Stop if there is heat, burning, arcing, exposed parts or water near electrical equipment
Fixed appliances can draw high current and may remain connected even when their controls appear off. Do not remove covers or test exposed conductors. Leave affected circuits isolated and call a registered electrician or qualified appliance engineer where fixed wiring or internal faults are suspected.
MOST LIKELY CAUSES
Start with these
Symptom variations Match the exact behaviour before testing. ⌄
- Trips immediately when switched on
- Trips only on hot settings
- Trips after running for a few minutes
- RCD trips rather than breaker
- Shower switch or cable feels hot
Quick checks Safe checks using controls and front-panel devices only. ⌄
- Check the appliance control panel, timer, thermostat and child-lock settings.
- Confirm the local isolator or fused spur is on and undamaged.
- Inspect the consumer unit for a tripped breaker, RCBO or RCD.
- Look for heat, smell, moisture, buzzing or discolouration.
- Attempt one controlled reset only if no danger signs are present.
Fix 1 — Leave the shower off after repeated trips Follow this check without opening live or fixed electrical equipment. ⌄
Process
Do not continue resetting the breaker or RCD.
Fix 2 — Check for visible moisture or heat Follow this check without opening live or fixed electrical equipment. ⌄
Process
Inspect externally for leaks, scorching or discolouration.
Fix 3 — Separate shower and supply symptoms Follow this check without opening live or fixed electrical equipment. ⌄
Process
Note whether tripping occurs at the isolator, when flow starts or when heat is selected.
Common causes explained Why the appliance or circuit may fail. ⌄
Repeated tripping from an electric shower usually points to a failing heating element, water ingress, insulation breakdown, overheated isolator, damaged cable or internal short circuit.
Fixed appliances often use dedicated circuits, high-current isolators, fused spurs or local controls. The fault may be in the appliance, the control accessory, the cable or the circuit protection.
Advanced diagnostics Technician-level testing for a competent electrician. ⌄
- Insulation-resistance testing of the shower and circuit.
- Heating-element resistance and earth leakage checks.
- Full-load current measurement.
- Inspection of isolator, terminals and cable heat damage.
- RCD/RCBO trip testing and circuit verification.
Parts that may need replacing Common components linked to this fault. ⌄
- Heating element
- Shower isolator
- Cable section
- Breaker or RCBO after testing
- Thermal cut-out
- Complete shower unit
When to call an electrician or appliance engineer Conditions that should end DIY troubleshooting. ⌄
- The appliance or isolator is hot, burnt, buzzing or crackling.
- The breaker, RCBO, RCD or fused spur operates repeatedly.
- Water may have reached electrical components.
- The appliance is permanently wired or high current.
- The fault remains after simple control and supply checks.
- Internal covers or fixed wiring would need to be opened.
Frequently asked questions Common questions about fixed appliances. ⌄
Can the appliance be faulty even when the breaker stays on?
Yes. Controls, elements, motors and internal connections can fail without operating circuit protection.
Should I repeatedly reset a dedicated circuit?
No. One controlled reset is enough to confirm whether the fault remains.
Can I fit a larger fuse or breaker?
No. Protection must match the cable and appliance design. Increasing it can create a fire risk.