Wiring for Hot Tub Installation

Wiring a hot tub is challenging, but brings rewards.
Wiring a hot tub is challenging, but brings rewards. (Image: Ryan McVay/Digital Vision/Getty Images)

Relaxing in a hot tub helps ease the working day’s stresses. Once the tub is set up and plumbing completed, the wiring need installing. Most electric hot tubs operate on a 240-volt circuit. This type wiring is challenging for the electrical DIYer, but can be done as long as proper procedures and safety precautions are taken.

Things You'll Need

  • Ground Fault Circuit Interrupt panel box
  • Flat-head Screwdriver
  • Wire strippers
  • 4 wire electrical wires, 240 volt
  • Needle-nose pliers
  • PVC pipe, elbows, bends
  • PVC pipe cutters
  • PVC primer
  • PVC glue
  • Flexible hose
  • Hose clamps

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Install a Ground Fault Circuit Interrupt box for the hot tub. GFCI circuits measure the electrical output going through a circuit and automatically cut the power if they detect a voltage leak. This box can be mounted outside of the house or inside a covered structure such as an outbuilding. These boxes consist of an outside cover with a GFCI panel mounted inside. Mount the box on a wall and secure it with screws.

Run a line from the main circuit breaker out to the GFCI panel. In most setups, this will be a 240-volt line and require two circuits, a double pole, at the breaker. A qualified electrician must undertake this step in most municipalities. Before making the connection at the breaker, switch off the breakers where are making the connection to avoid electrocution. Connect one hot wire to each of the breakers. These wires are typically colored red and black representing live connections. Run a neutral, or white, wire from the neutral bar on the circuit breaker to the GFCI panel and a ground wire from the neutral bar as well.

Make the GFCI panel box connections. Connect the black wire to one side of the GFCI terminal. Strip the last one-half inch of wire with wire strippers. Squeeze the wire around the terminal screw with a pair of needle-nose pliers. Tighten the screw with a flat-head screwdriver to secure the wire. Connect the red wire to the terminal’s other side. Connect the white wire to the neutral bar and the ground wire to the ground bar.

Connect three wires from the GFCI box for the spa. Connect one red and one black wire to the GFCI terminal’s opposite ends from the same colored wires. Connect a ground wire to the ground bar in the GFCI box.

Run the wires to the spa location through a protective sheath. Use either rigid PVC or flex hose. When using PVC, measure the length of the needed run with measuring tape. Cut the PVC pipe to size with pipe cutters. Dry fit the PVC pieces together, using any elbows or bends as needed. Apply primer to the PVC pipe, and then glue the pieces together. Threading the electrical line through the pipe as you work makes it easier. Secure the pipe or hose to walls or eaves underneath the house with pipe clamps.

Make the connection at the spa with the red and black wires. Secure each wire to the spa’s electrical hookups. In most setups, one of the 120-volt connections controls the heating element, while the other controls the bubbles or jets.

Restore power at the main circuit breaker. Turn on the spa and check that the electrical connections are working properly. Before using the hot tub, test the GFCI circuit by hitting the "test" button while the hot tub is running. The tub should immediately switch off.

Tips & Warnings

  • Consult local electrical codes regarding hot-tub wiring before beginning construction. In some locations, this might need to be done by a certified professional.
  • Wiring for your specific hot tub may differ. Always follow the manufacturer's instructions.
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