Electric shocks from taps and appliances: earthing check in Seville, Spain

Why a tap or an appliance gives you a shock

In a correct installation, every metal part that could become live by accident (the casing of the washing machine, the water heater, the oven or the bathroom pipes) is connected to the earth by the yellow and green wire. If an internal cable touches the casing, the current takes that path, the RCD detects the leakage and cuts the power.

When you feel electric shocks from taps or appliances, one of those two things is failing: there is a leakage in an appliance or a cable, and the earth is not carrying it where it should. The current then looks for another path to earth, and that path is you.

That is what sets shocks apart from other faults: here the risk is directly to people, especially in bathrooms and kitchens, where skin is wet and contact with water and the floor is greater.

Shocks, a tripping RCD or a dead socket?

These three symptoms are related but they are not the same. A shock means a leakage that nothing is stopping. An RCD (diferencial, GFCI in the US) that trips and will not stay up means a leakage that the protection is detecting, which is a good sign: see RCD keeps tripping. And sockets with no power are a different fault altogether, covered in sockets not working. If you get a shock and the RCD has not tripped, treat it as the most urgent of the three.

Most frequent causes

• A home with no earthing. Very common in older flats. The sockets have the side clips, but there is no earth behind them.
• A broken or loose earth. The protective conductor has come loose in a box or in the fuse board, or was cut during a renovation.
• An electric water heater with a damaged element. A typical cause of shocks in the shower and the bathroom tap, because the water heater (termo) is connected directly to the water pipes.
• An appliance with a leakage. A washing machine, dishwasher, fridge or oven with internal damp or a worn component.
• Broken bathroom equipotential bonding. The pipes and metal parts of the bathroom must be joined together so there are no voltage differences between them. If that bond is missing, voltage can appear between the tap and the drain.
• An RCD that does not act. If the leakage exists and the RCD does not trip, it may be faulty.

What to do right now

1. Do not touch the tap or the appliance that gave you the shock again.
2. Unplug the suspect appliance or, if you do not know which it is, switch off its circuit breaker in the fuse board.
3. If the shock is in the shower, switch off the water heater at its breaker and do not shower until it has been checked.
4. Press the RCD test button (marked with a T). If it does not trip, call us: your protection is not working.

How we check it

1. We measure the voltage on the tap, the pipes and the casings to confirm the problem and its size.
2. We check the continuity of the protective conductors from every socket and appliance back to the fuse board.
3. We measure the earthing of the building or the home to know whether it exists and whether its value is adequate.
4. We measure the insulation of the suspect appliances, starting with the water heater and the washing machine.
5. We test the RCD with a tester that measures its trip time and trip current.
6. We repair: we reconnect the earth, redo the equipotential bonding, isolate the leaking appliance or install new earthing.

The regulations that apply are ITC-BT-18 (earthing installations), ITC-BT-24 (protection against direct and indirect contact) and ITC-BT-27 (rooms containing a bath or shower).

Flats without earthing in Seville

In the 1960s and 1970s blocks of Los Remedios, Nervión or La Macarena, many homes were built without earthing or with an earth that never reached the sockets. The typical case: an old electric water heater, its element starting to fail, in a flat with no earth. The leakage trips nothing, and the first warning is a tingle when you turn off the shower tap. In these cases we replace or repair the water heater, but the real solution is to install earthing and connect the sockets and appliances to it. If the installation also has old cables and few circuits, it makes sense to consider rewiring the apartment. A full electrical inspection tells you where you stand.

Guide prices

These are guide prices. If the fault is in an appliance, we tell you so you can decide whether to repair or replace it, and if you need a new line for a kitchen or air conditioning appliance, see air conditioning and appliances. If you get a shock, call us at any hour through our 24-hour emergency electrician service.