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  • Aug 10, 2012, 09:24 PM
    chebowitz
    Installing a disconnect for a hot tub
    I recently installed a hot tub where there is a home-run from the hot tub to a 50 amp 240v GFCI in my circuit breaker panel in the basement (I ran #6 wire for the black, red, white and green). Everything works fine. I now need to install a disconnect near the tub. I would like to confirm if it's okay to have the disconnect just for the two hots, i.e. the black and red wires and leave the neutral/white alone (so it remains uninterrupted)? Also, if I ground the disconnect box directly to the circuit breaker panel is that sufficient (i.e. the green home run to the hot tub will also be uninterrupted)?
  • Aug 11, 2012, 03:30 AM
    tkrussell
    If you can, somehow, leave the neutral unbroken passing through the disconnect, sure.

    I am not sure what you mean by: "Also, if I ground the disconnect box directly to the circuit breaker panel", by doing the same with the ground wire. How can it pass through the disconnect unbroken and still ground the metal box of the disconnect?
  • Aug 11, 2012, 07:11 AM
    chebowitz
    Quote:

    Originally Posted by tkrussell View Post
    If you can, somehow, leave the neutral unbroken passing thru the disconnect, sure.

    I am not sure what you mean by: "Also, if I ground the disconnect box directly to the circuit breaker panel", by doing the same with the ground wire. How can it pass thru the disconnect unbroken and still ground the metal box of the disconnect?

    tkrussell: Thanks for your answer. To be clear, you're saying the neutral wire is okay to leave unbroken, correct?

    Re: your ground wire question, I'm planning on running a #12 bare copper right from the circuit breaker panel rather than cut the #6 ground to the hot tub. Here's the reason.

    When I ran the original wiring, I didn't plan for a disconnect. Fortunately, I had an LB in the middle of the conduit run that's about 12 feet from the planned disconnect location. At this point, the simplest - and least expensive - solution I came up with was to cut a hole in the LB, run a 1" conduit to the disconnect box, cut the two hot leads in the LB and then splice in a short #6 wire run for the pair of hot leads "to and from" the disconnect through the (new) conduit. I have spare #12 (bare) wire that can easily be pulled from the basement breaker panel that will provide my disconnect ground, hence my question.
  • Aug 12, 2012, 03:09 AM
    tkrussell
    Do not do what you plan with the #12. Cut the ground in the #6 cable. How many splices you plan to do in the 1 " LB?

    You will create more points of failure with all of these splices.

    Why not just terminate the LB to the new disconnect, and then continue on with new #6 wire to the tub?

    You plan will have DIY all over it.
  • Aug 13, 2012, 11:54 AM
    chebowitz
    1 Attachment(s)
    Quote:

    Originally Posted by tkrussell View Post
    Do not do what you plan with the #12. Cut the ground in the #6 cable. How many splices you plan to do in the 1 " LB?

    You will create more points of failure with all of these splices.

    Why not just terminate the LB to the new disconnect, and then continue on with new #6 wire to the tub?

    You plan will have DIY all over it.

    Thanks again tkrussell for your follow up.

    When you write do not run the #12 ground as planned (i.e. directly from the circuit breaker panel to the disconnect box), is there a safety issue? While I'm far from an expert, I thought a direct ground from the circuit breaker panel would be as good as it gets.

    Your suggestion to "... terminate the LB to the new disconnect, and then continue on with new #6 wire to the tub", while a good one, unfortunately is not an option given where the LB's location. So my only choice is to run a new (1") conduit as previously described. Additionally, 1" is the maxiumum knockout for the disconnect box. BTW, the LB is a 1 1/2" as is the original conduit run, so there's enough room for the splices in the LB. I plan on wrapping the wire nuts with electrical tape to help mitigate splice issues.

    The plan is to have a total of four splices in the 1 1/2" LB: two each for the two hot leads. See attached "Hot Tub wiring diagram".

    I appreciate your comment regarding "more points of failure" however, given my only option of a new conduit run, using the original #6 ground for the disconnect box will create another splice in the LB and that seems to exacerbate your point. Additionally, it will crowd the 1" (new) conduit to the disconnect, although I recognize the capacity for 1" conduit is 6 - #6 wires. This is why I thought the #12 independent ground from the circuit breaker panel directly to the disconnect box accomplishes both the grounding requirements and the crowded conduit concern.
  • Aug 14, 2012, 06:14 AM
    tkrussell
    Running a separate ground wire, not part of a cable or enclosed raceway with the branch circuit conductors is not allowed by Code.

    Splicing in a condulet, such as an LB is only allowed if the volume of space is noted on the fitting, which problably is there considering it is a PVC unit. Next need to determine what space the wiring needs.

    #6 needs 5 cubic inches of space for each conductor. Your sketch shows 6-#6 wires to be spliced, so a total of 30 CI is needed, never mind the wires that run straight through the LB.

    What is the cubic inch of space of this LB?

    How about continuing from the LB to the tub, and then a conduit to the disconnect, do all connections in the tub connection box?
  • Aug 14, 2012, 11:00 AM
    chebowitz
    1 Attachment(s)
    Quote:

    Originally Posted by tkrussell View Post
    Running a separate ground wire, not part of a cable or enclosed raceway with the branch circuit conductors is not allowed by Code.

    Splicing in a condulet, such as an LB is only allowed if the volume of space is noted on the fitting, which problably is there considering it is a PVC unit. Next need to determine what space the wiring needs.

    #6 needs 5 cubic inches of space for each conductor. Your sketch shows 6-#6 wires to be spliced, so a total of 30 CI is needed, nevermind the wires that run straight thru the LB.

    What is the cubic inch of space of this LB?

    How about continuing from the LB tothe tub, and then a conduit to the disconnect, do all connections in the tub connection box?

    tkrussell: I greatly appreciate your expertise and ongoing responses on this.

    Doing the connections in the hot tub, unfortunately, is not an option either given the nature of the run, etc.

    I've attached a new drawing (Hot Tub wiring diagram-rev1) which eliminates the direct #12 ground wire from the circuit breaker panel to the disconnect. Instead, I am splicing the original (#6) ground within the LB and running a #6 ground lead through the 1" (new) conduit to the disconnect box. As you will see, this creates 5 splices in the 1 1/2" LB. Per the manufacturer's spec, the 1 1/2" LB volume is 32 cu. in... would that accommodate what the new diagram shows? Is this design within code?
  • Aug 14, 2012, 11:05 AM
    tkrussell
    Stupid question, but can you change the LB to a junction box?

    Each wire that needs to be spliced require 5CI of space. Now you have ten, times 5 CI each, totals 50 CI needed, and the LB is much too small.

    How about some photos of the panel, LB local area.

    There has got to be a way without splicing in the LB.
  • Aug 14, 2012, 12:09 PM
    chebowitz
    Quote:

    Originally Posted by tkrussell View Post
    Stupid question, but can you change the LB to a junction box?

    Each wire that needs to be spliced require 5CI of space. Now you have ten, times 5 CI each, totals 50 CI needed, and the LB is much too small.

    How about some photos of the panel, LB local area.

    There has got to be a way without splicing in the LB.

    I'm not at the property so can't get photos today. But I'm pretty darn sure given the location of the various items, the disconnect box knockout restrictions, what's already been run, etc. I have what I have (I'll see if I can quickly draw a to scale sketch of the layout and post that).

    Re: changing to a junction box, maybe, but that would require my cutting all the original wires (at this point it's really only cutting the white/neutral which, I guess is not a big deal). And then it would be cutting the original 1 1/2" conduit at each end of the LB. I suspect a big enough juction box would be larger than the LB so the conduit may still reach. Also that would mean having a separate 1" conduit to the disconnect and a separate 1" conduit from the disconnect. I'll have to look into this further (albeit, this switch is quite a pain but it's my own fault).

    If I understand how your calculating the 5 CI / spliced wire requirement, there may actually be 11 as follows: 2 black and 2 red going to the disconnect; 2 black and 2 red coming from the disconnect; and 3 green (look carefully at the "rev1" diagram again... the green is a three wire splice). So if I'm right with this, then if I have to cut the white, I'll be adding another 2 spliced wires which will bring the total to 13 spliced wires x 5 = 65 cu. in. junction box requirement. Do I have this right?
  • Aug 14, 2012, 12:59 PM
    tkrussell
    Yes, you have the wire fill calc correct.

    Do not let knockout size stop you, they can be made bigger, or smaller, and conduit can be made longer.

    If this LB is outside, the junction box will need to be either NEMA 3R or NEMA 4 rated, raintight or water tight.

    Photos will sure help figure this out. The splicing all of these #6 in an LB is not going to work.

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