Earthing installation and upgrades for homes in Seville, Spain

What earthing is for

Earthing is the connection between your installation and the ground. Every metal part that could become live through a fault (the casing of the washing machine, the oven, the water heater, the earth clips of the sockets) is connected to it by the yellow and green cable. If an internal cable touches the casing of an appliance, the current goes to earth instead of through your body, the RCD detects that leakage and cuts the power.

Without earthing, that same leakage stays on the casing waiting for someone to touch it. The RCD will only trip once the current passes through the person. That is why we say that without earthing the RCD cannot protect you properly.

Signs that your home has no earthing, or poor earthing

• Shocks when you touch the tap, the shower, the washing machine or the fridge. If it is happening now, read electric shocks from taps.
• Sockets without the side earth clips, or with them but no cable connected behind.
• No yellow and green cable reaches the fuse board.
• The RCD never trips, not even when an appliance is clearly faulty.
• An installation 30 or 40 years old that has never been renovated.

How we install or improve the earthing

1. We check what is there. We confirm whether the building has an earth network, what condition it is in and whether it reaches your home.
2. We design the solution. In a house with its own land, earth rods or a buried conductor; in a flat, connection to the building’s earth or creation of a new one in a common area.
3. We install the electrode (earth rod or buried conductor) and the main earth line up to the fuse board.
4. We connect every circuit: sockets, fixed appliances, bathroom and kitchen, including the equipotential bonding of the metal parts of the bathroom.
5. We measure the earth resistance with an earth tester. The lower the value the better; it must be compatible with the sensitivity of the RCD, as ITC-BT-18 requires.
6. We test the RCD to confirm that it now does detect and cut a leakage. See also RCD keeps tripping if it starts tripping once the earth is connected, which can reveal leakages that were hidden before.

The rules that apply are ITC-BT-18 (earthing installations) and ITC-BT-26 (specific requirements for indoor home installations), together with the UNE 20460 standard.

In flats: the building’s earth

In a block of flats the earthing is usually shared: an electrode in the foundations or the building’s ground and a line that runs up the stairwell to each home. In older buildings there are three possible situations:

• The building has earthing, but it does not reach your home. The simplest: the protective conductor is run to your fuse board and connected to the circuits.
• The building has earthing, but in poor condition. It has to be measured and, if the value is not adequate, improved with new electrodes.
• The building has no earthing. It has to be created, usually in a courtyard, a basement or an inspection pit in a common area, in coordination with the comunidad.

Flats without earthing in Los Remedios and other Seville neighbourhoods

In the 1960s and 1970s blocks of Los Remedios, Nervión or La Macarena it is very common to find homes with no earthing or with three-pin sockets that were never connected to anything. The typical case is an owner who changes the kitchen, installs a dishwasher and an induction hob and discovers, on measuring, that the flat has no earth. If the building has an earth network on the ground floor or in the basement that never reached the homes, the solution is to run the line to the fuse board; if not, it has to be raised with the comunidad. When the wiring is also old, the sensible thing is to take the opportunity to rewire the apartment.

In villas and houses in the Aljarafe or Camas with their own land, the earthing is solved within the plot, and the measurement depends a great deal on the type of soil. More on the area on Aljarafe north.

Guide prices

As there is no established public price, these are estimates that we adjust after seeing the building and the access. If you want to know the overall condition of your installation, earthing included, ask for an electrical inspection. More work on the electrical installations page.