Why does my washing machine give me an electric shock?

Why your washing machine gives you an electric shock

If you feel a shock when you touch the door or casing, two things are failing at once. First, there is a leak inside the appliance: a worn heating element, a chafed cable or damp in the motor lets current reach the metal. Second, the installation is not carrying that current away. In a home in good condition the leak would run down the earth wire (the green and yellow one) and the RCD, the diferencial in a Spanish fuse box, would cut the power as soon as it passed 30 mA.

The most common causes

• A socket with no earth. Common in older Spanish installations where the protective wire was never run, or a socket without the earth contact was fitted.
• An extension lead without earth, or a cut or loose earth wire in a junction box or the fuse box.
• A faulty RCD that does not trip even though there is a leak.
• A fault in the washing machine itself: heating element, motor or internal wiring with damaged insulation.

What to do now

1. Do not touch it with wet hands or bare feet.
2. Unplug it, or switch off that circuit’s breaker.
3. Press the TEST button (marked T) on the RCD. If it does not trip, it is not protecting you and the check is urgent.
4. Do not use it again until it has been checked.

What the electrician checks

• That the socket has an earth and that it really reaches the fuse box, by measuring continuity.
• The earth resistance of the building or the home.
• The RCD: that it trips at the right current and in the right time.
• The washing machine circuit, which Spanish regulations call C4 (washing machine, dishwasher and water heater), with 4 mm² cable and 20 A protection.
• The insulation of the machine, to see whether the leak is in the appliance and it needs repairing or replacing.

What it costs

A check of this kind has a guide price of 70 to 100 euros, plus whatever repair is needed. A new earthed socket on the washing machine circuit costs 40 to 120 euros, depending on the distance to the fuse box and whether the wall has to be chased.

When to call an electrician

Whenever any appliance with a metal casing gives a shock: it is an active leak and the next one may be stronger. In Seville, Spain, our 24-hour emergency electrician deals with shocks from taps and appliances, and if your home has no earthing (grounding), a full check is part of rewiring old apartments.