Why did the radiator shock me?

The pipework was carrying a voltage you could feel. A heating component, an immersion heater, a cable, the bonding or the supply are possible. Tests decide which.

Could it be the boiler?

It could. Report whether the shock happens while the heating is running. Do not remove boiler covers.

Bonding joins water, gas and heating pipes to the electrical earth so they should not sit at different voltages. It is not a guarantee that a breaker will trip before a shock, and it does not stop a broken supply earth putting voltage on those pipes.

Is a bathroom radiator worse?

Wet skin and a wet floor make the same voltage more dangerous. Keep off the rail and the taps.

Electric Shock From Radiator

A radiator or heating pipe gives a shock, even a brief one. Keep off the heating metalwork and the taps. The main switch does not make those pipes safe.

High risk

Blake FolgadoCo-founder, Tradehand

Published 1 February 2026Updated 28 September 2026

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What's happening?

Radiators and heating pipes are large metal paths. A shock from one can be the same problem as a shock from a tap: current on the pipework. Possible sources include a pump, motorised valve or boiler, an electric towel rail, an immersion heater, a cable against a pipe, missing bonding, or a fault on the supply earth. Children can touch a radiator without meaning to. The feeling does not prove the bonding is missing.

What usually causes it?

A pump, valve, boiler or electric towel rail leaking current onto the pipes
An immersion heater on pipework shared with the heating
A cable touching a heating pipe
Bonding that is loose, broken or missing
A supply fault that raises the voltage on bonded metal, including from a neighbouring home

Is it dangerous?

Yes. The same pipes can be live at every radiator, and a short contact still counts. Wet hands in a bathroom make it worse. Bonding joins pipework to the electrical earth. It does not guarantee a breaker will trip before you feel a shock, and an RCD does not operate for a broken combined earth and neutral on the supply. Call 999 if someone is unconscious or not breathing normally. If they seem well, still get a medical assessment: Electrical Safety First says injury, including a disturbed heart rhythm, may not show at once.

Can I fix it myself?

Do not touch the radiator again, and do not touch taps or other pipes to compare. Leave the radiators and taps unused. Call 105 in England, Scotland and Wales and an electrician. Switch off a towel-rail switch or the main switch only if you can reach and operate it without touching the rail, other suspect metal, or standing in water. If you are not sure, keep away. Switching off does not make the pipes safe: the IET records that voltage on bonded metal can remain after the installation is isolated. Tell them which rooms, whether your hands were wet, whether the boiler was running, and whether anyone is hurt.

When should you call an electrician?

Call 105 and an electrician before the heating metalwork or taps are used again. The electrician may need the person who services the boiler if the tests point there.

What will the electrician actually do?

Prove the relevant circuits dead where they will be opened, and test radiators and pipes for voltage, including after isolation
Check bonding without assuming it is the failed part
Test the boiler electrics, pump, valves, any electric towel rail, and the protective device
Retest after repair, and ask the network operator to check the supply when the tests point that way