. We can't. We can only give opinion. Cleaning it up and seeing if it reoccurs in a short time would be a way to see if there might be a problem.
 
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Old 09-30-14, 04:35 AM
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The problem with your questions is you are asking us to foresee the future. We can't. We can only give opinion.
I understand that Ray... so how about an opinion on those questions?

Most importantly, does that look like the result of a loose connection?

edit:

I added ductseal to the conduit entering the panel. Is it standard to have the conduit sealed there or inside the meter can or both?

Thank you.
 

Last edited by cws05; 09-30-14 at 05:41 AM.
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Old 09-30-14, 07:07 AM
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And indeed the white wire was redesignated as EGC for a dryer circuit, I suppose electricians didn't have any green wire. It also passed inspection like this although I wasn't particularly happy they didn't just use green wire
So.....there are two white wires coming from the conduit for the dryer circuit?
 
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Old 09-30-14, 07:15 AM
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To belabor the unrelated point are there any other green wires. With a metal conduit system there usually are no ground wire because the metal conduit is the ground so why did they need a ground wire?
 
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Old 09-30-14, 07:46 AM
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To belabor the unrelated point are there any other green wires. With a metal conduit system there usually are no ground wire because the metal conduit is the ground so why did they need a ground wire?
Its a 4 wire dryer circuit obviously, we all know you can just jumper the box but a redundant egc is installed. And I agree, your belaboring an unrelated point. Thanks.
 
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Old 10-01-14, 06:53 AM
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And I agree, your belaboring an unrelated point.
So sorry you feel that way. We were just pointing out an obvious code violation.
 
 

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