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What Size Wire for 50 Amp Hot Tub? Things to Know!

Written by Edwin Jones / Fact checked by Andrew Wright

what size wire for 50 amp hot tub

Hot tubs are a popular way to relax in the comfort of your home. But because they are powered by a lot of electricity and need water to do their job, installing these require fulfilling specific considerations.

Since these hot tubs can reach 50 amps of current, one thing to consider is what size wire for 50 amp hot tub. Generally, you’ll need individual 6 AWG copper wire for hot tub rated for wet or corrosive environments.

Common Wire Size for 50 Amp Hot Tub

We recommend using individual 6 gauge wire for 50 amp 220V hot tub installations. This ensures that the electrical connections to your hot tub will be safe (or at least, code-compliant).

Of course, not everyone needs a 50 amp hot tub. Here is a summary of other possible hot tub power requirements that you might encounter:

Hot tub capacity Voltage (volts) Current (amps) Wire size copper material
up to 5 people 120 15 12
up to 6 people 240


30 10
more than 6 people 50 6
60 4

Tips to Calculate 50 Amp Hot Tub Wire Size


A 6 gauge wire can safely handle up to 65 amps of current at 167⁰F. If we use the 80% rule, which says wires should not carry more than 80% of their rating, 80% of 65 is 52 amps, which is more than adequate to run our hot tub.

Going for thicker wires ensures that your cords will remain cooler when handling 50 amps and experience less risk of voltage drops too.

You can also consider future uses and upgrades. If you want to upgrade to a 60-amp hot tub in the future, then 4 gauge can be both the 50 amp and 60 amp hot tub wire size. 4 gauge wire can safely handle up to 85 amps, and again using the 80% rule, 80% of 85 is 68 amps, ample enough for your 60 amp hot tub.

Factors Affecting Wire Size

1. Wires should be at least approved for wet use, like individual THWN wires.


Remember that a hot tub will be considered a wet location, so your wires must be compliant with this. Your ground wire that connects to the tub must be insulated and must not be smaller than 12 gauge wire, as stated in the National Electric Code (NEC) 2023 Section 680.7.

Also, you must use wires approved for wet locations like THWN (the W means water-resistant).

This means you cannot use your usual Romex 6/3 or 6/4 wire for hot tub installations. Romex cables (also known as NM-B cables) are not intended for use in moist locations and only have paper sheaths (not insulation) for their ground cables.

2. Copper is the preferred wire material.


The use of aluminum wires is one of the common hot tub wiring mistakes. Honestly, most hot tub manufacturers would recommend the use of copper wires. The use of aluminum wires can even void the warranty of your hot tub.

Aluminum would need to be thicker (around 4 gauge) to meet the current carrying capacity of copper at 6 gauge size wire for hot tub. Also, aluminum expands and contracts too much and might eventually come loose on the lugs of the hot tub.

Lastly, aluminum may become more brittle and less conductive when exposed to moisture compared to copper.

3. Wattage

Multiply the voltage with the amperage of the hot tub to get its wattage. Then determine whether your wire size can handle that much power or not.

Can 50 Amp Hot Tub Use Other Wire Size?

Technically, you can go for an 8 gauge copper wire size for 50 amps 240 volts hot tubs since 8 gauge copper actually carries a maximum of 50 amps. Some manufacturers even allow 8 gauge wire for hot tub installation. But you might experience hotter wires which do have any allowance for possible voltage drops.

Of course, some might want to use a 4 gauge size wire for 220V hot tub, since it has a higher current carrying capacity than a 6 gauge wire. However, hot tubs might not have large enough lugs to fit 4 gauge wire. Always refer to the manufacturer’s manual.

Tips to Install 50 Amp Hot Tub

1. Conduits are part of the hot tub electrical requirements.

Because spas, pools, hot tubs and other similar environments can be considered corrosive, wires must be fed to approved conduits, according to NEC 2023 Section 680.14.

Thus, make sure that you provide the necessary conduit size requirements depending on how many 6 gauge wires you will use. You can use a conduit wire size calculator to help you estimate.

The NEC allows the following conduits for hot tub use:


  • Rigid metal conduit (RMC)
  • Intermediate metal conduit (IMC)
  • Rigid PVC conduit
  • Reinforced thermosetting resin conduit (RTRC)
  • Liquid tight flexible nonmetallic conduit (LFNC)

2. Check if you need a 3-wire or 4-wire setup for your hot tub.


Some 240 volt or 220 wiring for hot tub installations may have 3-wire setups (2 hot wires and one ground wire). These hot tubs only need 220 / 240 volts to run all of their features. However, some hot tubs will have a 4-wire setup (2 hot wires, 1 neutral wire, 1 ground wire) to have access to 110 / 120 volts for some features like an ozonator.

Always check your manual to see if you need a 3-wire or 4-wire setup. Do not try to fit a 4-wire model into a 3-wire setup, since it might damage the features that need 110 / 120 volts.

3. Check the requirements for the 50 amp hot tub disconnect switch and receptacles.

NEC Section 680.13 requires that hot tubs must have a maintenance disconnect that must be visible from the equipment and must be at least 5 feet (1.5 meters) away from the inner wall of the tub. Then, since hot tubs will need GFCI protection, the GFCI connected to the hot tub can be placed in the disconnect.

Also, NEC Section 680.22 (B) requires at least one GFCI-enabled 120 volt outlet 6 feet to 20 feet away from the inside wall of the hot tub. To sum all of this, here is a sample wiring diagram for a 4-wire hot tub:



If you are wondering what size wire for 50 amp hot tub you should use, you cannot go wrong with individual 6 gauge copper wires. This size is highly recommended by a lot of installers for a variety of reasons, ultimately leading to a functional and safely-working hot tub.

Just do not forget to let a qualified electrician or your supplier’s hot tub installer do the setup job. Hot tubs should not stress you out, so go out and have a hot tub installed for the ultimate home relaxation.


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