Why is my neutral wire showing 230V to earth even though nothing is switched on?

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A neutral wire reading 230V to earth usually means the neutral conductor has lost its connection to earth at the supply end, often called a lost neutral or open neutral fault. This is a serious and potentially dangerous condition. The most common cause is a broken or disconnected neutral at the meter tails, distribution board, or street supply. Switch off your main breaker immediately, do not use any appliances, and call a qualified electrician or your DNO if the fault is on the supply side. Do not investigate the wiring yourself. Finding 230 volts on a neutral wire is genuinely alarming, and rightly so. In a healthy electrical system, the neutral wire should sit at or very close to zero volts relative to earth. When it shows 230V, something has gone seriously wrong, and the fault can create real danger throughout your home.

What this reading most likely means is that the neutral conductor has been broken or disconnected somewhere between your property and the electricity substation. When this happens, the usual reference point that keeps neutral at zero volts is lost. Voltage then appears on the neutral in a way that should never happen under normal conditions.

Here are the most common reasons this happens:

1. A broken or corroded neutral connection at your meter box or main fuse.
2. A faulty connection inside your consumer unit or distribution board.
3. A fault on the street supply, where the DNO neutral cable has broken or corroded.
4. A wiring fault inside the property where live and neutral have been swapped at a socket, light fitting, or junction box.

What you should do right now:

1. Do not use any electrical appliances until this is investigated.
2. Switch off the main breaker at your consumer unit if you feel safe doing so.
3. Do not touch any wiring, meter equipment, or junction boxes yourself.
4. Call a qualified electrician straight away.
5. If the fault seems to be on the street side of your meter, call your District Network Operator (DNO). You can find your DNO by entering your postcode on the Energy Networks Association website. This call is free and available 24 hours a day.

A lost neutral is one of the most dangerous electrical faults a property can experience. It can cause appliances to receive over-voltage or under-voltage, potentially starting fires or destroying equipment. Please treat this as an emergency and do not delay getting professional help.