Hot water on demand, independent of your boiler, and energy used only when you need it — it's easy to see why electric showers have become a fixture in millions of UK homes. Whether you're upgrading an ageing unit or fitting one for the first time, the process is manageable for a competent DIYer. That said, there are important legal and safety requirements that make professional involvement essential at key stages.
This guide from Asturias Bathrooms walks you through everything: from understanding UK compliance rules and gathering your tools, to running pipework, making electrical connections, and testing the finished installation. By the end, you'll have a clear picture of what you can tackle yourself and what absolutely requires a qualified professional.
Understanding Compliance: Part P and Why It Matters
Before any work begins, you need to understand your obligations under Part P of the Building Regulations (Approved Document P: Electrical Safety – Dwellings). Under UK law, certain electrical work in dwellings is classified as notifiable work and requires certification as compliant with the Building Regulations.
Specifically, the installation of a new circuit — which a new electric shower requires — is notifiable. This applies even when the shower is being installed in a bathroom for the first time. Any addition or alteration to existing circuits within a bathroom (a "special location" under the regulations) is also notifiable.
To certify notifiable work, one of three routes must be followed:
- Self-certification by a registered competent person (e.g. a Part P-registered electrician)
- Third-party certification by a registered certifier appointed before work begins
- Certification by a building control body, which must be notified before work starts
What this means in practice: a qualified, Part P-registered electrician must make the final connection to the consumer unit and issue the appropriate certification. You may be able to carry out the mechanical and preparatory work yourself, but the electrical sign-off is not optional.
Failing to comply can invalidate home insurance, create problems when selling the property, and — most critically — put lives at risk.
Essential Preparation: Tools and Equipment Checklist
Having the right tools to hand before you start saves time and prevents unnecessary interruptions. Here's what you'll need:
For a like-for-like replacement:
- Electric shower unit and manufacturer's manual
- Screwdriver set (flat-head and Phillips)
- Pencil
- Wire snips
- Safety gloves and eye protection
For a new installation from scratch, also add:
- Drill with a masonry bit (and a tile bit if drilling through tiles)
- Reciprocal or jab saw
- Adjustable wrench
- Pipe cutter
- 15mm push-fit pipe and fittings
- Isolating valve
- Pipe and cable detector
Always check the specific requirements in your shower unit's installation manual. Modern units from leading brands often include SmartFit™ or multi-entry technology — such as those in our electric shower range — which can significantly speed up installation by offering flexible left- or right-hand cable and water entry points.
Pre-Installation Safety: Isolating Water and Power
Cutting corners at this stage is not an option. Both your water supply and electrical supply must be fully isolated before any work begins.
Step 1: Isolate the electrical supply. Locate the shower's dedicated circuit breaker at the consumer unit and switch it off. If you are uncertain which breaker controls the shower circuit, use a non-contact voltage tester to confirm the supply is dead before touching any wiring.
Step 2: Isolate the cold water supply. Find the isolating valve on the pipework leading to the shower — often located under the bath panel, behind a panel, or in an airing cupboard. Turn it to the closed position (slot perpendicular to the pipe). Open a nearby tap to release any residual pressure.
Step 3: Verify both supplies are off. Do not proceed until you are completely satisfied that power and water have been safely isolated.
Positioning and Plumbing: Templating and Running the Water Supply
If you are replacing an existing electric shower, the pipework and cable routing should already be roughly in the correct positions. For a brand-new installation, additional planning is required.
Mark the position: Remove the front cover of the shower unit, then hold the backplate against the wall and align the cable entry and water inlet with your planned routing. Many units come with a paper template to simplify marking — use this if available. Mark screw hole positions clearly with a pencil.
Drilling: Using a masonry bit (or tile bit for tiled walls), drill the marked fixing holes. Insert wall plugs. Before drilling any access holes for pipework or cabling, use a pipe and cable detector to check for hidden services in the wall.
Running the 15mm cold-water supply: Electric showers connect to the cold mains supply, not the hot-water system. Run a 15mm copper or plastic push-fit pipe from the cold rising main to the shower position. Fit an isolating valve in the supply line so the shower can be serviced without shutting off the entire water supply. Connect the inlet pipe to the shower unit's cold-water inlet, ensuring a secure, watertight connection. Depending on your installation, a double check valve may also be required to prevent backflow in line with water regulations.
Loosely fix the shower backplate to the wall at this stage, allowing slight adjustment while you finalise connections.
Electrical Wiring: Cabling and the Consumer Unit Connection
This is the stage where professional involvement becomes legally required.
What a competent DIYer can do: Feed the shower cable through the wall access hole and route it to the shower unit. Inside the unit, connect the three cores to their corresponding terminals — brown (live), blue (neutral), and green/yellow (earth). Ensure each connection is firmly secured in its terminal. Tuck any excess cable neatly back into the wall.
The shower must be permanently connected via a double-pole isolating switch with a contact gap of at least 3mm in both poles. This switch must be accessible but out of reach of a person using the shower — a ceiling-mounted pull-cord switch is the most common solution and must not be positioned within electrical zones 1 or 2.
Cable sizing matters: For showers rated above 8kW, a minimum cable size of 10mm² is strongly recommended. A 30 mA RCD (Residual Current Device) should be installed on all electric shower circuits. If you are upgrading from a lower-rated shower, it is essential to check that the existing cable is adequate for the increased load.
What requires a qualified electrician: The final connection from the shower circuit to the consumer unit, and all associated testing and certification, must be carried out by a Part P-registered electrician. This is non-negotiable under UK Building Regulations.
Final Assembly and Testing
With the plumbing connected, the wiring terminated, and the electrician's work complete and certified, you can move to final assembly.
Fitting the shower cover: Replace the unit's front cover, ensuring any dials align correctly with their spindles. Secure with screws.
Fitting the riser rail and hose: Most units include two wall brackets that the riser rail slots into — fix these to the wall at the appropriate height, one above the other. Screw the shower hose into the outlet on the unit body, connect the handset, and clip the hose retainer into place.
Testing: Restore the water supply by reopening the isolating valve, then ask your electrician to restore power to the shower circuit. Turn the shower on and let the water run for a couple of minutes. Check carefully around all pipe connections and the base of the unit for any signs of leakage. If everything looks good and the shower functions correctly, the installation is complete.
Frequently Asked Questions
Can you fit an electric shower yourself?
You can carry out the mechanical and preparatory work — including mounting the unit, running the cold water supply pipe, and routing the cable — provided you are a competent DIYer. However, the final electrical connection to the consumer unit, and the certification of that work under Part P of the Building Regulations, must be completed by a qualified, Part P-registered electrician.
Do I need an electrician or a plumber to fit an electric shower?
Both trades may be involved. A plumber can handle the water supply pipework. However, a Part P-registered electrician is required to make the final connection at the consumer unit and to certify the work. In practice, many qualified electricians are experienced with full installations, including plumbing, so a single tradesperson may be able to complete the job end to end.
Can an electric shower be fitted in any bathroom?
Yes. Because electric showers connect directly to the cold mains supply and heat water on demand, they work with any plumbing system — including homes without a hot water cylinder or those on a combination boiler. They can be installed in a shower enclosure or over a bath. The key requirements are adequate cold water pressure (typically a minimum running pressure of 1.0 bar) and a suitable electrical supply.
Ready to Upgrade Your Shower?
Fitting an electric shower is a satisfying project when approached properly — the right preparation, the right unit, and the right professional for the electrical work.
If you are looking for a unit that combines safety, performance, and ease of installation, the Redring Selectronic Plus Advanced Thermostatic Electric Shower 8.5kW is an excellent choice. Its SmartFit™ technology offers multi-entry flexibility, EAB Care technology maintains temperature to within ±0.5°C, and it carries a Class A energy rating — backed by a 3-year manufacturer's guarantee.
For those seeking something with a more distinctive aesthetic, the Aqualisa Lumi+ Electric Shower Mirrored Chrome 8.5kW features a striking mirrored fascia and integrated light strip that provides visual feedback on temperature and pressure — a genuinely elegant piece of bathroom hardware.
Alternatively, the Redring Glow 8.5kW Thermostatic Digital Electric Shower delivers reliable thermostatic control, phased shutdown anti-scaling technology, and a large LED digital display — all at a highly competitive price point.
Browse the full showers collection at Asturias Bathrooms to find the right model for your bathroom.
