Regulations · 4 min read · Updated 6 November 2026
Outdoor socket for a hot tub: UK rules, RCDs and typical costs
What a hired hot tub needs
- A weatherproof outdoor socket, normally 13 amp
- Protection by a 30 mA RCD, either built into the socket or at the consumer unit
- The socket close enough for the tub's own lead and plug to reach without strain
- A circuit that is not already heavily loaded by other outdoor equipment
- For hard-wired hard-shell tubs, a dedicated circuit installed by an electrician
Many inflatable tubs have an RCD device built into the plug or lead, often called a PRCD. This is an extra layer of protection and is not a reason to skip a proper socket.
Why extension leads are a bad idea
A heater of around 2 to 3 kW draws a lot of current for hours at a time. Household extension leads, especially coiled cable reels, can overheat when used near their limit for long periods. Outdoors, connections can also get wet. Most hot tub manufacturers and hire companies say not to use a standard extension lead at all.
- Coiled reels can overheat even below their rated load
- Indoor extension leads are not designed to be outdoors
- Running a lead through a window or door crushes the cable and creates a trip hazard
- Water on plugs and sockets is a serious shock risk
If the supplier says an extension lead is fine without any checks, treat that as a warning sign.
Some people ask about heavy-duty outdoor extension leads. Even these are not a substitute for a fixed outdoor socket for a hot tub, because the connection still sits on the ground, the lead is a trip hazard and most hot tub instructions specifically say not to use one. If the socket is a little too far away, the fix is to move or add a socket, not to extend the lead.
The rules in brief
In England, electrical work in homes falls under Part P of the Building Regulations. Installing a new circuit, replacing a consumer unit, or work in certain special locations is notifiable, which means it must be done by an electrician registered with a competent person scheme, or notified to building control. The IET's guidance on hot tubs says that an outdoor hot tub location should be treated using the special location requirements for swimming pools in the wiring regulations.
| Job | Typically notifiable in England? |
|---|---|
| New dedicated circuit for a hot tub | Yes |
| Replacing the consumer unit | Yes |
| Adding an outdoor socket to an existing circuit | Often not, but ask your electrician |
| Like-for-like replacement of a damaged socket | No |
Rules differ slightly in Wales, and Scotland has its own building standards system. A registered electrician will know what applies and will provide certification for notifiable work.
Typical costs
| Job | Typical guide price (2026) |
|---|---|
| Outdoor socket on an outside wall, short run | £120 to £250 |
| Outdoor socket with a longer cable run | £200 to £450 |
| Dedicated circuit for a hard-wired hot tub | £400 to £1,200 or more |
| New consumer unit if needed | £400 to £900 |
Prices vary by region and depend on the distance from the consumer unit, wall construction and whether cable has to be buried. Buried cables need protection and proper depth, which adds cost.
Before your hire
- Check you have an outdoor socket and test it with a plug-in RCD tester or by pressing its test button
- Measure from the socket to where the tub will go
- Tell the supplier the distance when booking
- If there is no socket, book an electrician at least a week or two before the hire
- Do not let anyone run the tub from an indoor socket through a window
Ask the electrician to check the circuit as well as fit the socket. If the outdoor socket shares a circuit with a kitchen, garage or other heavy loads, the tub may trip the circuit when everything is running at once. A short check now avoids a cold tub halfway through the hire.
Safety during the hire
- Keep the plug and socket off the ground and away from splashes
- Do not touch the plug or controls with wet hands
- Press the RCD test button at the start of the hire if the supplier advises
- Switch off and unplug before the supplier drains or moves the tub
- Never use the tub if a lead or plug is damaged, and call the supplier
Frequently asked questions
Can I use an extension lead for a hired hot tub?
It is strongly advised not to. Hot tub heaters draw a high current for long periods, and household extension leads, particularly coiled reels, can overheat. Leads run outdoors or through windows can also get wet or crushed. Most manufacturers and hire companies require the tub to be plugged straight into a suitable RCD-protected outdoor socket.
Do I need an electrician to install a hot tub socket?
You should use a qualified electrician. In England, a new circuit or work in a special location is notifiable under Part P, so it must be done by a registered electrician or notified to building control. Even where a simple outdoor socket is not notifiable, outdoor electrics are high risk, so a registered electrician is the safe choice.
What is an RCD and why does a hot tub need one?
An RCD, or residual current device, switches the power off very quickly if it detects current leaking to earth, for example through a person. Outdoor sockets in homes are normally required to be protected by a 30 mA RCD. Because hot tubs combine water and electricity, RCD protection is an essential safety measure.
outdoor socket RCD Part P electrical safety
