If your hot tub stops heating, you might have a wiring problem. You may be able to fix this if you're comfortable with electrical wiring, but if you're not, you should hire a professional—dealing with electricity and water at the same time is a hazardous combination. Hot tub wiring is not that complicated to understand, but if you're in doubt, it's safer to leave it to the experts. This way, you will not be in danger of electrocuting yourself nor short-circuit your wiring system. Safety should always be your first concern when dealing with water and electrical wiring.
Step 1 - Consult a Local Inspector
Consult with your local building inspector. New hot tubs should be up to code. Your municipality might need a licensed electrician to wire your tub, but sometimes only a permit is needed, or perhaps someone should inspect it first before starting the project.
Step 2 - Check Service Panel
Check your service panel to see if it has sufficient capacity for the amperage requirement and open slots to accommodate your hot tub power requirements. Also, check your hot tub for the electrical connection panel, typically located at the back cover bolted outside the hot tub unit.
Step 3 - Run Wiring
Run wiring to the hot tub from the service panel. It is important to run these wires through a PVC or metal conduit. If the wires have to run inside the home, they can run through the basement or crawl space. If outside the home, the wire should be buried underground, especially if the tub is more than a couple of feet away from the house. To know the owner's manual will indicate the number of wires and gauge of wire in the owner’s manual of your new hot tub.
Step 4 - Check the Slots
Check for the required two adjacent slots in the service panel and for the installation of the double pole breaker. The red and black wires, which are hot, will connect to the breaker and the ground, while the neutral wires should connect to the ground bar.
Step 5 - Check the Line
Ensure the line from the service panel will connect to the “line in” connections indicated on the disconnect box. Another line will connect the “line out” connection going towards the hot tub. Depending on your hot tub model and make, the manual will provide a wiring diagram on how to wire your disconnect box.
Step 6 - Check the Control Panel
Look at the hot tub control panel. The hot wire and neutral wire will connect to the designated posts, and the ground, which is typically green in color, will wire a connection to the grounding connection. Again, check the installation guide of your hot tub so you can identify the proper connections and where each wire should go.
Step 7 - Recheck Connections
Double-check all connections. Before turning on the power of your tub, have your work inspected by a licensed electrician or building inspector. Never power your hot tub until it is carefully and properly inspected.