Bus bar discoloration

I had an unusual color an a bus bar today.

I am recommending evaluation. Anyone have an idea why the bus bar looks scorched? Besides the obvious possibility over heating.

Hard to tell, picture is pretty blurry. The bottom left breakers are tripped though.

What exactly are you recommending further evaluation for? Where are your circuit ground conductors?

I’ve seen this discussed before and the general feeling is a bit of “rainbowing” discoloration is normal/common. From what I can see there that looks pretty bad on the one side and I’d likely call it out too.


That was going to be my next question. This is a small condo and there were armored cables being used. I assumed that would explain the missing grounding conductors. But yes it took me back when i first saw it.

To me it looks like something caused an overheating issue on the left side busbar. What caused it and the extent of the damage not sure, that’s where the further evaluation from a qualified electrical contractor comes in. A thermal imaging device could have been helpful. I would just comment with something like this.

“At time of the inspection this inspector observed some excessive discoloration on the left side busbar within the electrical distribution panel. This condition typically indicates possible overheating, corrosion or some other problem not visible. Recommend further evaluation from a qualified electrical contractor and any corrective repair that may be necessary.”


Since the branch circuit wiring method was AC cable the jacket of the cable is the equipment grounding conductor. That is code compliant.