Glossary
Neutral wire (neutro, neutral conductor)
The blue return conductor for the current, which on low voltage networks is connected to earth at the distributor transformer. Together with the live it closes the circuit of every single-phase appliance.
What the neutro is
The neutro is the blue wire the current returns on after passing through an appliance. On the distributor’s network the neutral is connected to earth at the transformer substation, so under normal conditions its voltage to earth is very low.
Neutral and earth are not the same
Both sit close to zero volts, but they do different jobs:
- The neutral carries current whenever an appliance is on.
- The protective earth (ground) only carries current if there is a fault, diverting it so the RCD trips.
Joining them inside a home is a serious mistake: the RCD would stop working properly.
A broken neutral
This is one of the most dangerous faults. If the neutral breaks in the service cable or in a building’s communal installation, the voltages become unbalanced and some flats (apartments) can receive far more than 230 V. Appliances, televisions and boilers can burn out within minutes. That is why a permanent overvoltage protector cuts the supply when the voltage stays high.
Signs of a faulty neutral
- Lights that brighten and dim when another appliance switches on.
- Bulbs that blow frequently.
- Several appliances failing at the same time.
Neutral on three-phase supplies
On a balanced three-phase installation the neutral carries little current. With lots of electronic equipment, harmonics add up on the neutral and can heat it, something to watch in offices and shops. See surge protection in Seville, Spain.
Related services
Flickering lights
Lights flickering in your apartment, or dipping every time something switches on, are not a minor detail: they usually warn of a loose contact, a faulty neutral or a voltage drop in a cable that has become too small. An electrician in Seville, Spain measures, finds the source and repairs it before it turns into a bigger fault.
Surge protection
Surge protection in your fuse board in Seville, Spain is the cheapest way to save the fridge, TV, router, boiler and induction hob from lightning, storms and voltage surges. We fit protectors against transient and permanent overvoltage, or combined units, in homes, business premises, EV chargers and solar installations.
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.
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.