I replaced a single socket with a double today in a new build house we've lived in for around a year. Upon disconnecting the live wire I noticed it was blackened and looks to have caused some arc damage to the plastic moulding of the single socket I was replacing.

I re-terminated the wire and fitted the new socket, but is the charring something I should be worried about? Knowing the build quality issues in this house I'm less than confident of a lot of things.

The socket is in a utility room, but there have been no leaks in that area as far as I'm aware. Could it just have been caused by a poor connection by whoever fitted it?

Damaged live wire

  • 4
    Including a picture of the back of the original socket may help determine just how bad things may have been.
    – FreeMan
    Commented Oct 6, 2022 at 11:59
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    If you decide to fix it yourself, remember to sand off the wire to remove the charring, or if there's enough slack, snip off the char. That charred surface is not great for conductivity and it will happen again.
    – Nelson
    Commented Oct 7, 2022 at 3:53
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    You might want to watch out for other problems related to non-compliant/shoddy workmanship. Dunno if it's legal where you are, but wire colours look European, yet in all European countries I'm familiar with it would be very much not okay to just stuff a socket into a hole in what looks like particle board with no box to be seen. Any overheating/arcing could easily set the board on fire.
    – TooTea
    Commented Oct 7, 2022 at 8:12

2 Answers 2


A poor/loose connection is a good guess.

In North America most connections now are required to be done to specific torque values to reduce the chance of loose connections. Unknown if the same is required elsewhere. Device torque values are usually found in the instructions and/or the device.

If one connection was found in a newer house, would check all the other connections. That might be the only one, but fires not something to fool around with. Double check power is off on any circuit that is being check for loose connections.

Edit I would not try to find North American torque values to use with European devices. The design specs of European devices could be too different for a straight transfer.

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    Mostly similar in Europe, although many electricians can only be bothered to torque aluminium properly while for copper they use "real tight" as the only standard.
    – TooTea
    Commented Oct 7, 2022 at 8:20
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    Indeed, a loose connection to a socket in my kitchen fried not only the wire but the socket as well. "Real tight" wasn't tight enough.
    – rghome
    Commented Oct 7, 2022 at 9:13
  • I can't comment on the rest of Europe, but here in the UK switchgear tends to come with torque specs but wiring accessories don't. Commented Oct 7, 2022 at 16:35

You mentioned your concern of the build quality and yes that condition on the wire could be the result of not being fastened securely. (an unfortunate result of hurried workers) That is the most likely reason, however I would check the amp draw on that circuit just to be sure.

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