We moved into a house a couple of years ago and found that one of the sockets, at the back of the house, simply didn't work. It wasn't too much of a problem as I ran a power supply from a nearby socket into the room and ran the washing machine from this.

I've revisted this socket as I want to put both my washer and drier in the same room.

After examining the socket using a mains tester, I found that the live supply was exactly that - live; the screwdriver lit up as expected. I tested further by plugging my drill charger unit into the socket, but this did not work (though it did work fine in another socket). Strangely, however, when testing the neutral wire inside the socket, the mains tester lit up as it should do, proving that there was a circuit being formed with the device. The socket is clean; there's no apparent damage to it, and it does not trip the consumer unit.

The socket, as stated, is located to the back of the house and is spurred from a live socket in the kitchen. At the time of examination, it did not have an earth cable from the switch to the casing, but that's probably not necessary as the earthing cable from the spur was already in place (belt and braces).

Is this a sign of a faulty switch or poor wiring involved in the spur?

  • Have you tested both outlets in the double socket? Maybe the jumper links have been removed and you're testing a live outlet and plugging into a dead one... Stranger things have happened...
    – JACK
    Commented Jul 27, 2019 at 19:29
  • Never seen a UK double socket with removable jumper links (I usually purchase the MK brand..), but the switches may have failed especially if the previous owner overloaded the socket...
    – Solar Mike
    Commented Jul 27, 2019 at 19:34
  • @lamengineer - yes, I tested both sockets with the same results. As Solar Mike said - there are no jumper links in UK sockets.
    – Paul
    Commented Jul 28, 2019 at 12:17
  • @solarmike - I had considered this, and tested the circuit 'in a fashion'. I think it's more like Owain says, below, I need to check the points between the kitchen and back room.
    – Paul
    Commented Jul 28, 2019 at 12:43
  • @Paul you say you tested the neutral and it lit up as it should do... which makes me still suspect the socket...
    – Solar Mike
    Commented Jul 28, 2019 at 12:58

2 Answers 2


Mains tester screwdrivers are useless, dangerous and should be thrown away. They rely on current passing through a neon, resistor and your body and if they are faulty or they get wet they can kill you. They give false positives and negatives.

Check that all wires are done up tightly in the socket and that the terminal screw isn't gripping the plastic insulation on the wire. And check at the kitchen socket it's spurred from too. It's possible the neutral is out, but the live is connected, or vice versa.

  • Thanks Owain - I'll check those things and get back to you. Oh, and I'll definitely get rid of the mains tester.
    – Paul
    Commented Jul 28, 2019 at 12:13

Strangely, however, when testing the neutral wire inside the socket, the mains tester lit up as it should do

A neon screwdriver or volt stick should not light up when touching the neutral.

If it does then it is likely an indication of a bad neutral connection, which leads to the neutral becoming live via the load.

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