I got a dry tumbler and a washing machine that give off shocks when touched on the inner barrel.

I'm in Europe 230AC 3 phase 50Hz but no ground(old house) ground is connect to neutral at main panel going around the main HPFI breaker.

With high impedance DMM I measure 120V between each machine inner barrel and water pipe. Between them I measure 200V. All at 50Hz. Putting meter in low impedance I measure 4V between them and 2V to water pipe. Taking some cobber wire and connecting to washer and then tabbing the dryer I can throw small sparks.

If I turn off the power on the wall socket all measurements go to zero.

The machines are not grounded at the wall socket.

My first guess was capacitive coupling from the main breaker panel that is right next to the machines but I'm not so sure when all goes to zero when I turn off the power and I can throw continuous sparks when on.

Thank you for any help!

  • The purpose of grounding at the plug is to ensure that leakage current goes to ground through the wire rather than through you. Running these machines ungrounded is not safe until the problem has been isolated and fixed. Isolation will likely require temporarily disconnecting circuits until you find the one that is leaking, then disconnecting sections of that until you find where it is leaking.
    – keshlam
    Jul 19, 2016 at 1:14

1 Answer 1


You definitely have a problem, either a hot-chassis fault in the equipment (which would have been suppressed by a proper ground) or a loose neutral wire (which will cause the neutral to float). I don't know how things work in Europe, but in the US, laundry equipment is allowed to use neutral as ground, bonding neutral to chassis, when hooking a new washer to old wiring. Every few years, someone dies from a lost neutral which causes the chassis to energize at 120V. (Our neutral is pegged at the midpoint in the 240V spread, 120V on each leg).

You can dismiss capactive coupling by placing a small lamp (e.g. incandescent night light) across the points being tested. (That is to say, in parallel with the meter). It will sink capacitive/inductive float. However if the lamp actually lights, you know you've got a serious problem. In any case, capacitive coupling would not develop over such a short wire run, and cannot spark continuously like that.

I honestly doubt you would feel capacitively coupled current. If you got "kissed", it is probably a lethal current, and you were saved by the impedance of your shoes, floor etc. You can't count on that, and the threat should be treated as safety-critical. Immediately unhook the machine, validate the cord/plug connection, and if that's good and the machine still fails, bin it!

Honestly, the usual reason people don't modernize their laundey wiring is difficulty of long wire runs through walls etc. But if the service panel is right there, it's time to wire a proper, modern grounded receptacle to code, and reconfigure the appliance's wiring to use ground properly. My guess is, you do that, your problem will go away, or at least resolve itself definitively with a breaker trip.

  • Dryer not washer...and the NEMA 10 hack isn't a thing in Europe b/c they only have a single leg of service unless they're getting 3ph, but the gist of your answer's otherwise good. Jul 19, 2016 at 2:25
  • Yes, if his neutral was bonded to ground, it would be pegged to one pole of the 240, not the midpoint as we do. But I suspect his system neutral is not bonded to ground, and there's all sorts of floatin' going on. He's comparing voltages on the washer to the dryer and noting neither of them is near the potential of a water pipe, and they are nearly 240 apart. Whatever's going on, this is no time not to be grounded. Jul 19, 2016 at 4:46
  • @Harper I don't have a ground rod. We use "nulling" where the earth wire is bonded to the neutral at main panel. But why do low impedence mode only measure 4volts? And if I was actually able to pull any current(I can't measure any) from dryer and send it to ground through the pipe my HPFI should brake at detecting 30mA not being returned by the neutral wire. I'll try and measure the outlets when I get home. It seems there is a lot of potential but that it collaps under load with very little current.
    – CodeMonkey
    Jul 19, 2016 at 5:32
  • Ok I've checked the Wall outlet and all is fine. Talked to a friend who said it was simply because it wasn't grounded. This causes its ground to float. Apparently some electronic capacitors are often connected to ground to filter out noise therefor requiring the machine to be grounded since it by design has a tiny leakage current but enough to raise the potential when ungrounded and give a small shock. Tomorrow I'll get an adapter and check the earth in the wall and ground it properly.
    – CodeMonkey
    Jul 19, 2016 at 23:22

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