Project Guide

How to Wire a Hot Tub

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Turn off the Power at the Breaker Box
An illustration shows a person turning off the power at a breaker box.

As with all electrical projects, follow local codes and consult an electrician before wiring a hot tub. In addition, you must have the wiring inspected before using your hot tub. 

Begin by turning off the power to your home at the main breaker box

Safety: Electricity and water are a dangerous combination, so do not fill the hot tub until it is wired and inspected. Most electrical codes require hot tubs to be at least 10 feet from overhead power lines. 

Mount the Spa Panel
An illustration shows a spa panel mounted on a wall.
  • As a manual disconnect device, the spa panel solves the problem of false tripping that occurs if the hot tub is wired directly to a two-pole GFCI breaker. 
  • Follow the instructions included with your spa panel and mount it on the wall of your house, no closer than 5 feet from the spa location, but in line of sight of the spa. This distance is partly to reduce the chance of someone touching the panel with one foot in the hot tub. 

Tip: Before installing a hot tub, confirm that your home’s electrical service can handle the additional load. 

Dig the Conduit Trench
An illustration shows a conduit trench that meets a wall below a spa panel.
  • Consult your local building code to determine the depth for laying the conduit and contact your local utility companies to ensure you don’t cut into a buried utility cable or pipe. Some conduit trenches can be 18 inches deep.
  • Carefully remove the sod, if you have it, cutting it into manageable squares and setting it beside the trench. 
  • Using a shovel, dig the trench for your conduit to run from the electrical breaker panel to the spa panel and from the spa panel to the spa. 
  • Do not run wire or the conduit under the hot tub.  
Run the Conduit
An illustration shows conduit running from a spa panel to a trench.
  • Use a hole saw to drill a hole through the outside wall near the breaker panel for the conduit to exit the house. 
  • Measure, cut and cement the necessary conduit and fittings to run from the breaker panel down the wall, across the trench to the spa panel, and from the spa panel down to the trench and across to the spa. 
  • If the run is under 6 feet, use liquid-tight flexible metal or non-metallic conduit in lengths of no more than six feet. For longer runs underground, use rigid metal conduit, intermediate metal conduit or a non-metallic system listed for direct burial. PVC is a popular conduit material.
  • Insert an LB fitting in the hole in the wall to connect the indoor and outdoor conduit. 
  • Use “sweep” fittings (which make gentle curves rather than sharp 90-degree curves) whenever possible to make pulling the wires easier. 
  • Do not bury the conduit until after you have the wiring inspected. 
Pull the Wires
An illustration shows a person pulling wires into a spa panel.
  • During hot tub wiring, copper wire is recommended with THHN (thermoplastic nylon) insulation. Avoid aluminum wire. The recommended hot tub wire size is 6 AWG copper.
  • Beginning at the LB fitting, use fish tape to pull the wires from the fitting to the spa panel. 
  • Leave at least 6 inches of extra wire hanging from the spa panel. 
  • Push the wires through the LB fitting into the house and to the breaker panel, leaving at least 6 inches of extra wire hanging. 
  • Use fish tape to pull the wire through the conduit from the spa panel to the control panel on the spa. Leave at least 6 inches of extra wiring on either end. You may opt to cut a hole in the spa’s toe kick for the conduit.

Tip: You may want to have another person available help pull or push the wires.  

Wire the Spa Panel
An illustration shows a person wiring a spa panel.
  • Be sure to follow your spa panel and spa instructions when wiring the panel. 
  • First, attach the wires that lead to the spa. Attach the red, white and black wires to the bottom of the GFCI breaker, and attach the green grounding wire to the ground bar. 
  • Attach the wires from the breaker panel, and attach the black and red wires to the breaker feed lugs on top of the breaker. Attach the white wire to the line neutral bar. Attach the green grounding wire to the ground bar. 
Wire the Spa Control Panel
An illustration shows a person wiring a hot tub control panel.

Wire your spa’s control panel per the manufacturer’s instructions.

Wire the Spa Panel to the Breaker Panel
An illustration shows a person wiring a spa panel to a breaker panel.
  • Confirm the main breaker is off and no power is present. 
  • Be aware that even with the main breaker off, the wires coming from the power company are still energized. Be careful when working in the breaker box. 
  • Attach the red and black wires to a dedicated double-pole 240V GFCI circuit breaker. 
  • Label the new spa circuit breaker.  
Have the Spa Inspected
An illustration shows an empty hot tub.
  • Before energizing or filling your hot tub, call the electrical inspector to schedule your wiring inspection. 
  • Once your hot tub wiring has passed inspection, bury the conduit and replace sod over the trench as needed.
  • Fill your hot tub with water and enjoy. 

Hot tub wiring requires familiarity with local codes and electrical equipment, so consider hiring a licensed electrician. The most complex aspect of hot tub installation, knowing how to wire a hot tub, is essential for enjoying an outdoor spa day.