Spa Wiring, for both gas and electrically heated spas

HouseDepot install both a)Electrically heated and b)gas heated supply. 
a)The Electric heated supply requires, 50A, 240V dedicated lines from the panel to the electrcially heated spa location. The supply wires should be gfi protected for safety. The price varies depending on the accessibility of main panel. The electrical installation cost is from $1500, and requires ESA inspection.
b)spa heated by natural gas, the initial cost is more than the electrically heated spa, as it needs both electrical wire(15A, is usually sufficient), gas piping(most probably needs underground gas piping), and a gas boiler to heat the water. This system is very similar to swimming pool heating.

A simple demonstration for spa/pool wiring(HouseDepot)