The three most important things to consider when wiring a hot tub are equipotential, safety restrictions and hot tub location. The service of a qualified electrician who has experience working with hot tubs is highly recommended.
Equipotential refers to the practice of protecting users from differences in electrical potential in the various components that a typical hot tub contains. To maintain a safe electrical environment, hot tub installers need to bond all of the metallic parts in and around the tub. Bonding law differs in various localities, so be sure to consult with the local inspectorate.
Shut-offs and safety restrictions include devices such as ground fault circuit interrupters, fuses and circuit breakers that are included as part of the hot tub safety chain. Underground wiring is not permitted when working with hot tubs, for safety reasons.
To safely wire a hot tub, it must be located out of clearance range of any overhead electrical or communications cables. Above-ground hot tubs may have a water level closer to an overhead power level than safety regulation allows. When wiring an above-ground hot tub, keep in mind that the maximum water level requirement refers to the tub basin's top edge, potentially shaving inches off of the acceptable distance.