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!
Best Answer
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.