When choosing a hot tub, it is important to think about more than its size, seating and hydrotherapy. You also need to consider how it will be powered.
Hot tubs sold in the UK can have very different electrical requirements. Smaller models may operate from a 13 amp supply, while larger premium hot tubs typically require a dedicated 32 amp, 40 amp or higher electrical supply.
Whichever hot tub you choose, the electrical installation needs to be suitable for the individual model and comply with current UK electrical regulations.
Hot Tub Electrical Safety in the UK
Water and electricity require particular care, which is why the electrical installation for a hot tub should always be properly assessed.
Electrical installations must comply with BS 7671, the IET Wiring Regulations. For an outdoor hot tub, the risks are increased because users are wet, body resistance is reduced and there may be direct barefoot contact with the ground.
The electrical installation therefore needs to consider several important areas, including:
- RCD protection
- Correct earthing arrangements
- Cable type and size
- Electrical load and amperage
- Safe isolation
- The position of electrical equipment around the hot tub
- The existing electrical installation at the property
For this reason, we always recommend having the electrical work completed by a suitably qualified electrician.
13 Amp Plug and Play Hot Tubs
Some smaller hot tubs can operate from a 13 amp electrical supply. These are commonly referred to as Plug and Play hot tubs because they do not require the same high amperage dedicated supply as larger models. This can make them a convenient option where simplicity of installation is important.However, there is a trade off.
With the available power limited to 13 amps, the hot tub may not be able to operate its heater and high speed massage pumps simultaneously.
For example, when the jets are running at full power, the heater may temporarily switch off. Once demand from the pumps reduces, the heater can operate again. This is perfectly normal for a hot tub designed to work this way, but it is worth understanding when comparing a 13 amp model with a larger hard wired hot tub.
Does a 13 amp hot tub need RCD protection?
Yes. Appropriate RCD protection is an important part of protecting users against electric shock.
Even if a hot tub is designed to connect to a socket rather than a dedicated 32 amp circuit, this does not mean electrical safety requirements can be overlooked. The socket, circuit and RCD arrangement should be suitable for the hot tub and its location.
32 Amp Hot Tubs
Many larger hot tubs require a dedicated 32 amp electrical supply. Rather than simply plugging the hot tub into a socket, the electrician installs a dedicated circuit from the property's electrical installation specifically for the hot tub. One of the main advantages of the additional electrical capacity is that the hot tub can support more powerful equipment.
Depending on the model, this can allow the heater and massage pumps to operate simultaneously, helping the hot tub maintain its water temperature while the hydrotherapy system is being used. This is particularly useful for larger hot tubs with multiple pumps and more powerful jet systems.
40 Amp and Higher Electrical Supplies
Some premium hot tubs have even greater electrical requirements and may require a 40 amp or higher supply. The exact requirement depends on the model, its heater, the number and size of its pumps and how its control system is configured. This is why we recommend choosing your hot tub before having the final electrical supply installed.
A hot tub should never be assumed to require 13, 32 or 40 amps simply because another model of a similar size does. At Take Wellness, we can provide the electrical requirements for your chosen model so that this information can be passed directly to your electrician.
What Is a Hot Tub Isolator?
Hard wired hot tubs normally require a suitable local isolation point. This allows the electrical supply to the hot tub to be safely switched off when required for servicing, maintenance or an emergency. For an outdoor installation, the equipment also needs to be suitable for the environment and correctly positioned in relation to the hot tub.
The IET recommends fixed wiring for hot tubs where appropriate and advises that the isolator is positioned outside the immediate zone surrounding the water. Your electrician will determine the correct position for your particular installation.
Earthing a Hot Tub
Earthing is another particularly important consideration with an outdoor hot tub. An electrician needs to assess the earthing arrangement at the property and determine the appropriate solution for the installation. This is important because users will typically be wet and barefoot when entering and leaving the hot tub.
Depending on the existing electrical supply and installation design, additional measures such as an earth electrode may need to be considered. There is no single earthing solution that should simply be applied to every hot tub installation. It needs to be assessed by the electrician based on the property, hot tub and surrounding environment.
What Cable Is Used for a Hot Tub?
The cable required depends on several factors, including:
- The amperage of the hot tub
- Distance from the consumer unit
- Cable route
- Installation method
- Voltage drop
- Environmental conditions
For external and underground cable runs, Steel Wire Armoured cable, commonly known as SWA, is frequently used because of the mechanical protection it provides.
Where cables are buried, they need to be protected against foreseeable damage and installed at an appropriate depth and using an appropriate method.
As a general installation guide, underground SWA runs are commonly installed at around 500mm depth, increasing to around 600mm in areas subject to vehicle traffic, although the electrician must determine the correct installation method for the individual site.
13 Amp vs 32 Amp vs 40 Amp Hot Tubs
The easiest way to understand the difference is:
13 Amp
Usually found on smaller Plug and Play hot tubs. Installation can be simpler, but available power is limited and the heater and high speed pumps may not be able to operate simultaneously.
32 Amp
Common on larger and premium hot tubs. Requires a dedicated electrical circuit and provides greater capacity for heaters, pumps and hydrotherapy equipment.
40 Amp and above
Used by some larger or more powerful hot tubs where additional electrical capacity is required. A dedicated circuit and professional installation will be required.
Can I Have the Electrics Installed Before Choosing My Hot Tub?
We recommend choosing the hot tub first.
Although installing a 32 amp supply in advance might seem sensible, your eventual hot tub could require a different supply or configuration.
The distance from the consumer unit, cable route and electrical requirements of the model can all affect how the installation needs to be designed.
Choosing your hot tub first means we can give you the correct electrical specification to pass to your electrician.
What Should I Tell My Electrician?
Once you have selected your hot tub, Take Wellness can provide the electrical requirements for that particular model.
Your electrician can then assess your property and determine the appropriate:
- Circuit
- Cable size
- RCD protection
- Earthing arrangement
- Isolation
- Cable route
- Connection point
This avoids guesswork and helps ensure everything is ready before your hot tub arrives.
Preparing for Your Hot Tub Installation
Electrical preparation is one of the most important parts of getting ready for a new hot tub, but it does not need to be complicated.
The main thing to remember is that different hot tubs have different electrical requirements.
A compact 13 amp hot tub and a premium 40 amp model may offer very different experiences and require very different electrical installations.
Choose your hot tub first, speak to the Take Wellness team about its requirements and provide the specification to your electrician.
That way, when delivery day arrives, the correct electrical supply can already be in place and ready for your new hot tub.
Need Help?
If you are considering a hot tub from Take Wellness, speak to our team about the model you are interested in.
We can explain whether it requires a 13 amp, 32 amp, 40 amp or alternative supply and provide the relevant electrical information for your electrician before installation.