An electric shower heats cold mains water as it passes through the shower unit, using its own electrical supply rather than relying on a hot-water cylinder or boiler. When it stops heating, trips the power or develops a burning smell, the problem may be inside the unit or elsewhere on its circuit. For homeowners, landlords and businesses across London and the M25 area, the priority is to stop using an unsafe shower and establish what has failed. Our 24/7 emergency electrician service deals with electrical shower faults, including problems with the supply, isolation switch and protective devices.
Understanding your electric shower and its supply
An electric shower is different from a mixer shower, which blends existing hot and cold water, and a power shower, which uses a pump to boost water flow. This distinction matters when investigating a fault. If your boiler works but your electric shower runs cold, the boiler is not normally responsible: the shower heats its water independently.
Heating water instantly places a substantial load on the electrical circuit. An electric shower normally needs a dedicated circuit, an appropriately rated cable and protective device, and a suitable means of isolation. A ceiling pull-cord switch or a wall-mounted switch outside the bathroom may control its supply. These components need checking alongside the shower itself; replacing the unit will not resolve a damaged connection elsewhere.
In a London flat, shared house or workplace changing room, the shower's condition is only part of the picture. Previous alterations, the route of the supply cable and the condition of the consumer unit can affect what work is needed. A higher-powered replacement cannot simply be fitted because it occupies the same space on the wall.
Common electric shower faults and what causes them
A shower that runs normally but produces only cold water may have a failed heating element, thermal safety device or internal control. However, low water pressure or restricted flow can also prevent heating on some units. Water that alternates between very hot and cold may indicate a flow restriction, unstable pressure or a fault in temperature regulation. Unexpectedly hot water creates a scalding risk, so stop using the shower rather than trying to tolerate it.
If the shower goes completely dead, possible causes include a supply fault, a defective isolation switch or an internal failure. A pull cord that sticks, a switch that buzzes, or discolouration around the switch can point to worn contacts or overheating connections. An indicator light is not proof that the circuit is safe or that the shower is receiving a sound electrical supply.
A circuit breaker or RCD that trips when the shower starts can indicate overcurrent, electrical leakage, moisture ingress or deteriorating insulation. Repeated tripping is a warning, not something to overcome by resetting the device until it stays on. Drips from the casing or water appearing beneath the unit may involve an internal leak or pressure-relief device. Do not block an outlet, bypass a safety device or continue showering to see whether the fault clears.
When to stop using the shower and get emergency help
If there is smoke, burning, sparking or water near electrics, switch off at the main switch only if safe to do so, keep clear and call an emergency electrician. Do not cross a wet floor, touch wet switches or approach a damaged consumer unit to isolate the supply. Call 999 for a fire. Do not use water to fight an electrical fire or delay leaving the property to investigate the shower.
A tingling sensation or electric shock from the shower, hose, taps or nearby metalwork requires immediate attention. Stop using the bathroom and keep others away. Do not touch someone who may still be in contact with an electrical source. Call 999 if someone is in immediate danger or seriously injured. Arrange an electrical assessment before anyone uses the shower again.
Leaving an overheating terminal or damaged switch in service can allow insulation to deteriorate and increase the risk of fire. An internal leak can bring water into contact with live parts, while a temperature-control fault can cause burns. In shared accommodation or business premises, tell other users that the shower is out of use and prevent accidental operation. A handwritten warning alone is not a substitute for safe isolation.
Safe checks you can make without opening anything
Only make external checks when there is no smoke, burning, sparking, leakage or other sign of danger. With dry hands and from a dry position, note whether the shower display or indicator is on and whether other parts of the property have power. Look at the consumer unit only if it is safely accessible, without removing any covers. Record which protective device appears to have tripped, but do not repeatedly reset it.
Check whether cold water is available at another tap and whether the problem coincides with water being used elsewhere. Note any fault code, unusual sound or change in flow. These observations help distinguish a water-supply issue from an electrical fault, but they do not establish that the shower is safe. If the whole street has lost electricity, call 105 for a street-wide power cut rather than assuming the shower caused it.
Do not remove the shower cover, open the pull-cord switch, tighten terminals or attempt electrical tests yourself. Do not disconnect the hose to release pressure during a suspected fault. Routine showerhead cleaning should follow the manufacturer's instructions and should not be attempted as a remedy for burning, tripping or leakage. When contacting an electrician, describe the symptoms and, if available without opening the casing, provide the unit's model and power rating.
How an electrician repairs or replaces an electric shower
The electrician first establishes the symptoms and safely isolates the relevant supply, verifying that it is dead before accessing electrical components. Investigation can include the shower terminals, isolation switch, cable condition and circuit protection. Electrical testing helps identify insulation faults and assess protective measures. Where water leakage or inadequate pressure is involved, plumbing work may also be needed; electrical repairs alone cannot correct every shower fault.
A repair might involve replacing a damaged isolator, correcting a faulty connection or fitting an appropriate internal component where the unit is suitable for repair. Heat-damaged cable or accessories need assessment rather than simply tightening a terminal and restoring power. Replacement may be more appropriate when the casing or internal assembly is damaged, suitable parts are unavailable, or the fault cannot be safely resolved with a component repair.
Before fitting a replacement, the electrician checks its electrical demand against the existing circuit, including cable capacity, installation conditions and protective devices. Relevant requirements of BS 7671, the IET Wiring Regulations, include protection against electric shock, RCD protection and suitability for a bathroom location. Earthing and bonding arrangements also need assessment. After the work, testing and operational checks establish whether the installation can be returned to use, with electrical certification provided as appropriate to the work undertaken.
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Frequently asked questions
Why does my electric shower trip the RCD?
An RCD detects electrical current leaking away from its intended path. In a shower circuit, this can result from a deteriorating heating element, moisture inside the unit, damaged wiring or another insulation fault. The timing of the trip helps the investigation but does not identify the cause on its own. Stop using the shower and arrange electrical testing instead of repeatedly resetting the RCD.
Can I replace my shower with a more powerful model?
Only after the existing supply has been assessed. A more powerful shower draws more current, and the installed cable, isolation switch or protective device may not be suitable. Cable routing and installation conditions matter as well as cable size. Increasing the breaker rating without checking the circuit is unsafe. Ask an electrician to establish what the installation can support before choosing a replacement.
Does a cold electric shower always need replacing?
No. Cold water can result from an internal heating fault, a control problem or water flow that does not meet the unit's operating requirements. Some faults are repairable, while others make replacement more appropriate. An electrician can investigate the electrical supply and unit, although water-pressure or plumbing problems may need separate attention. Avoid buying a replacement solely on the assumption that the heating element has failed.
Is it safe to use a shower with a buzzing pull-cord switch?
Stop using the shower until the switch has been checked. Buzzing can indicate a defective contact or connection, particularly under the heavy load of an electric shower. Do not open the switch or keep operating it to test the noise. If there is smoke, burning or sparking, switch off at the main switch only if safe, keep clear and call an emergency electrician.
Can an emergency electrician help with a shower fault outside normal working hours?
Our emergency electrician service operates 24/7 across London and the M25 area. Explain whether the shower is leaking, tripping the supply, overheating or completely without power so the immediate risk is understood. The first priority is making the electrical installation safe. Completing a repair or replacement depends on the fault, circuit condition and availability of suitable parts; further work may be necessary.