Hot Tub Wiring

Hot Tub Wiring

Electrical wiring and water are a potentially lethal combination and yet hot tubs are considered safe. So just how do you wire a hot tub to avoid the risk of electrocution?

The installation process for most hot tubs is largely centered around the electrical wiring. Both the National Electrical Code and local authorities provide regulations that are relevant to hot tub installation, so owners need to make sure they adhere to these.

Even a licensed electrician is not infallible so, before you get a hot tub installed, check the following guide for key information about how it should be wired to ensure safety and regulatory compliance.

Hot Tub Wiring

There are two main types of hot tub when it comes to electrical installation, plug-and-play and hard-wired. Plug-and-play hot tubs have a much simpler installation process but do not tend to have as high a level of specification, especially in terms of heating and pump power, number of jets, etc. as their hard-wired counterparts. Both are explained below.

Hard-Wired Hot Tubs

Most modern hot tubs need to be hard-wired into the mains electrical supply via a dedicated line from the main load center. This is because they draw a higher voltage (220/240V) than the household appliances you run in your home (120V).

Because of the high power drawn by hot tubs, their installation is subject to various regulations under the National Electrical Code and local building codes. 

Hard-Wired Hot Tubs

You need to understand these before attempting to install and wire a hot tub. If you aren't a licensed electrician, you shouldn't attempt to carry out the electrical portion of your hot tub installation. However, you should still be aware of the relevant national and local codes so you can ensure they are being followed.

If you need an electrician who can wire your hot tub at your home, look no further. Just fill out the form below and you'll receive competitive, personalized quotes from reliable and experienced professionals in your area.

Hot Tub Placement

Even before you consider how to wire a hot tub outdoors, you need to be aware of some rules regarding the placement of outdoor electrical equipment. A hot tub is not allowed to be placed within 6' of any unbonded metal objects, and 6' from any lighting or other electrical equipment.

There are even specific rules for overhead power lines, stating the hot tub must be at least 22'6" from the nearest overhead cable.

Ground Fault Circuit Interrupter

Ground Fault Circuit Interrupter

A Ground Fault Circuit Interrupter (GFCI) is a specific kind of circuit breaker designed to interrupt the current very quickly (within 1/40 of a second) if there is a failure of the grounding system.

It's essential to run any hot tub on a GFCI protected circuit (50-60A, depending on the relevant information in the hot tub owner's manual), as the GFCI breaker is one of the main measures preventing electrocution if water gets into any of the electrics in the spa cabinet.

Many modern hot tubs are sold with a GFCI breaker pre-installed. However, if you are buying an older model or one without an inbuilt GFCI you will need to get one installed to meet the relevant building codes (both NEC and local codes).

Disconnect Box

An electrical disconnect box is a device designed to isolate a circuit from the electric feed. These can have manual switches for maintenance purposes as well as fused circuit breakers for surge protection.

A hard-wired 220/240V hot tub should have its own disconnect box separate from the circuit breaker box for the property. One reason for it being separate from the main house panel is that it needs to be between 5ft-15ft from the hot tub. Especially if you are placing your hot tub outdoors, the central breaker panel is unlikely to be close enough for hot tub users to have quick access.

Power cables

Due to the high load, there are specific recommendations for the wire size and type used to supply power to the hot tub's electric panel. Copper wire of at least 6-AWG is recommended, as thinner wires can overheat and create a fire hazard.

It is also important to avoid using aluminum to wire a hot tub. This is partly because of how much the aluminum expands under heat, which can break connections and create a hazard. Older types of aluminum wire can also start a fire even at loads that won't trip a breaker.


Whether using overground or underground wiring, a suitable conduit pipe is essential to prevent damage to the cables and associated dangers. Direct burial of the cables leaves them susceptible to various environmental factors which cause swift degradation.

Before you wire a hot tub, make sure you check the local building codes concerning conduit materials, trench depths for underground wiring, etc. 


As a rule, you should not use an intermediate metal conduit if your ground wire is over 6' in length. Although these steel pipes may look like a good option, it is best to avoid unshielded metal if passing your ground wire over a longer distance between the spa panel and GFCI.

A PVC conduit is generally preferable for this reason. If you need a flex conduit due to the route being taken, a jacketed metallic type may work best. This consists of a liquid-tight flexible metal core surrounded by a thermoplastic nylon jacket to provide extra insulation.

Whatever sort of conduit you use, you will need to feed the wire through it carefully. The easiest method for pulling wire is to use a fish tape. The fish tape is a tool with a spool around which is wound 25' (or more) of flat metal tape. this can be dropped through a conduit and used to draw the wire back through, regardless of whether you are using a flex conduit or a rigid PVC conduit.

How to Wire a Hot Tub

How to Wire a Hot Tub

Hot tubs use a standard wiring system with two live wires (one black, one red), a white neutral wire, and a green ground wire.

If you are suitably qualified and experienced to wire a hot tub yourself, the following steps should be followed in order to minimize risks and ensure the correct functioning of the hot tub.

  1. Ensure the power supply is switched off using an approved manual disconnect device.
  2. Connect both live (red and black) wires to the circuit breaker in the service panel.
  3. Connect the neutral wire and ground wire to the grounding bus bar (neutral bar).
  4. Run the wire to your GFCI breaker box, using a suitable conduit pipe.
  5. Attach the black wire to the "Line in 1" connection in the GFCI box. The red wire connects to "Line in 2".
  6. Attach the neutral wire to the neutral bar in the GFCI box, and the ground wire to the grounding bus bar.
  7. Inspect all connections and make sure they are secure and in the correct order before reconnecting the power supply to the hot tub panel.

Before conducting any work involving the electrical connections, ensure you check the hot tub owner's manual. Again, it is strongly recommended that you do not attempt to wire a hot tub service panel unless you are a licensed electrician.

Before conducting any work involving the electrical connections, ensure you check the hot tub owner's manual. Again, it is strongly recommended that you do not attempt to wire a hot tub service panel unless you are a licensed electrician.

If you are looking for someone to conduct the electrical installation of your hot tub for you, fill out the form below. Licensed professionals with experience in wiring hot tubs will send you quotes.

Plug-and-Play Hot Tubs

Plug-and-play hot tubs are so-called because they use a standard 110/120V plug and can be run off a nearby wall socket using the normal household electricity supply. These do not require specialist installation but there are still some rules you need to follow.

Firstly, the outlet into which you plug the hot tub must not be running any other devices. A dedicated outlet is important due to the relatively high load drawn by a hot tub. 

Plug-and-Play Hot Tubs

If you try to run extra devices you risk either your hot tub not working properly, or blowing a fuse/trip switch in your home's main breaker panel.

It is also important to check whether your hot tub has an in-built GFCI circuit breaker box. If a GFCI is not included at the point of manufacture, you should ask an electrician to install one on the circuit you will use to power the hot tub.

Final Thoughts - Should You Install Your Own Hot Tub?

Given the inherent hazards when you wire a hot tub or other high-powered appliance, carrying out your own hot tub installation really isn't a good idea. Much better to have the peace of mind that comes with having a licensed electrician come and do your hot tub wiring for you.

Any professional electrician should know all of the relevant sections of the National Electrical Code, as well as any specific local codes which might affect how they wire a hot tub. 

They also have all the right tools and are likely to be buying the relevant components wholesale (GFCI breaker, cables, PVC or flex conduit pipe, etc.), so you may not even save very much by taking the risk of trying to wire a hot tub yourself.

We can help you source the right people for the job. The form below allows us to pass on your details and requirements to the best professionals in your local area, so they can send you their lowest quotes for fully National Electrical Code compliant hot tub installation.


About The Author

Meredith Kiley

Full-time staff writer at and stay-at-home mom.