What is this?
Electric showers are high-power appliances, typically drawing 8.5kW to 10.8kW on their own dedicated circuit. When a shower trips the electrics, it usually means there is an earth fault in the shower unit, the wiring, or the connections. Because showers operate in a wet environment, earth faults are both more likely and more dangerous. The RCD is doing its job by detecting the fault and cutting the power before it can cause harm.
Common causes
- Water ingress into the shower unit or its electrical connections
- Heating element in the shower has failed and is leaking current to earth
- Loose or corroded connections in the shower isolator switch or junction
- Cable to the shower has been damaged (e.g., by a nail or screw through the wall)
- Shower unit is old and insulation has degraded internally
Is it dangerous?
A shower that trips the electrics should not be used until the fault is found and fixed. Water and electricity are a dangerous combination, and the RCD is tripping because it has detected current flowing to earth — potentially through the water or through you. Never bypass the RCD or remove it to keep the shower working. The protection is keeping you safe.
Can I fix it myself?
No. Electric showers are connected to high-current dedicated circuits (usually 40A or 45A) and must be worked on by a qualified electrician. Do not open the shower unit or attempt to dry it out. Turn off the shower isolator switch and leave it off until an electrician has investigated.
When to call an electrician
Call an electrician if your shower trips the electrics even once. While a single trip could be a one-off (e.g., water splash during installation), repeated tripping indicates a fault that needs professional diagnosis. Do not keep resetting and trying the shower.
What will an electrician do?
Isolate the shower circuit and test the wiring for insulation resistance
Inspect the shower unit connections and internal components
Check the shower isolator switch and cable for damage or water ingress
Replace the shower unit if the heating element has failed
Test the circuit after repair to confirm safe operation
Verify the shower circuit has its own dedicated MCB and RCD protection
Typical cost
£80 – £350
Fault-finding and connection repair at the lower end. If the shower unit needs replacing, the unit itself costs £100–£250 plus installation.
