Electric showers and cookers are the two heaviest loads in most homes, and the two appliances people most often connect wrongly. A modern 9.5kW or 10.5kW shower draws more current than everything else in the house combined, and an induction hob is not far behind. Undersized cable, a tired isolator or the wrong breaker rating is a genuine fire risk, and the failure we see most often when we open up a scorched shower switch.
Getting it right is a matter of arithmetic and workmanship: cable sized to the load and the run (typically 10mm twin and earth for larger showers, 6mm or 10mm for cookers), a breaker or RCBO matched to the cable, a proper double-pole isolator, and terminations torqued and checked because these circuits run hot for long periods.
We install, replace and upgrade shower and cooker circuits across Greater London. That includes like-for-like swaps, upgrading circuits when you move to a more powerful shower or from gas to induction, and honest advice when your circuit cannot take the appliance you have bought.
What's included
Load and circuit assessment first
Before anything is bought or booked, we check the appliance rating against the existing cable size, breaker and main fuse. A 10.5kW shower on a circuit installed for a 7kW unit is not a swap, it is a rewire of that circuit, best known before purchase.
Correctly sized new circuits
Where a new or upgraded circuit is needed, we run correctly sized cable from the consumer unit with RCD protection, which BS 7671 requires for shower circuits and is good practice for cookers.
Proper isolation
Double-pole pull-cord isolators for showers (mounted where they can actually be reached) and 45A cooker control switches within reach of, but not directly above, the hob. Old, crackling isolators are replaced, not reused.
Appliance connection and setup
Showers connected and commissioned to the manufacturer's instructions, hobs and ovens connected at the outlet plate with correct terminations, and everything function-tested before we leave.
Testing and certification
Full circuit testing to BS 7671 with a Minor Works Certificate for connections to existing circuits or an Electrical Installation Certificate for new circuits, plus Building Regulations notification where the work is notifiable.
How the job runs
- 1
Send us the details
The appliance model or kW rating, plus photos of your consumer unit and the existing switch or connection point, tells us whether it is a simple connection or a circuit upgrade.
- 2
Fixed quote
You get a written price for the exact scope: connection only, isolator replacement, or a new circuit including the cable route we would take. No on-the-day extras.
- 3
Installation
A like-for-like connection takes an hour or two. A new shower or cooker circuit is typically half a day to a day depending on the route. Water and power are only off for the final connections.
- 4
Testing and commissioning
The circuit is dead and live tested, RCD operation is verified, and the appliance is run through its functions so you see it working before we sign it off.
- 5
Paperwork
You receive the certificate for the work, and notification is handled where the job is notifiable.
What it costs
Installation starts from £140 for a straightforward connection, such as replacing a cooker or shower on an existing, adequate circuit. Most jobs come in between £150 and £450. The top of the range is a new circuit: a powerful shower far from the consumer unit means a long run of 10mm cable, expensive per metre and slow to route neatly.
What moves the price: whether the existing circuit is adequate (the single biggest factor), cable run length and route difficulty, whether the isolator or cooker switch needs replacing, and whether the consumer unit has a suitable spare way with RCD protection. The full price is confirmed in writing before work starts, and if we find the existing circuit is dangerous, we price the fix before touching it.