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Hot weather Hot tubs.

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’. The law means that Electrical safety requirements have been included in a new Part P of the Building Regulations. Hot tub installations must also comply with section 702 in the 17th Edition IEE (Institute of Electrical Engineers) Regulations as they fall in the same category as swimming pools.

This guide sets out everything you need to know for setting up an electrical connection for a hot tub including details on Part P and how to find a qualified electrician.

What is Part P?

Who is responsible for ensuring electrical work meets Part P requirements? How do I ensure Part P requirements are met?

How many amps do you need for a hot tub?

What are the electrical requirements for a hot tub?

Part P explained

What is Part P?

Part P is a section of the Building Regulations that covers England and Wales (Scotland is covered by the Building Standards system) and was introduced to reduce the risk of personal injury or damage to a home due to poor workmanship.

Part P applies to anyone carrying out fixed electrical installations in households and states:

“reasonable provision shall be made in the design and installation of electrical installations in order to protect persons operating, maintaining or altering the installations from fire or injury”

Who is responsible for ensuring electrical work meets Part P requirements?

It is the responsibility of the homeowner to prove that any electrical work carried out meets Part P requirements and it is a criminal offence if it does not.

To comply with Part P, all electrical work must follow the rules set out in BS 7671.

How do I ensure Part P requirements are met?

There are 3 options when contracting an electrician to install your hot tub which are detailed below:

Contract a Part P qualified and registered electrician which can be found through one of the following schemes:




Your electrician can employ a qualified and registered electrician to inspect their work which also removes the requirement for a local authority inspection

A fully qualified but unregistered electrician can inspect their own work or can employ a qualified electrician to carry out an inspection

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

Electrical installation

How many amps do you need for a hot tub?

Most hot tubs require at least a 13AMP supply with larger hot tubs requiring a 32AMP supply. We can liaise with your electrical contractor regarding the exact specification for your Hot Tub, alternatively more details can be found within the technical specifications on our hot tubs pages.

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. We will provide up to 5 metres of cable and a plug to plug into the socket you have provided.

32 & 40 AMP electrical requirements

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

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.

What are the electrical requirements for a hot tub?

The electrical installation must comply with BS:7671 – “Requirements for Electrical Installations IET Wiring Regulations”, particularly concerning the following specifications:

The hot tub must be hard wired on its own fused spur back to your household consumer unit, not 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 be protected against earth faults by an RCD (Residual Current Device). This is a trip switch which prevents the possibility of an 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

Once the hot tub is filled with water and the electrical supply is installed your 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.

Post comments: 3

  • Sarah


    July 1, 2018 at 9:20 pm

    It’s very easy to forget that a hot tub, as with any heated swimming pool, will require the mix of water and electrical systems in order to operate properly, and this can pose a massive risk if not installed properly. It can be all too easy to impulse-buy a hot tub online and then not want to fork out for a proper installation but this is not recommended – get a professional, and be safe rather than sorry.

  • do i need an electrical safety certificate to sell my house

    do i need an electrical safety certificate to sell my house

    March 9, 2019 at 7:35 am

    Your style is very unique in comparison to other folks I have read stuff
    from. I appreciate you for posting when you’ve got the opportunity,
    Guess I will just book mark this page.

    • Jeff Case

      Jeff Case

      March 9, 2019 at 8:01 am

      By law
      But you should

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