You don’t need a permanent water supply for a hot tub or garden spa but you will need a suitable electrical supply to run the 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 hot tub electrics yourself if you are not a fully qualified electrician.

The Government introduced a new 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 now against the law to have a new circuit installed in your home without having it inspected and tested to ensure it is Part P compliant. This can be achieved in 2 ways

1. Appoint an electrical contractor who is registered with a competent person scheme. 

2. Appoint someone who is not Part P registered but contact you local authority 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 later in 2007 these will need to be kept on file and presented if you ever sell your house as part of the new home sellers packs.

We can liaise with your electrical contractor regarding the exact specification for your spa 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 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.)  A 32amp MCB should be fitted.

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

Outdoor cabling should be protected from damage by either laying protective ducting (pvc 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.  6mm 3-core SWA cable is perfectly suitable in most cases but always consult an electrician first.

An IP65 45amp Rotary Isolation 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 for the hot tub so that bathers cannot be in the spa whilst touching the switch.

The hot tub supply can then be  directly hard wired into the load box inside the spa.  Waterproof gland packs should be used to prevent ingress of water on all outdoor electrical connections (2 at the isolation switch and 1 inside the hot tub)  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 hottub and check that everything is fully operational before “handing over” to you with a thorough training of how all of the hot tub features work.