Installing your own Hot-tub spa.

Meeting all the site requirements to install a hottub properly can be pretty daunting and the consequences of improper installation can be complete disaster.

In a previous neighborhood, one of our neighbors a few blocks away bought a hottub and decided to save a few bucks by wiring it up himself. He used plain NM (Romex type) household wiring. This was roughly 400% smaller than the wire size needed. It also was not rated for outdoor use. Coupled with using a standard breaker instead of a GFCI, disaster was an eventuality.

Disaster struck only a few weeks later. The wire overheated, the breaker failed, and the house went up in flames and had to be stripped down to the studs and completely rebuilt.

This blog entry is not a step by step guide. It is not intended for those who have not worked with electrical before. It is intended to give you a feel for what must be accomplished to properly install a hot-tub. I disclaim any responsibility for any work you do.

If you are planning to set a hottub on a wood deck, determine the weight limits and consult a structural engineer. Most site plans for hot tubs require something on solid ground or a concrete slab for a large tub. Hot-tubs are REALLY heavy and get way heavier when full of water.

Hot-tub delivery with 3 men and a dolly to move the tub into position.

Also, Please make sure that you research both current relevant codes and local codes as well as following any additional instructions that come with your tub. Additionally, pull an electrical permit where required.

Find a convenient space. Note the light overhead. This circuit had to be upgraded to GFCI to meet code once the tub was in place.

You will need power to your chosen location. A 50 or 60 amp dedicated circuit depending on the specifications in your owner manual.

Example of a common 50 amp disconnect.

*The National Electrical Code (NEC) 680.12 specifies installation of an approved manual disconnect device. It must be adjacent to the hot tub, at least 5 feet away, and within line of sight. The NEC also requires a 120V receptacle within a 10-20 foot distance from the spa.”

Pull appropriate gauge wire to your disconnect from main breaker location.
Example of a wired 50 amp box without breaker installed.

During hot tub wiring, copper wire is recommended with THHN (thermoplastic nylon) insulation. Avoid aluminum wire. The recommended minimum hot tub wire size in most cases is 6 AWG copper.

Note: some manufacturers (Especially Hotsprings) have special breaker requirements and may provide a “disconnect kit” with your spa.

Example of a special “Hotsprings” Spa disconnect with 2 breakers.
Protect all THHN wiring with conduit.
A much tighter fit once the breakers are in.

Next pull liquid tight flex conduit suitable for the number and size of conductors you have to the disconnect box and knock out the appropriate punch hole. (Make sure you still have power off to this breaker!)

I pulled my THHN wire through the conduit prior to trying to connect it since it can be difficult to pull multiple conductors through after connecting the conduit hose to the disconnect box.

Note: it is substantially easier to pull these wires when you have at least 2 people while doing this part.

Connect L1, L2, neutral and ground wires to breaker per hot-tub instructions.

Connect the flex to the hottub with locking nut.

Make necessary connections to the hot-tub electrical box. With my unit the connections were “push-in” style with no screw down needed.

The hot-tub powered up but kept getting errors. After a call to the store, the manager informed us they disconnect the recirculating pump at the store when they have them in the showroom so they can demo the lights and the sound system. I found the two loose wires.

I turned the power off and found the disconnected wires, plugged them back in and everything worked fine.

Time for a soak!

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