Hot Tub Electrical Requirements — What You Need Before It Arrives
The most common hot tub mistake is buying the tub first and discovering the electrics second. Here's what your electrician needs you to know.
13A 'plug and play' vs 32A hard-wired
Hot tubs come in two electrical flavours. 'Plug and play' tubs run from a 13A supply — but that does not mean a garden extension lead; manufacturers require a dedicated outdoor-rated RCD-protected supply, and the trade-off is slow heating and heaters that pause while the jets run.
Most full-size tubs are 32A hard-wired: a dedicated circuit from your consumer unit, through a lockable rotary isolator near the tub, into the tub's control pack. Faster heating, full jets and heat together, and lower running frustration. If you're choosing between models, the electrical supply should be part of the buying decision — not an afterthought discovered on delivery day.
What the installation involves
A compliant 32A hot tub supply is a proper piece of electrical work:
- A dedicated circuit from the consumer unit — usually 6mm² or 10mm² SWA cable depending on the run length
- 30mA RCD protection — required for outdoor circuits, and specified by every tub manufacturer
- A weatherproof rotary isolator positioned within sight of the tub (but at least 2m from the water) so it can be safely isolated for servicing
- Burial or protection of the cable route — trenched SWA with marker tape, or protected surface runs
- Consumer unit capacity check — a 32A continuous load is significant; older or full boards sometimes need upgrading first
- Testing and certification — this is a new circuit, so it's notifiable under Part P and certified through our NAPIT registration
What it costs
For a typical installation — tub within 10–15m of the consumer unit, straightforward cable route — expect £450–£800 including the isolator, cabling, connection, testing and certification. Long runs, difficult trenching or a consumer unit upgrade push it higher; we quote a fixed price from photos of your board and the route before any digging starts.
Time it right: get the electrics surveyed when you order the tub, and installed before delivery. Tub delivery crews will position the tub but won't (and shouldn't) connect it — and a full tub sitting unheated in January is a sad sight.
Common questions we get on site
Can it share the garden office supply? Sometimes — if the sub-main was sized with spare capacity; often it wasn't. Can it run from the outdoor socket? No — even plug-and-play tubs need their own dedicated protected supply. Does it affect my consumer unit? A 32A continuous load is the same order as an electric shower; we check capacity as the first step of every hot tub survey.
Planning a tub in London or Kent? Send us a photo of your consumer unit and the proposed tub position, and we'll give you a fixed price — call or WhatsApp 07535 810812.
Frequently Asked Questions
Do I need an electrician for a plug-and-play hot tub?
Usually yes. Manufacturers require a dedicated RCD-protected outdoor supply — not an extension lead — and if a suitable socket doesn't already exist, installing one outdoors competently is electrician's work. It's a small job, but it's the difference between warranty-valid and not.
How long does hot tub electrical installation take?
Most installations are completed in a day, including the isolator, cable run and certification. Trenching across a large garden or a consumer unit upgrade can extend it to two days.
Is hot tub wiring notifiable under Part P?
Yes — a hot tub supply is a new circuit, which is notifiable. We self-certify through NAPIT, so Building Control notification and your compliance certificate are handled automatically.
Talk to a NAPIT-Registered Electrician
Call 07535 810812 or WhatsApp us — free quotes, honest advice, and certified work across London & Kent.