What is this?
When an electric shower stops working completely, it has lost power. This could be because the shower circuit MCB has tripped, the shower isolator switch has been turned off, or there is a fault in the wiring or the shower unit itself. Electric showers run on a dedicated circuit, so a shower failure does not usually affect other appliances.
Common causes
- Shower circuit MCB has tripped in the consumer unit
- Shower isolator switch (pull-cord or wall switch) is turned off
- Heating element has failed (common after 5+ years of use)
- Loose or burnt connection at the isolator or shower terminal
- Thermal cut-out (TCO) inside the shower has activated due to overheating
Is it dangerous?
A shower that has simply lost power is not immediately dangerous. However, do not attempt to open the shower unit to investigate — it operates at mains voltage on a high-current circuit. If the MCB has tripped, there may be an underlying fault. If you notice a burning smell or discolouration on the isolator switch, do not use the shower until an electrician has inspected it.
Can I fix it myself?
Check the shower isolator switch is in the on position (the neon indicator light should be on). Check the consumer unit for a tripped MCB on the shower circuit. If neither of these resolves the issue, the fault is in the shower unit or wiring and you need an electrician. Do not open the shower unit.
When to call an electrician
Call an electrician if resetting the MCB does not restore the shower, if the MCB trips again immediately, if the isolator switch is hot or discoloured, or if you suspect a wiring fault. The electrician can diagnose whether the shower unit needs replacing or if there is a connection issue.
What will an electrician do?
Check the shower circuit from consumer unit through to the shower unit
Test the isolator switch and connections for continuity and signs of overheating
Inspect the shower unit internally for failed components (heating element, TCO, flow switch)
Replace the shower unit if it has failed beyond economic repair
Test and certify the circuit after any work
Typical cost
£80 – £400
Diagnosis and connection repair at the lower end. Shower replacement including the unit costs £200–£400. Fitting a new shower to an existing circuit is quicker than a first-time installation.
