Hot Tub Electrical Requirements

Hot tubs run on two types of electrical connections.  They can run on 110V/15AMPs which are referred to as plug and play hot tubs or they run on 220V/50AMPS which are referred to as hard wired hot tubs.  

Generally speaking hot tubs are designed to perform optimally and operate most efficiently on a 220V/50AMP hard wired, GFCI protected circuit. That is because all of the equipment can run at the same time (no limitations) and because 220v units feature a larger heater (5.5kw) which can heat the water much faster (than a 110v).   Although 220V/50AMP circuits are the most common there are some models designed to run on 60-100 AMP circuits.  Higher amperage circuits may be required if the hot tub or spa has multiple jets pumps or multiple heaters such as the case with dual zone swim/exercise spas which require 100 amps.  Dual zone swim spas are actually two separate units with separate heaters, equipment, and controls but they are integrated into one shell. 

It is the obligation of the hot tub owner to make sure that the electrical connections are made by a qualified homeowner or licensed electrician in agreement with the National Electrical Code (NEC).  There are several sections of the NEC code that require compliance (ie. section 422-20 and section 680-42).  It is also important to make sure you are in compliance with any local and state electrical codes during installation.

Below are a few general requirements and precautions regarding a 220-240V electrical installation, however, it is important to reference your hot tub owner’s manual for specific requirements for your manufacturer and model of hot tub

  1. The electrical connection to the hot tub must be single phase, 220-240 volt 4 wire.  The four wires consist of two hots, one ground, and one neutral and must be hard wired to the terminals inside the hot tub control box. The recommended wire size is 6 AWG copper although depending on distance and length of run could be larger.
  2. A shoe box sized metal box, called a disconnect box,  must be installed no closer than 5 feet from the hot tub and no further than 15 feet and must be easily accessible to the hot tub users.
  3. A “GFCI”  (Ground Fault Circuit Interrupter) must be used. The GFCI should also be 50AMPs. This is a safety mechanism designed to automatically shut power off to the hot tub when a fault or leak from one of the supply conductors to the ground is detected.
  4. The electrical circuit for the hot tub must be dedicated and not shared with any other electrical things such as appliances, electric yard tools, power tools, etc.   it is important to note that if the hot tub circuit is shared with any other electrical loads then it will result in nuisance tripping of the breaker and is a safety hazard.
  5. It is important to note that use of wrong wire gauge sizes or improper electrical connections may cause nuisance tripping, damage to fuses, damage  to hot tub components, damage to electrical box, void hot tub warranties and create a safety hazard.

The other type of hot tub electrical connection is a 110V/15AMP.  These type of hot tubs run on a regular 15-20 amp household circuit. They are extremely convenient since they typically don’t require an electrician or any of the aforementioned hardwired electrical steps mentioned above.   Most manufacturers of 110v models supply the cord with a built-in GFCI for safety.  110v units do require a dedicated outlet so it is important to identify a proper outlet that isn’t shared with any other outlets in the home. If the hot tub is plugged into a shared outlet and other electrical items are run at the same time as the hot tub then it can cause nuisance tripping of the breaker and ultimately create a safety hazard.