Panel bussing discolored, ground conductors, neutrals discolored

[theavidcitizen]

As you can see, this subpanel received what I believe to be some serious heat, but I've never seen it before, so I'm wondering what the cause could be. First instinct is an overcurrent event. Anyone have input on this?

Also, the customer is wondering if the branch circuit wiring is still viable beyond the panel. No damage to devices at the ends, that we have found, lighting works and has no visible damages. I am inclined to say the wiring needs to be remediated with the panel.

 

[jim dungar]

Those bars look like corrosion of the tin plating. Heat would lkely have affected the entire bussing and main lugs.

My old house had a panel with one phase discolored and the other nothing. The space under each breaker looked normal.

 

[Eddie702]

As far as the wiring goes you cut and strip it and see what it looks like. If it was overheated, you usually have problems stripping it and can't get the insulation off.

 

[infinity]

The copper looks like it been subject to a corrosive material in the air similar to what we've seen from off gassing of Chinese drywall.

 

[theavidcitizen]

Those bars look like corrosion of the tin plating. Heat would lkely have affected the entire bussing and main lugs.

My old house had a panel with one phase discolored and the other nothing. The space under each breaker looked normal.

Yeah, that's what's throwing me off, there's just no other indications of any abnormal power event. The main panel is an older split bus panel, but it's in pretty good shape. This subpanel feeds a shop, then another subpanel in a garden shed. The electrical in the main house is solid, grounding and bonding is solid and complete. I just dont know

 

[theavidcitizen]

As far as the wiring goes you cut and strip it and see what it looks like. If it was overheated, you usually have problems stripping it and can't get the insulation off.

The wiring downstream of the breaker looks fine from the outside, its mostly exposed in an uncovered shop. End of line devices look good, test ok.

 

[ATSman]

Yeah, that's what's throwing me off, there's just no other indications of any abnormal power event. The main panel is an older split bus panel, but it's in pretty good shape. This subpanel feeds a shop, then another subpanel in a garden shed. The electrical in the main house is solid, grounding and bonding is solid and complete. I just dont know

I doubt that the blue color is caused by overheating since the lugs, as others mentioned, show no evidence of this. If I recall the blue coating at one time was added by the manufacturer to prevent corrosion of the silver/tin busbars.