Having a hot tub in your house allows you to luxuriously relax in the comfort of your own home. Some hot tubs allow for voltage conversion, which lets you plug in the tub regardless of the electric current running to the location where your hot tub is installed. However, not all hot tubs are built or equipped with this unique feature, so always consult your owner's manual or the manufacturer before attempting such a conversion.
Disconnect all power to the hot tub. If the hot tub is a plug-and-play type, simply unplug the cord from the outlet. On the other hand, accessing the ground fault circuit interrupter or GFCI can be safer because it disconnects permanently connected wires. Remember to disconnect electric power to the GFCI before accessing it and always check the outlet using a voltage or meter indicator before disconnecting the wires.
Locate the heater connections. Check the hot tub's manual when locating the heater connections panel. This is typically located at the bottom or the side of hot tubs. You might have to loosen some screws to open the panel. You know that it's the right panel if it has wiring connections inside.
Familiarize yourself with the electrical wiring. A 240V-powered hot tub will commonly have four active wires. These wires include the hot wires, also referred to as line 1 and line 2, and the ground and neutral wires. These wires are sometimes color-coded or are labeled accordingly. Usual color codes are green for ground, white for neutral, red for line 1 and black for line 2. Some 240V hot tubs have three wires—line 1, line 2 and the ground.
Disconnect and reconnect the wires. For maximum safety, hire a qualified and licensed electrician to do this. For a 120V tub, only lines 1, neutral and ground are active. Thus, to convert the tub from 240V to 120V, unscrew line 1 and neutral wire from their respective posts. Then, attach line 1 to the post vacated by unscrewing of neutral wire. Keep the neutral wire disconnected.
Reattach the panel cover and then reconnect the hot tub to power source. Again, prioritize safety by checking the wires with a tester before touching them.