Replacing an electric shower looks like a simple swap: take the old unit off the wall, fit the new one, switch it back on. Sometimes it is that straightforward. But an electric shower is one of the biggest electrical loads in a home, so the parts you cannot see — the cable, the protective device at the consumer unit and the isolator — decide whether it is a quick job or something that needs more planning.
This guide covers what is involved, how long it usually takes, who should do it, and what to check before you buy a new unit. RIGS Electrical is a NICEIC registered domestic electrician based in Tring, working across Hertfordshire, Buckinghamshire and nearby border areas.
Signs your electric shower needs replacing
Scale build-up, worn components and age all take their toll, especially in hard water areas. Common signs include:
- The temperature keeps changing or swings between hot and cold on its own
- The flow has dropped, even after cleaning the shower head
- The unit has stopped heating or will not start
- The shower trips the RCD or circuit breaker when switched on
- Water is leaking from the casing or the pressure relief device has operated
- There is a burning smell, scorch marks or discoloured plastic on the unit, isolator or pull-cord switch
The last one is not a "replace it soon" sign. Stop using the shower, switch it off at the isolator and consumer unit if you can do so safely, and get it checked — overheating connections are a fire risk. Our guide to whether you need an emergency electrician or it can wait helps you judge the urgency.
Is it a like-for-like swap or more than that?
The key question is whether the existing circuit suits the new shower. Domestic electric showers are commonly rated somewhere between about 7.5 kW and 10.8 kW. A higher rating draws more current, so the cable and the breaker or RCBO feeding it must be rated to match.
An electrician will typically check:
- The new rating against the old one. Moving from an older 7.5 kW or 8.5 kW unit to a 9.5 kW or 10.5 kW model is where most problems start.
- Cable size and installation method. The right cable depends on the rating, the length of the run and how it is routed, for example through loft insulation. A cable that suited the old shower may be undersized for a more powerful one.
- The protective device at the consumer unit, which must suit both shower and cable.
- RCD protection. BS 7671, the UK Wiring Regulations, requires 30mA RCD protection for circuits serving a room containing a bath or shower. Older boards often lack it.
- The isolator. Electric showers need a suitable double-pole isolating switch, usually a ceiling pull-cord or a wall switch outside the bathroom. Old pull-cord switches are a common hot spot.
- The consumer unit itself. If the board is old, full or uses rewireable fuses, a shower upgrade can be the point where a consumer unit replacement makes sense.
If everything checks out and the swap is like for like, the job is mainly removing the old unit, connecting the new one to the existing water and electrical supply, and testing. If the cable or protection is not suitable, it becomes a circuit upgrade, which takes longer and needs certifying.
How long does it take to replace an electric shower?
As a general guide:
- A like-for-like replacement on a suitable circuit is usually a few hours, including testing.
- A higher-rated shower needing a new cable or protective device can take most of a day, depending on how easily the cable can be routed from the consumer unit to the bathroom.
- A shower fitted somewhere new, or as part of a bathroom refit, depends on the wider project. The electrical first fix needs doing before walls are tiled or boarded.
Access is the biggest variable: runs through lofts and floor voids are quicker than lifting floorboards or chasing walls. We confirm the scope after seeing the existing setup.
Can you replace an electric shower yourself?
In England, replacing an existing electric shower like for like on a suitable circuit is generally not notifiable under Part P of the Building Regulations. A new circuit or a consumer unit replacement is notifiable, so it needs a registered electrician who can self-certify it, or building control sign-off. Wales applies its own version of the rules. Our guide on what electrical work needs Part P certification explains more.
"Not notifiable" does not mean "anyone can do it". The work must still be safe and meet BS 7671. Many shower problems come from earlier swaps where a more powerful unit was connected to a cable never designed for it, so if you are unsure about your circuit, get that answered before you buy.
Where should the new shower be mounted?
Mounting height and position come from the manufacturer's installation instructions, relative to the shower head, riser rail and water inlet, and the unit must suit its bathroom zone. Fitting it where the old one was usually keeps the existing cable and pipe entries usable.
Choosing the replacement unit
Before you buy, note the rating of your current shower (printed on the unit or in the manual), decide whether you want more power, since that drives the circuit checks above, and check that the cable and pipe entry points line up. Each unit also lists a minimum water pressure.
Still deciding between electric and mixer? Our article on why an electric shower might be right for your home compares the two.
Paperwork when the work is done
The circuit should be tested after a replacement. Work on an existing circuit is usually recorded on a Minor Electrical Installation Works Certificate. A new circuit should come with an Electrical Installation Certificate and, because it is notifiable, a Building Regulations Compliance Certificate through the electrician's scheme. Keep these with your house documents.
Replacing an electric shower in Tring and nearby
If your shower is failing, tripping, or you want a more powerful model, RIGS Electrical can check whether your circuit is suitable and replace the unit safely. See our electric shower installation service or electric shower installation in Tring. If the shower keeps tripping and you are not sure why, electrical fault finding is often the right first step.
Send us the make and rating of your current shower, a photo of your consumer unit if you can, and the model you are considering, and we will advise on what is needed and provide a clear quote.
*Regulatory summaries reflect guidance for England at the time of writing. This is general information, not legal advice. Always follow the shower manufacturer's installation instructions.*