Neutral/Earthing· System Faults· Reviewed July 2026

What is a PME failure and what should I do immediately?

Quick answer

A PME (Protective Multiple Earthing) failure occurs when the neutral conductor from the electricity distributor becomes open-circuit, causing exposed metalwork in your home to rise to a dangerous voltage. The most common cause is a broken or disconnected DNO neutral cable. Immediately switch off your main incomer, do not touch any metalwork or appliances, and call your electricity distributor (e.g. National Grid, Western Power) on their emergency line. Do not attempt any investigation yourself — this is a life-threatening network fault.

🏠Homeowner view
What is a PME Failure and What Should I Do? PME stands for Protective Multiple Earthing, which is the most common earthing system used in UK homes. Under normal conditions, the electricity distributor's neutral cable also serves as your home's earth. This means metal parts of your appliances and wiring are kept safely at earth potential (0 volts). A PME failure happens when that shared neutral wire breaks or becomes disconnected, either at the street, at the service head, or along the distributor's underground or overhead network. When this happens, exposed metalwork throughout your home — radiators, taps, appliance casings, light fittings — can rise to a dangerous live voltage, sometimes over 100 volts. This is extremely serious and has caused fatalities. Warning Signs You Might Notice Lights flickering or glowing dimly even when switched off Appliances behaving strangely or failing A mild tingle or shock from taps, radiators, or appliances RCDs tripping for no obvious reason Neighbours also losing power or experiencing similar issues What You Should Do RIGHT NOW Do not touch any metal surfaces — taps, radiators, cooker casings, or anything bonded to the earth system Switch off your main consumer unit (fuse box) at the main incomer switch if it is safe to reach without touching metalwork Do not use electrical appliances — unplug nothing if you have to touch metal to do it Evacuate the property if you or anyone else has felt a shock Call your electricity distributor's emergency line immediately — this number is on your electricity bill, or dial 105 (the national power cut number) Do not call a private electrician first — this is the distributor's network and only they can fix the fault safely When is it Safe to Return? Only re-enter and use the property once a DNO (Distribution Network Operator) engineer has attended, confirmed the neutral is restored, and declared the supply safe. Your own electrician may then need to test and verify your installation before full use resumes. Remember: A PME failure is a network emergency, not a household wiring fault. Never ignore tingling from metalwork — it could save your life.

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