Black Residue around Oulets?

I inspected a condo this morning and about one third of the outlets had a black residue around them. I think when devices are plugged into the outlets there must be some arching?? What can be the cause of the residue and what’s the fix? Thanks in advance for the answer. :smiley:


Hi Skip,

Outlets like anything else don’t improve with age, I suspect that the outlets are rather worn and don’t grip well on the plug tangs, well used outlets over 20 years or so old tend to need replacement.



Thanks for the input Gerry. This unit is nine years old. Could it also be poor workmanship and/or low quality outlets?

My answer to this would be no. If it were the why doesn’t every house have this.

This may sound silly but do they burn a lot of candles in this house?
How about air infiltration around the boxes/devices?

I would guess it is NOT arcing.

Looks like dirt to me too. I don’t think it’s arcing. . .

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Hi Jeff, I believe you are correct, on second thoughts I bet it is a ghosting type problem due to a relative lack of inslulation behind the outlets on exterior walls.

Skip, was this issue more apparent on the exterior walls?



I saw the residue on interior and exterior wall outlets. Dirt around here is red. As in rock hard clay. It’s not dirt. The palce was vacant. Can’t tell if they burned candles. The residue is only around outlets. No residue on switch plates. And no residue on an receptale unless its around the outlet.

I should have sniffed the outlets. To see if they smelled like an electrical issue!! :mrgreen:

Sometimes this is observed when electrical outlets are non-compliantly installed in stud bays that are being used for return air. A tiny bit of return air is being sucked through whatever switches and/or receptacles are installed in that stud bay. A home with negative pressure issued, due to a number of factors (including tight construction, in which exhaust fans are used in the kitchens and bath, or combustion air is taken from indoors, or an improperly function air to air heat exchanger), will observe a tiny amount of air infiltration through the devices mounted in the exterior walls, dragging in whatever pollution along the way.

I see this very commonly, and I wouldn’t especially call it alarming from my point of view, unless the device fails to function.

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That stripe on the plate is a little puzzling. Did you do that when you swiped it with your finger, or was that there? Seeing that stripe, I’m starting to think “Glade Plug-In” or something along those lines. We have a couple around the house, and they seem to attract dust, for some reason.

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Plug-in air freshener or nightlight

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Exactly…I found this around every receptacle that had one of these. The lady was trying to hide cat smell, many cats’ smell.

That’s where I swiped my finger. The residue was on outlets no where close to stud bays with returns. I saw this once a couple of months ago in another property. It was only on one outlet.

Now that I think of it, I could tell these people didn’t clean much. The place was not kept well. Maybe it is dust that formed around plug-in air fresheners. I would hate to miss a major electrical issue on this one. I might call for an electricain anyway. Any thoughts?

Those plug in air fresheners produce more than enough heat to create warm air currents. This is your culprit.

I have many thoughts, but none of them apply to this situation at the moment. Right now, my thoughts are more along the lines of how good a chicken patty sandwich sounds.

I want “wall wart” in the office pool. The dirty spot is below the receptacle. A Glade would have a sweep up.

I just had a realtor call and ask about something similar.

Haven’t been there yet to inspect but I’ll know more on monday.

Skip, I think you’re onto the cause in observing the people weren’t that clean. I’d have looked at the wall switches, and if they had the same greasy smears, I’d assume it was greasy fingers and not arc burns, which in the latter case would originate at the receptacle slots.

Chinese drywall?