Short circuit repair in Seville, Spain: we find the fault and fix it

What a short circuit is and why the power goes off

A short circuit happens when the live wire comes into direct contact with the neutral or another phase without passing through any appliance that limits the current. At that instant the current rises to very high values and the circuit breaker (MCB, called magnetotérmico or PIA in Spain) cuts out through its magnetic trip, almost always with a bang and sometimes with a visible flash.

The breaker tripping is a good sign: the protection has done its job. What has to be found is where the contact happened, because while it is still there the circuit cannot work and, if the fault is intermittent, it can cause arcing and heat inside a box or behind furniture.

Short circuit, overload or leakage: they are not the same

It is easy to mix up faults that all end in “the power went off”, but each has a different cause:

• Short circuit. The circuit breaker trips instantly, often with a flash. That is what this page is about.
• Overload. The circuit breaker trips after a while, when you have several powerful appliances on the same circuit. We explain it on MCB keeps tripping.
• Earth leakage. The RCD (diferencial, GFCI in the US) trips, not the breaker. It is usually caused by damp or a faulty appliance: see RCD keeps tripping.
• Exceeding your contracted power. Nothing in the fuse board moves and the smart meter cuts the whole home for a few seconds: see power limiter tripping.
• Damage to the fuse board. If what smells or heats up is the board itself, see fuse board fault.

Where the short circuit usually is

• In a socket or a switch. Loose terminals, old switches or cables that have worked loose with use. The most common case when the flash comes from one particular socket. See also sockets not working.
• In a junction box. In older installations it is common to find joints made with insulating tape that dries out over the years and leaves the copper exposed.
• In a light fitting. Ceiling lights hung without the connections properly covered, burnt lamp holders or outdoor spotlights where water has got in.
• In a damaged cable. A nail for a picture, a drill that has hit the conduit or a poorly protected chase during building work.
• In an appliance. A worn power strip (extension lead), a charger, an iron or an appliance with a stripped power cable.

If the breaker only trips when you plug in a particular appliance, the short circuit is in that appliance and not in your installation. If it trips with nothing connected, it is in the wiring or a switch.

How we find and repair the short circuit

1. We isolate the affected circuit at the fuse board and check that the rest of the home works normally.
2. We disconnect everything on that circuit (appliances, lamps, power strips) to separate an installation fault from an appliance fault.
3. We measure the insulation between conductors section by section until we find the point of contact, opening junction boxes and switches.
4. We repair it by replacing the socket, the joint or the damaged length of cable, with the cross-section the circuit needs.
5. We check the protections. We confirm that the breaker is right for that cable and cuts out as it should, in line with ITC-BT-22 of the Spanish Low Voltage Electrotechnical Regulation, which covers overcurrent protection, and ITC-BT-19 on indoor installations.

If the damaged point has left heat marks on the cable or the wall, we show you and explain whether the rest of the circuit should be checked.

Short circuits in Seville homes

In the 1960s and 1970s flats of Triana, the city centre or La Macarena, many installations still have old joints and junction boxes that have collected dust and damp for decades. A very common case: a new ceiling light is hung in the living room, one of the ceiling cables has cracked insulation and, when the ceiling rose is closed, it rubs against the other one. The flash comes when the light is switched on. In new homes, such as those in Sevilla Este or Entrenúcleos, the short circuit usually comes from a connection made in a hurry during the move or from a faulty appliance, and it is sorted out quickly.

If short circuits keep happening at different points in an old home, it is not bad luck: it is the general condition of the wiring, and it is worth a full electrical inspection before carrying on with patch repairs.

Guide prices

We confirm the exact amount before repairing, and if the fault is in an appliance we tell you so you can decide whether it is worth fixing.

What to do while you wait for the electrician

1. Leave the breaker that tripped down and do not push it up again.
2. Unplug everything in that area of the home.
3. If you notice a burning smell, smoke or heat in a wall, also switch off the main switch and read burning smell.
4. Call us and tell us what happened: we give you an estimated time when you call and guide you to leave the home safe.

We deal with short circuits at any hour as part of our 24-hour emergency electrician service. You can see the other faults we handle on the emergency electrician page.