Electrical Guidelines for Hot Tubs

You don’t need a permanent water supply for a Hot Tub but you will need a suitable electrical supply to run the Hot Tub. Hot Tubs have a specific section in the 16th Edition IEE (Institute of Electrical Engineers) Regulations and fall into the same category as swimming pools.

When appointing an electrician to prepare your Hot Tub electrics, check that they are suitably qualified electrician. Do not attempt to install a Hot Tub electrics yourself if you are not a fully qualified electrician.

The Government introduced a law in January 2005 which demands that most electrical work in UK households is only carried out by a ‘competent person’. This law means that Electrical safety requirements have been included in a new Part P of the Building Regulations.

Part P Explained

The law states that anyone carrying out fixed electrical installations in households in England and Wales must ensure that electrical installations are:

  • Designed and installed to afford appropriate protection against mechanical and thermal damage, and so that they do not present electric shock and fire hazards to people.
  • Suitably inspected and tested to verify that they meet the relevant equipment and installation standards.

It is against the law to have a new circuit installed in your home without having it inspected and tested to ensure that it is Part P compliant. This can be achieved in two ways:

  1. Appoint an electrical contractor who is registered with a competent person scheme. If you are unsure about who is Part P qualified visit the websites of the following organisations who all run Part P registration schemes to ensure your contractor is registered with one of them.

  2. Appoint someone who is not Part P registered but contact your local authority’s Building Control Department first. The work will have to be inspected and tested by your local authority before it can be signed off. There will be a charge for this service.

Either way you will receive a Part P certificate after the Hot Tub electrical supply work is completed. From post 2007 these will need to be kept on file and presented if you even sell your house as part of the Home Seller’s Packs.

Your Hot Tub retailer can liaise with your electrical contractor regarding the exact specification for your Hot Tub but you must meet the following specification:

  • The Hot Tub must be hard wired on its own fused spur back to your household consumer unit (i.e. the Hot Tub should not be sharing a supply with any other appliances).

The Hot Tub should be protected by a sufficiently rated MCB (mains circuit breaker) and should cover the maximum amperage pull of the Spa plus 25% to allow for brake torque (i.e. the extra rush of current when pumps are first started). Therefore a Hot Tub that has a maximum current draw of 20 amps should be fitted with a 25amp MCB.

The Hot Tub should also be protected against earth faults by an RCD (Residual Current Device). This is a trip switch with prevents danger of electric shock from damaged or waterlogged cables and connections. A suitable rated 30mA RCD is recommended.

Outdoor cabling should be protected from damage by either laying protective ducting (pc pipe) below ground or by using Steel Wired Armoured (SWA) cable. Your electrician will calculate the size of cable required depending on the loading and the distance from the mains supply.

Waterproof Outdoo Plug Socket

13 AMP Electrical Requirements

The electrical requirements for the 13AMP plug-and-play Hot Tubs are the simplest to complete. The 13AMP Hot Tubs simply plug into a standard domestic power supply so all you need for the 13AMP Hot Tubs is an outdoor waterproof plug socket with RCD protection.

32 AMP and 40 AMP Electrical Requirements

6mm² 3-core SWA cable is needed for a 32AMP Hot Tub and a 10mm² 3-core SWA cable is perfectly suitable for a 40 AMP Hot Tub.

IP65 45amp Rotary Switch

An IP65 45AMP Rotary Isolator Switch is also recommended so that the Hot Tub can be isolated outdoors in an emergency or for service work. This is simply a rotary on/off switch but should be sited more than 2 metres away from the Hot Tub so that bathers cannot be in the Hot Tub whilst touching the switch.

The electrician should fit a suitable weather proof block connector to the end of the tail from the isolator, the Hot Tub supply can then be directly hard wired into the weatherproof block connector inside the Hot Tub. Waterproof gland packs should be used to prevent ingress of water on all electrical connections (2 at the isolation switch). Ensure that all earth cables are clearly colour coded with green/yellow insulating tape or earth sleeve.

Once the Hot Tub is filled with water and the electrical supply is installed your Hot Tub installation team should commission the Hot Tub and check that everything is fully operational before ‘handing over’ to you with a complete chemical training guide and Hot Tub features.

If you are in any doubt about the required electrical guidelines you should seek professional advice from a fully qualified electrician.

Please note: your electrician should leave enough spare cable attached to the isolator to go to the farthest side of the Hot Tub. Our technicians are qualified to connect this cable to the inside of the Hot Tub.