Can you run an inflatable hot tub on an extension lead?

What makers say

Inflatable tub manuals from the main brands generally tell you to plug directly into a suitable socket and warn against extension leads, adapters and multi-way blocks. Some allow a specific type of outdoor rated lead under conditions. Check your own manual, as using the tub against the instructions may affect safety and warranty.

The plug on many tubs has an RCD built in. That protects against some faults but does not make an unsuitable lead safe.

Why hot tubs are a hard load

A 13 A plug can supply about 3 kW. An inflatable tub's heater is often rated at roughly 2 kW, and the pump adds to that. The heater can run for many hours at a time, especially when heating from cold. That is a long, heavy load compared with most garden tools.

Cheap or thin extension leads may not be rated for 13 A continuously. Coiled cable reels heat up when used without fully unwinding, which can melt insulation. Outdoors, connections can let in rain and condensation.

Risks at a glance

The safer option

Have a qualified electrician fit a weatherproof outdoor socket with RCD protection, within reach of the tub's supplied cable. They can check the circuit can carry the load and place the socket where it will not be splashed. Many owners find this is a modest job compared with the cost of the tub.

If the tub keeps tripping the electrics, see hot tub tripping the RCD. For larger tubs that need more power, see 13 amp vs 32 amp.

Note:Hot tubs combine water and mains electricity. Use a weatherproof outdoor socket protected by an RCD, follow the maker's manual, and have any new circuit or socket fitted by a qualified electrician.

Plan the spot around the socket

Choosing where the tub goes often decides the electrics. Measure the supplied cable before you buy and set the tub where it reaches the socket without strain. Keep the cable off the ground where possible, out of walkways and away from the drain point.

Our base ideas page helps you pick a spot, and our best inflatable hot tubs guide lists models you can compare.

See the best inflatable hot tubs →

If you already used a lead

Stop and check it. Unplug the tub, then look at the lead, plug and socket for discolouring, melting or a hot smell. Do not keep using a lead that has run warm. Book an electrician to fit a proper outdoor socket before using the tub again.

While you wait, keep the cover on so the water holds its heat. A well insulated tub loses heat more slowly; see how to insulate an inflatable hot tub.

Cable length and placement tips

Before buying, check the length of the power cable on the tubs you are considering; listings and manuals usually state it. Then measure from your preferred spot to the nearest outdoor socket. If it is too far, it is usually better to move the tub or add a socket than to bridge the gap.

Keep the plug and RCD off the ground and out of puddles, and route the cable where it will not be stepped on or caught by the cover. Never run a cable under the tub or ground mat.

Frequently asked questions

Can I plug my inflatable hot tub into an extension cord? Most makers advise against it. Plug directly into a suitable outdoor socket with RCD protection, and check your manual.

What about a heavy duty outdoor extension lead? Some manuals allow specific leads under conditions, but most say not to. An electrician fitted outdoor socket is safer.

Why does my extension lead get warm? The tub draws a heavy load for hours. Warmth is a warning sign; stop using it.

Is the RCD on the plug enough protection? It protects against some faults but does not make an unsuitable lead safe. Use a proper socket.