Why Is My Electric Shower Not Working?

An electric shower heats water as it flows, using a powerful element that draws one of the largest loads in the house. When something goes wrong, the shower may go cold, cut out mid-wash, refuse to start or trip the power. Some causes are simple. Others mean the shower or its circuit needs an electrician. This guide explains the usual suspects and the checks that are safe for you to make.

First: is the power getting there?

Check the consumer unit. If the breaker or RCD for the shower has tripped, reset it once. If it trips again straight away, or trips the next time the shower runs, leave it off: something on the shower or its circuit is faulty. Also check the pull-cord or wall isolator switch is on. These switches carry a heavy current every day and their contacts wear; a switch that has to be pulled several times or feels loose may be failing.

Danger signs: stop using the shower

If the pull-cord switch or isolator feels warm, looks scorched or discoloured, crackles when operated, or there is a burning smell near the shower, the cable or a connection may be overheating. Stop using the shower, switch it off at the consumer unit if it is safe to do so, and call an electrician. The same applies if you see water leaking from the shower case. Do not take the cover off the unit.

The shower runs but stays cold

Most electric showers have a thermal cut-out that switches the heater off if the unit gets too hot, protecting it from damage. It can operate if the water flow drops, if scale has built up or if a component is failing. Some cut-outs reset themselves when the unit cools; others need resetting by an engineer. A shower that runs only cold, even at the lowest flow setting, may also have a failed heating element.

Scale and water flow

In hard-water areas, scale builds up inside the showerhead and the unit. Restricted flow means the water heats more than it should, triggering the cut-out, and can make the temperature swing between hot and cold. Cleaning or descaling the showerhead, following the manufacturer's instructions, is a safe and worthwhile check. Low mains water pressure, a partly closed stop valve or a kinked hose can cause similar symptoms.

Element failure

Heating elements wear out. A failed element can stop the shower heating at all, or cause it to trip the RCD if water reaches the live parts inside. Element replacement involves opening the unit and is a job for a qualified person; on an older shower, replacing the whole unit is often better value.

Why does my electric shower keep tripping?

Repeated tripping usually points to one of three things: water getting into the unit or its connections, a failing element, or a problem with the cable or switch on the circuit. Occasionally, an old shower circuit isn't suitable for a replacement shower with a higher rating. Our guide to why the RCD keeps tripping explains tripping in general.

Replacing with a higher-rated shower

Swapping to a more powerful shower can need a larger cable and different protection. Fitting a higher kW unit to an existing cable that isn't rated for it can cause overheating. Our electric shower installation page explains what we check before fitting a new unit.

Safe checks, in summary

Reset a tripped breaker or RCD once. Check the pull-cord or isolator is on. Clean the showerhead. Make sure the water supply is fully on. If none of that works, or there are any signs of heat, burning or leaking, leave the shower off and call. Our fault finding service can test the circuit.

Low pressure and temperature swings

Electric showers are sensitive to water pressure. If someone runs a tap or flushes the toilet while the shower is on, the flow drops and the shower may go suddenly hot or trigger its cut-out. That is normal behaviour rather than a fault, but if it happens with nothing else running, the incoming supply or a blocked filter inside the shower may be the cause. Some units have a small inlet filter that a plumber or engineer can clean.

Lights and indicators on the unit

Many showers have indicator lights or display codes that point to a particular fault. Check the user manual or the manufacturer's website for what each one means before calling; it helps us diagnose the problem faster.