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I am installing electrical for a hot tub in my residence. I have a rough idea for a plan that I would like advice on. I'd appreciate your help in pointing out gaps with respect to the NEC.

Hot Tub Power Requirements

240V/60A
Circuit Breaker (2-Pole):  60A
Number of wires:           3
Frequency:                 60 Hz
Current Draw:              45A

Plan

  1. Add a double pole 60A circuit breaker to my service panel. Service panel is on an outside wall of the house roughly 5ft from the ground.
  2. Run 6-3 wire (Q1*) from panel to junction box in crawl space. The wire will punch through a vent leading into the crawl space.
  3. Splice 6-3 wire (Q2*) together at junction box and run to junction box nearest tub.
  4. Splice 6-3 wire (Q3*) together at junction box and run through another vent exiting the crawl space to get to disconnect box. Disconnect box will contain GFCI (Q4*). Box is also mounted above the deck for easy access and on an outside wall which is covered.
  5. Run 6-3 wire (Q5*) from disconnect box to hot tub control box where it gets hard-wired.

    * Q1-Q5 refer to questions I have below.

Diagram

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Questions

  1. What kind of wire is sufficient from the service panel to the first junction box in the crawl space?
    I have read various tidbits, but still do not know what is right according to code. Since this wire is dropping down from the panel outside, it is considered a wet location I believe.

    According to "Article 334 Section II" of NEC 2011, NM and NMS types cannot be used in damp or wet locations; NM/NMS in conduit is not an option either because it is considered a wet location as well.

    UF might be an option in conduit, but I've yet to get a clear answer from this question.

  2. What kind of wire is sufficient between junction boxes in the crawl space?
    I have read crawl spaces are a vague area and should be considered dry locations by definition; otherwise, the crawl space is not doing its designed job. Assuming the crawl space is a dry location, I believe I can use NM-B wire not in conduit.

  3. What kind of wire is sufficient from the junction box in the crawl space to the disconnect box?
    This run seems like a damp location since it is covered. If this is correct, that rules out NM.

    Again, for the same reasons as before, I'm not sure if I can use UF since the wire need to run roughly 8 feet along the house and below the deck, and then upwards about 4 feet to reach the disconnect box above the deck on the outside covered wall.

  4. Is it even feasible / correct to put my GFCI in the disconnect box?
    I will admit, I have not done much research here and I'm simply throwing this out there for advice. I need a GFCI somewhere, but I do not know where is best. My common sense tells me it should be accessible with relative ease (no tools), so it can be reset. In addition, it should be near the hot tub, but not too close. The disconnect box seems like a good place.

  5. What kind of wire is sufficient for this final run from the disconnect box to the hot tub control box?
    This run spans a damp location and wet location. The run will drop from the disconnect box to under the deck, back-track about 5 feet in the damp location, and then be exposed in the wet location for about 4 feet. For all intensive purposes, I believe I should consider this run all as wet essentially.

  6. Are the junction boxes required?
    I thought they would be required due to changing wire type in the crawl space (to reduce cost). However, based on answers to my questions above, perhaps I should be using a different type of wire, in which case, the junction boxes might not be needed.

  7. Are any more components required in the crawl space run?
    I planned to use a single wire between the two junction boxes and staple it on joists every 4' 6" roughly. The run is approximately 32 feet direct. Along the walls, the run would be 44 feet approximately.

Thanks for your time and input. Let me know if more details are needed to accurately answer my questions.

I genuinely enjoy working on projects like this myself. If I find out it is too complex (or required in my area), I have no problem hiring a licensed professional. However, I would at least like to have an equal conversation with them about the work.

  • You ran 6/3 with ground, right? – Tester101 Sep 19 '15 at 23:28
  • Not sure what the cost difference is, but it might simplify the problem if you ran 6 AWG THWN conductors through PVC conduit the whole way. – Tester101 Sep 19 '15 at 23:40
  • Yes, I will need to run ground. Thanks for the THWN suggestion. I hadn't seen this option before and it should be cheaper than UF. If I use THWN, it looks like I wouldn't need the junction boxes either. Love it. – Scott Lin Sep 20 '15 at 3:14

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