Hot Tub Electrical Requirements

Most hot tubs require a 220-volt, 50-amp circuit to operate the heater, pumps, lights, and ozonator system. Check the owner's manual for the exact specifications and requirements for your unit. Wiring for hot tub spas should only be done by a qualified individual. Serious injury or death could result from improper wiring. Consult with a building inspector for details and requirements for your area.

Main Service Panel

Tending to a hot tub electrical system requires expertise.

Sufficient capacity is needed at the main panel. Most homes are equipped with 100- to 200-amp service panels. A qualified electrician should be consulted to determine whether an additional load can be accommodated with the current electrical draw. Most models of hot tubs require 240 volts at 50 amps to run the heat and pump systems. They also require two spaces in the panel for a double pole, 240-volt circuit breaker.

GFCI Weatherproof Box and Circuit Breaker

A quick disconnect ground fault circuit interrupter (GFCI box) needs to be installed within 5 feet of the spa. This box should be within line of site of a spa user. A GFCI is a circuit that monitors electricity flow in a circuit. If there is a difference or change in the flow, even a slight change, the GFCI quickly terminates power.


A trench should be dug for the electrical cable and conduit to be placed in if the spa is installed away from the house. Follow building codes to determine the required depth. A trench more than 18 inches deep is required in most areas. Metal caution tape should be placed 12 inches above the cable. In case of future excavating in the area, it will give warning of an electrical cable near by. The trench should be open for final electrical inspection and testing before covering.

Conduit and Wire

Electrical conduit is needed in the trench from the outdoor disconnect box to the spa. A string is pulled through the conduit or an electrical fish tape is used to pull the wire through. The wire is tied securely to the tape or string and pulled through, leaving about 12 inches on each end for termination. A No. 4 stranded copper wire is normally used for most hot tubs. It has a capacity of more than 60 amps. If using an aluminum wire, usually one size larger is used to carry the capacity of the circuit. Antioxidant compound is used on the ends when installing with aluminum wire.

Continue Reading