How to Wire a Hot Tub

The electrical tools you will need to wire a hot tub are:

• Voltage tester
• Set of screwdrivers
• Wire stripers
• Side cutters
• Drill
• Hole saw kit
• Fish tape
• Electrical tape
• If using PVC Conduit, a PVC cutter
• Hacksaw for all rigid metal conduit

Before you begin, shut off the power to your home from the main breaker box. As with all electrical projects, follow local codes and consult an electrician before wiring a hot tub.

The National Electrical Code (NEC) requires:

• Hard-wiring the spa into a ground fault circuit interrupter (GFCI)-protected 220 to 240V, 50 or 60 amp dedicated circuit.
• Installing a manual disconnect device, often called a spa panel, between your home’s electrical breaker panel and the spa.
• All receptacles must be a minimum of 6 feet away from the inside wall of the hot tub and GFCI protected.
• Have the wiring professionally inspected before using your hot tub.

Safety Tip: Electricity and water are a dangerous combination. Most electrical codes require hot tubs to be at least 10 feet from overhead power lines.

The spa panel is a manual disconnect device that will prevent false tripping, which can happen when a hot tub is wired directly to a two-pole GFCI breaker.

Mount the spa panel to the wall of your house according to the manufacturer's instructions. The panel should be located in sight of your hot tub but positioned at least five feet away. This distance reduces the potential hazard of someone touching the panel while making contact with the water in the hot tub.

Tip: Before you wire your hot tub, confirm that your home's electrical system is capable of handling the additional load demands.

Install the conduit in a trench. Conduit is a long tube of metal or PVC that will hold the electrical wires. Consult your local building code to determine how deep to lay the conduit. Some conduit trenches must be as deep as 18 inches.

Use a shovel to dig the conduit trench. Carefully remove the sod from the trench location. If necessary, cut it into manageable squares, and set it aside. The trench should extend from the spa panel to the spa and from the spa panel to the electrical breaker panel. Do not bury conduit underneath the hot tub.

The conduit will exit the house near the breaker panel, so use a hole saw to create an opening through the outside wall. Then, measure, cut and cement the conduit and fittings. Your measurements and cuts should cover the distance down the wall from the breaker panel, across the trench and up to the spa panel, then down from the spa panel and across the trench to the spa.

If the underground run is shorter than six feet, you can use a conduit made of liquid-tight flexible metal or a non-metallic material. Conduit sections longer than six feet should be made of rigid metal, intermediate metal, or rigid, non-metallic materials listed for direct burial. PVC is a popular option.

Connect the indoor and outdoor conduits by inserting an LB fitting through the hole in the exterior wall. Next, run the wire.

• Use "sweep" fittings where possible to make pulling wires easier, since they have gentle curves rather than sharp, 90-degree angles.
• Avoid using aluminum for hot tub wiring. Instead, use size 6 AWG copper wire with THHN (thermoplastic nylon) insulation.
• Use fish tape to pull the wires through the conduit from the fitting to the spa panel.
• As you pull the wires through the conduit, leave 6 inches of extra wire hanging from all ends. Start wiring at the LB fitting, and use fish tape to pull the wires through to the spa panel.
• Push the wires from the LB fitting into the house and to the breaker panel. Finally, use fish tape again to pull the wire through the conduit running from the spa panel to the control panel on the spa. If you wish, cut a hole for the conduit in the hot tub's toe kick.

Tip: Before you dig, contact your local utility company to mark your utilities and ensure you don't cut into any buried lines, pipes or cables.

Before you start attaching the wires, consult the manuals for the hot tub and spa panel and follow the instructions for your specific units. Double check that the main breaker is off. Even when the main breaker is off, it is important to exercise caution, since the power company’s wires will still be electrified.

• Hook up the wires that lead to the spa. The red, white and black wires attach to the bottom of the GFCI breaker, while the green grounding wire attaches to the ground bar.
• Hook up the wires that lead to the breaker panel. The black and red wires attach to the breaker’s feed lugs along the top, and the white wire attaches to the neutral bar. The green grounding wire attaches to the grounding bar.
• The green ground wire and the white wire need to be connected as indicated and must not be connected on the same ground bar or neutral bar.
• Make sure you only put one wire under the terminals in the panel. If the panel is the main service disconnect, as it may be in older homes, then the neutral bar and the ground bar may be connected together. At that point the white wire and the green wire will be connected on the same bar, but still with only one wire under each terminal.
• Wire your control panel. Follow the manufacturer's instructions to correctly wire the control panel on the spa.
• Wire your breaker panel. Attach the black and red wires from the spa panel to a dedicated, double-pole 240V GFCI circuit breaker. When you’re finished, take the time to clearly label the new spa circuit breaker.

When you’re finished wiring a hot tub, consult with an electrician to ensure that the installation follows all local safety codes. A certified electrician must also inspect your hot tub wiring before you use it for the first time.

Once everything has been checked and approved, bury the conduit in the trench, cover it with dirt and replace any sod you had to remove.