Hot tub electrical installation guidelines

Having a hot tub installed?

Believe it or not, you could actually be committing a criminal offence if you make a misstep because you’re not clued up on the relevant Building Regulations.

In this short guide, we’ll walk you through everything you need to know about hot tub electrical installation guidelines, so there are no nasty shocks when your hot tub is getting wired up.

What is ‘Part P’?

Part P of the Building Regulations for England and Wales is the law you need to stick to when you’re installing a hot tub.

The Government introduced Part P in 2005 to ensure all home electrical installations are safe. These electrical safety rules state that all electrical work in UK households needs to be carried out by a ‘competent person’ – someone who’s fully-qualified to be doing the work.

This person is responsible for making sure electrical installations are designed and installed so they don’t become a hazard if they undergo mechanical or thermal damage. They’re also responsible for testing and inspecting the installation to make sure it meets the relevant equipment and installation standards.

Under Part P, it’s a legal requirement to have all the electrical wiring work for your hot tub done – or checked – by a fully qualified and Part P-registered electrician.

The only exception is if you buy a plug-and-play hot tub. Because these models can be plugged straight into a standard three-pronged socket, they don’t need to be installed by a professional – you just need to plug them in and switch them on.

What does ‘Part P’ mean for you?

By law, you need to be able to prove that all electrical installation work done to your home meets Part P or you’ll actually be committing a criminal offence.

If the authorities discover your hot tub installation isn’t up to the Building Regulations they can make you remove or alter it.

So, while making sure you meet Building Regulations isn’t exactly the most exciting part of owning a hot tub, it is important to get right.

Luckily, there’s not too much to it when you know what you’re looking for…

How to meet the ‘Part P’ requirements

The simplest way to make sure your hot tub installation meets Part P is to use a Part P-registered electrician. Any hot tub dealer worth their salt will know several sparkies that are registered as a ‘competent person’, so ask yours for a recommendation. These contractors will be able to self-certify their work as being compliant with Building Regulations, saving you a lot of hassle.

If you don’t go with a Part-P-registered contractor, you’ll either need to get a registered competent person or building control body to come out and check that the work meets regulations. As you can imagine, it’s a lot easier to just go with a Part-P-registered electrician in the first place.

If the contractors your dealership recommends aren’t available you can find a Part P-qualified and registered electrician through NICEIC, NAPIT, or ELECSA.

Be sure to arrange for your hot tub’s electrics to be installed before it’s delivered. Once they’re in, your electrician will flick the isolation switch to the ‘OFF’ position, coil up the SWA cable tail, and tape off the exposed wires at the end of the cable to keep water out until delivery day arrives. This will make it a piece of cake for your dealership’s installation team to wire up your spa.

Once your hot tub is installed, your electrician will issue you with a Part P certificate which you’ll need to keep on file, as all electrical works will need certification evidence if you decide to sell your home.

Hot tub electrical requirements

Hire a Part P-registered electrician to install your home spa and they’ll make sure the installation is up to spec.

Just so you know what to look out for, the electrical requirements your hot tub needs to meet are:

• The hot tub must be hard-wired on its own fused spur back to your household consumer unit – and not share a supply with any other appliances.
• The hot tub should be protected by a sufficiently rated MCB (mains circuit breaker). This should cover the maximum amperage pull of the spa plus 25 per cent to allow for brake torque (i.e. the extra rush of current when pumps are first started). That means a hot tub with 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 30mA RCD (residual current device). This is a trip switch that prevents damaged or waterlogged cables and connections from causing an electric shock.
• Your hot tub should be wired with SWA cable (6mm² 3-core SWA cable is suitable in most cases) or the cables you use from damage by feeding them through PVC piping. 
• You should also install a waterproof IP65 rotary isolation switch so your home spa can be isolated outdoors in an emergency or for service work. This should be installed at least two metres away from the hot tub so bathers can’t touch the switch while they’re in the water.
• A tail of SWA cable that’s long enough to be fed inside the spa cabinet and reach the load box within the hot tub equipment bay should be left from the isolation switch.

Wrapping up

Making sure you’re sticking to the hot tub electrical installation guidelines might seem daunting at first glance. But if you hire a fully qualified and Part P-registered electrician for the job – and make sure to file the certificate they give you away for if you ever sell your house – it should be plain sailing.
After more hot tub installation advice? Pick up your free copy of the latest edition of WhatSpa? magazine for plenty more – as well as our pick of the best buys for every budget.

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