Can I just swap my old electric shower for a new one?
Usually, yes. If the new shower has the same or a lower kW rating and the existing circuit was installed properly, it's normally a straight swap done in a few hours.
A common job is replacing an old shower that has packed up with a new one on the same supply. Before we connect anything, we check that the circuit is still right for the new unit. Most of these checks take minutes, but they are the difference between a shower that works safely for years and one that overheats at the terminals.
- Cable size
- Must be big enough for the shower's current over the length of the run.
- Breaker or fuse rating
- Has to match the shower and protect the cable.
- RCD protection
- Current rules call for 30mA RCD protection on bathroom circuits.
- Isolating switch
- A double-pole switch, usually a ceiling pull-cord, rated for the shower.
- Terminals and cable ends
- Scorching on the old unit points to a loose connection to sort first.
- Water pressure
- Each shower needs a minimum mains pressure, set by the manufacturer.
Can I fit a more powerful electric shower?
Sometimes, but only if the cable and breaker can carry the extra current. A higher kW rating means more current, so moving up from an 8.5 kW to a 10.5 kW shower often means a new cable back to the fuse box.
As a rough guide, 8.5 kW, 9.5 kW and 10.5 kW showers draw around 37, 41 and 46 amps at 230 volts. A 10.5 kW shower commonly needs 10 mm² cable, while 6 mm² can be enough for lower ratings on a short, well-installed run. The exact answer depends on how long the cable is, how it's run and what protects it, which is why we check before we price.
If the existing circuit isn't big enough, you have two options: choose a shower that suits the circuit you have, or have a new circuit installed. A new circuit is notifiable under Part P, and we'll explain the route the cable would take before you decide.
Why has my electric shower stopped working?
The usual causes are a tripped breaker or RCD, a burnt-out heating element, a failed pressure switch or a loose, overheated connection. Some are repairable, but on an older shower a replacement is often the more sensible fix.
If you smell burning or see scorch marks on the shower or the pull-cord, switch off at the pull-cord and at the fuse box and don't use it until it's been checked. Otherwise, these are the faults we see most:
- Runs cold only
- Often a failed heating element or thermal cut-out.
- Won't switch on
- Check the pull-cord and the breaker first; then a pressure switch or power fault.
- Trips the RCD
- Usually water getting into the unit or a breakdown in the element.
- Very low flow
- Limescale in the head or inlet filter, or low mains pressure.
- Temperature swings
- Pressure changes when other taps run, or a worn stabiliser valve.
Electric shower or pumped shower: which suits my home?
An electric shower heats cold mains water as it flows, so it works on its own without the boiler. A pumped (power) shower boosts water stored in a hot water cylinder and cold tank, so it only suits homes with that kind of system.
With a combi boiler, there is no stored hot water to pump, so the choice is usually an electric shower or a mixer shower fed by the combi. Many homes keep an electric shower as a second shower, or as a backup for when the boiler is out of action. Pumps generally shouldn't be connected straight to the mains supply under the water regulations.
- Electric shower
- Heats mains water on demand. Flow is limited by the kW rating.
- Pumped shower
- Strong flow from stored hot water. Needs a cylinder and cold tank.
- Mixer shower
- Mixes hot and cold from a combi or unvented cylinder; no pump needed.
Does fitting an electric shower need Part P notification?
A new shower circuit does, and so does most new electrical work in a bathroom. A straight replacement on a suitable existing circuit usually doesn't, but it still has to be safe and tested.
Part P of the Building Regulations covers electrical safety in homes, and bathrooms are treated as a special location because water and electricity are close together. The work is done to the current Wiring Regulations (BS 7671, 18th Edition), and you get a certificate showing the test results.
Where the rules on a particular job aren't clear-cut, such as a swap that also needs the cable extended, we'll tell you which applies when we price it.
How does Leicester's hard water affect an electric shower?
Leicester is supplied by Severn Trent and the water is hard, so limescale builds up in the shower head, the inlet filter and the heater. Over time that cuts the flow and makes the shower work harder.
A few habits help a shower last longer. Clean or descale the head regularly, following the maker's instructions. Many showers have a short run-on after switching off that flushes hot water out of the heater, so let it finish rather than isolating the power straight away. If the flow has dropped steadily over months, scale is often the reason, and the inlet filter can usually be cleaned when we visit.
What affects the price of an electric shower installation?
The biggest factor is whether the existing circuit can be reused.
We give you one fixed price before any work starts. These are the things that move it:
- Swap or new installation
- Reusing the supply and position is simplest.
- Change in kW rating
- A bigger shower may need new cable and protection.
- Cable route
- Distance from the fuse box and whether floors need lifting.
- Your consumer unit
- A spare way and RCD protection keep the job simpler.
- Pipework and holes
- Moving the inlet or covering old fixing holes adds time.