How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Terri Your Own Question
Terri, Handywoman
Category: Home Improvement
Satisfied Customers: 104
Experience:  Masonary construction background, home and commercial, home repair specialist
Type Your Home Improvement Question Here...
Terri is online now
A new question is answered every 9 seconds

how to hook up a hot tub ...

Customer Question

how to hook up a hottub
Submitted: 9 years ago.
Category: Home Improvement
Expert:  Terri replied 9 years ago.

Different spa & hot tub manufacturers have different takes on which is best for there tub (120Volts or 240Volts). I have found that in all but the warmest climates 240V is the way to go. This is due to the fact the when a spa is run on 240V the wattage of the heater in most cases is as much as quadrupled, leading to faster recovery times. Also spas / hot tubs that use 120Volt heaters will shut the heater down when the spas jets are run at high speed. This leads to more heat loss during usage.

Typical electrical requirements are (but may vary with different equipment - so check with your dealer for specifics): 120V 20amp systems, require a Ground Fault Interrupter (GFCI) which is in many cases supplied with the "plug in cord", from the spa dealer. With these systems it is worth noting that the electrical plugs in many houses are for a 15amp outlet and may not be "dedicated" (where that are no other outlets or appliances on the line). And thusly may require an electrician anyway. Without the usage of proper circuitry you may not only void your equipment warranty you may be causing a fire hazard.

240Volt 30, 40 and 50 amp systems, Spas / hot tubs that use 240V only in their operating systems will generally be wired with a three-wire 240V run. But keep in mind that many spa manufacturers will use a four-wire system, especially if they use a 120V ozonator, pump or air blower. All of these will require a proper amperage GFCI and should only be wired by a licensed electrician. One hint when looking for an electrician is to ask if they have ever wired your particular type of spa. Many good electricians have not wired a four-wire spa and can easily miss-wire the GFCI causing it to trip when power is first applied. It is a good idea to see if the spa dealer you are purchasing from has anyone on staff that knows how a four wire GFCI should be wired, so if the electrician has problems, they can speak with someone on staff to clarify the procedure for them. Many spa manufacturers that use this type of electrical hookup will have someone on staff that the electrician can speak with directly, if problems occur. Always consult local electrical code, before wiring a 240V tub, this will keep confusion down to a minimum over issues like size of wire to be used, etc. When in doubt, put in heavier wire!

Always use all copper conductors, the money saved by going to aluminum or copper coated aluminum, will be lost in increased power bills, and in some cases the cheaper wire can be a fire hazard, and/or will void portions of your warranty.

GFCI Installation on Four Wire 240V Systems;

In new spa / hot tub installations it is a common problem to have a miss-wired GFCI.

NOTE that there are different models of GFCI used in the market, the following description is generic.

To properly wire a GFCI on a four wire 240V installation, when using a sub-panel box, all four wires should be brought out from the main box. The two hot legs should be attached to the GFCI breaker at the proper locations, then come out of the GFCI breaker and be run to the spa. The neutral leg from the main box should come out and be attached to the neutral bus located on the side of the breaker. The neutral pigtail on the breaker should then be attached to the other side of the neutral bus. There is a location for another neutral lead that goes out to the spa from the breaker, this neutral wire should be run out to the spa. The ground wire from the house and ground from the spa should be bonded together in the sub-box. If the neutral and ground are not kept separate in this fashion the spa will instantly trip the GFCI breaker.

See the instructions that come with the GFCI for additional information.

If you have to have your service upgraded to handle the new tub;

There is an old saying in the spa & hot tub business. If you need to do a service upgrade to put in your tub, you should have already done it. Plus, generally speaking, an electrical service upgrade is a home improvement that will pay for itself when the house is sold.

Because of the improved heating characteristics and efficiency of a 240V tub over a 120V model many people that purchase 120V/240V convertible spas wind up going with the 240V

Please remember to ACCEPT my answer Thank-you so much,justerri

JustAnswer in the News:

Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
Web sites like
...leave nothing to chance.
Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.
Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.
I will tell you that...the things you have to go through to be an Expert are quite rigorous.

What Customers are Saying:

  • You did one super job of explaining to me everything there is to know about this fridge. I'm looking forward to asking you questions in the future. Jimmy Bagley, IA
< Previous | Next >
  • You did one super job of explaining to me everything there is to know about this fridge. I'm looking forward to asking you questions in the future. Jimmy Bagley, IA
  • Thank you for the expeditious answer. It's good to know you're out there and awake in the wee hours when I finally have time to ask questions about my Jenn Air. Jean Riverhead, NY
  • Wonderful service, prompt, efficient, and accurate. Couldn't have asked for more. I cannot thank you enough for your help. Mary C. Freshfield, Liverpool, UK
  • This expert is wonderful. They truly know what they are talking about, and they actually care about you. They really helped put my nerves at ease. Thank you so much!!!! Alex Los Angeles, CA
  • Thank you for all your help. It is nice to know that this service is here for people like myself, who need answers fast and are not sure who to consult. GP Hesperia, CA
  • I couldn't be more satisfied! This is the site I will always come to when I need a second opinion. Justin Kernersville, NC
  • Just let me say that this encounter has been entirely professional and most helpful. I liked that I could ask additional questions and get answered in a very short turn around. Esther Woodstock, NY

Meet The Experts:

  • Brian



    Satisfied Customers:

    Licensed Architect- 17 years, L.E.E.D. AP
< Last | Next >
  • Brian's Avatar



    Satisfied Customers:

    Licensed Architect- 17 years, L.E.E.D. AP
  • The Home Smithy's Avatar

    The Home Smithy

    Home Builder

    Satisfied Customers:

    #1 Home Improvement Expert 30+ years experience
  • Steve G.'s Avatar

    Steve G.


    Satisfied Customers:

    VP of electronic repair company and home theater advisor.
  • StructuralEng's Avatar


    Civil Engineer

    Satisfied Customers:

    Licensed Structural Engineer
  • Eric M. Bright's Avatar

    Eric M. Bright

    We Don't Comprehend the Word Can't!

    Satisfied Customers:

    I've been been doing things for my clients that others have said cant be done for over a 1/4 Century
  • Rich's Avatar


    Home Improvement Enthusiast

    Satisfied Customers:

    Over 35 years construction and home maintenance experience
  • Phil's Avatar


    Mechanical Engineer

    Satisfied Customers:

    Retired contractor, 51 years experience