Glossary
Transient overvoltage (sobretensión transitoria, power surge)
A very high voltage spike lasting microseconds, caused by nearby lightning or by switching on the electricity network. It can destroy the electronics in appliances, routers, TVs and chargers in an instant.
What a transient overvoltage is
The voltage in a Spanish home is 230 V. A transient overvoltage is a sudden rise far above that value lasting only millionths of a second. It is so brief that the RCD and MCBs do not react, but it is enough to puncture the insulation of electronic components.
Where it comes from
- Lightning. It does not have to strike your building: a hit on the network or nearby induces the spike in the cables.
- Network switching. Connections and disconnections by the distributor or by large machines nearby.
How it differs from a permanent overvoltage
The transient is a very high, very short peak. A permanent overvoltage is a more moderate rise that lasts, almost always caused by a broken neutral. Each needs different protection: the transient is diverted to earth and the permanent one is cut off.
How to protect your home
The answer is a transient surge protector (SPD) in the main board, connected to a sound earth. ITC-BT-23 regulates this protection and ITC-BT-52 requires it on EV charging points. Surge-protected power strips help for a single appliance but do not replace the protector in the board.
When to call an electrician
If several appliances, the router or the boiler burn out at once after a storm, have the installation checked, the earthing tested and any damaged protectors replaced. See surge protection and storm damage in Seville, Spain.
Related services
Storm damage
If a storm or a power surge has left your home without electricity, burnt out the router or the appliances, or the RCD will no longer reset, a storm damage electrician checks the installation in Seville, Spain, replaces the damaged protections, tests the appliances and gives you a report for your home insurance claim.
Fuse board replacement
A consumer unit replacement in Seville, Spain is the upgrade that adds the most safety without building work: main switch, several RCDs, one breaker per circuit and surge protection. We replace your old fuse box, or a board with a single RCD, with a new fuse board (breaker panel) sized for your power and your circuits.
Need an electrician in Seville, Spain?
Call us or send a WhatsApp message with a photo of the job. You get a fixed quote before any work starts.