What is electric shock?

Glossary · Wiring, circuits and faults

How electric shock works

A shock happens when your body completes a path for electricity. The current flows through you instead of staying in the wiring or the appliance. In a home that usually means contact with a live part: a faulty appliance, a damaged or frayed cable, or a fault in the fixed wiring.

Electrical Safety First lists danger signs worth acting on before anyone is hurt. They include sparks or smoke from a plug or appliance, scorch marks around a socket, damaged or frayed cables and melted plastic.^{[2]Electrical Safety First, Extension leads, cable reels and block adaptors} If you notice burn marks on plugs and sockets, buzzing or crackling sounds, or fuses and circuit breakers tripping, the charity says to get a registered electrician to check your electrics as soon as possible.^{[3]Electrical Safety First, FAQ for Electrical Safety - Your Questions Answered}

What to do if someone is being shocked

Electrical Safety First gives these steps for anyone who believes a person has had, or is getting, an electric shock.^{[1]Electrical Safety First, Electrical Safety First Aid}

The last row matters. The charity warns that the effects of a shock may not be immediately obvious. It can cause internal injuries such as deep burns, muscle damage, heart rhythm disturbances or broken bones caused by muscle contractions.^{[1]Electrical Safety First, Electrical Safety First Aid}

How an RCD helps

An RCD (residual current device) sits in the consumer unit. It is described by Electrical Safety First as a device that protects you from electric shocks if a product is faulty. It limits the time that current can flow through the body if a person touches a live source, although it is not a guarantee of absolute safety.^{[1]Electrical Safety First, Electrical Safety First Aid} If your home has no RCD protection, the charity says an RCD plug can be used on the socket where a product is plugged in.^{[2]Electrical Safety First, Extension leads, cable reels and block adaptors}

You can check an RCD with the test button on the device. If pressing it does nothing, a registered electrician should investigate.^{[3]Electrical Safety First, FAQ for Electrical Safety - Your Questions Answered} Our page on the RCD trip test covers what the test does. If an RCD keeps tripping, there is likely to be a fault with an appliance or the wiring that needs investigating, so see why does my RCD keep tripping.^{[3]Electrical Safety First, FAQ for Electrical Safety - Your Questions Answered}

Finding and fixing the cause of a shock is work for a registered electrician. It is not a job to try yourself. Our emergency electrician page explains what we can attend.

Example

Priya is drying her hair in a Headingley flat when the hair dryer’s cable shows a bare section and she feels a sharp tingle in her hand. She pulls the plug from the wall, which cuts the supply, and keeps the dryer away from everyone. She then has the cable and the socket checked by an electrician before using either again. Nobody else needed to touch her or the appliance while it was live.

What people get wrong

The common mistake is to rush in and grab the person. Electrical Safety First says never touch someone who is still in contact with the electricity source, because you could suffer a shock too. Cut the supply first, then help.

The second mistake is to assume a shock that left no mark did no harm. The charity says the effects may not be immediately obvious, which is why a conscious person who seems well should still be monitored.^{[1]Electrical Safety First, Electrical Safety First Aid}

The bottom line

Electric shock is current passing through the body, and at home it usually comes from a fault in an appliance, a cable or the wiring. Cut the supply before you touch anyone, call 999 if they are unconscious, and keep watching anyone who seems well. An RCD limits how long current flows but does not make you immune. Any fault behind a shock needs a registered electrician.