Wiring 60A Hot Tub and Sub Panel - Questions

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Old 08-20-14, 05:27 AM
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Wiring 60A Hot Tub and Sub Panel - Questions

Hi All,

Looking to wire up my Sundance Optima hot tub which is a 60Hz tub and is rated at a 240V/60A. The manual specifies a 3 wire set-up, not a 4 wire.

Here's what I've got in hand:

Breaker: 2-pole 60A breaker at the main
Indoor Wiring: 6-3 Romex wiring from main to sub panel (NM-B 6G with 10G ground)
Disconnect: Midwest spa disconnect box with 60A GFI
Spa Whip: Liquid-Tuff direct buriel LFNC-B
LB Conduit body

The subpanel disconnect box will be just 25 feet from the main. The tub will be approx 8 feet from the disconnect, all up against a basement wall (outside). The 6-3 Romex will be used for inside areas only and will change over to the spa whip behind the tub within the LB conduit body. The spa whip will be 3 feet in length outside the tub.

Here are some questions though, if anyone wants to weigh in:

1. Is there any problem anyone can see with the config above?

2. This is up against a basement wall. I am thinking making the 8 ft run from the disconnect to just behind the spa, inside the basement rather than outside (where I'd otherwise need to run conduit outside). This would in theory allow me to use the same NM-B wire from the disconnect to the LB conduit body behind the tub and be much clearer visually. Just want to check though to make sure there are no issues with this.

3. If I do make the run inside the basement, are there any issues with connecting the wires (securely with NM twin screw clamp connectors) through the knockouts on the back of the subpanel through the basement wall, and then caulking or foaming to ensure a water tight seal behind? Or does the conduit have to come out the bottom of the disconnect? I've seen both done, but it is certainly most common to see it coming from the bottom into conduit and then in/out of house.

The plan is to have it all checked out by qualified electrician before flipping the switch but any thoughts or insights on the config and questions above would be greatly appreciated!

RB
 
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Old 08-20-14, 06:36 AM
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1. Is there any problem anyone can see with the config above?
sounds good to me


2. This is up against a basement wall. I am thinking making the 8 ft run from the disconnect to just behind the spa, inside the basement rather than outside (where I'd otherwise need to run conduit outside). This would in theory allow me to use the same NM-B wire from the disconnect to the LB conduit body behind the tub and be much clearer visually. Just want to check though to make sure there are no issues with this.
yes..you may run back of the wall


3. If I do make the run inside the basement, are there any issues with connecting the wires (securely with NM twin screw clamp connectors) through the knockouts on the back of the subpanel through the basement wall, and then caulking or foaming to ensure a water tight seal behind? Or does the conduit have to come out the bottom of the disconnect? I've seen both done, but it is certainly most common to see it coming from the bottom into conduit and then in/out of house.
through the knockouts on the LOWER back of the subpanel through the basement wall,
sounds good

caulking or foaming to ensure a water tight seal behind the box to seal the wall
holes
 
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Old 08-20-14, 11:51 AM
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It will be a pain to splice in the LB. Also the LB would need to be marked with the cubic inch capacity before being used to contain the splice.
 

Last edited by ray2047; 08-20-14 at 11:57 AM. Reason: I>It
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Old 08-20-14, 03:29 PM
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It will be a pain to splice in the LB. Also the LB would need to be marked with the cubic inch capacity before being used to contain the splice.
maybe use a PVC box................8x8x4?....................or a cheep A/C disconnect gives you a box and lugs to connect to.
 
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Old 08-21-14, 07:19 AM
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Thanks

Hi All,

Many thanks for this! OK, I will use the lower knockouts in the disconnect and foam for sealing. And good point on it likely being a pain to splice in the LB box. So what I think I will do then is to connect inside the basement on the other side of the wall from the LB, in a metal box, rather than in the LB.The LB can just serve as the right angled junction with the spa whip.

This is very helpful everyone - thank you!

RB
 
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Old 08-25-14, 04:52 AM
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Update and Question - 8G / 6G Ground

Hi All,

So far so good. Almost everything is in. Decided to go with a steel junction box inside the wall behind the LB body, so no splices are actually in the LB body.

Just one question if anyone knows the answer -- Where the spa whip connects to the NB-M at the junction inside the wall, the spa whip has the 6 gauge ground (green shielded) and the NM-B has 8 gauge unshielded... and this what runs up to the disconnect inside the house.

Is it OK that it is 8 gauge unshielded for this run inside the house (and of course for connecting to the GFI in the disconnect)?

RB
 
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Old 08-25-14, 06:02 AM
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Is it OK that it is 8 gauge unshielded for this run inside the house (and of course for connecting to the GFI in the disconnect)?
Yes. BTW - the disconnect is require to be on the outside of the house and within sight of the spa. Install it in place of the LB.
 
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Old 08-25-14, 09:47 AM
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Thanks Tolyn. Yes, The spa disconnect box is 12 feet from the tub (more than 6 ft), in sight of the spa. It's a little farther down the wall from the LB body.

To paint a picture, the tub us up against an outside basement wall. The 6-3 NM-B Romex was used for the run from the main to the disconnect (25 ft) and then again from the disconnect, box back inside, along the wall (15 ft) and back out behind the tub at the LB conduit body when it connects to the spa whip.

It's that last bit is where I want to make sure is OK, where I've connected the whip's shielded 6 gauge ground to the NM-B's unshielded 8 gauge (inside) and that is run inside 15 ft to the outside disconnect box and attached there to the GFI. Just wanted to make sure it's OK going to the smaller wire for that inside run to the disconnect as most of the connections I've seen online have shown the GFI connection to be a 6 gauge shielded.

If it's OK then great, that's how I've wired it. If not then it's off to Home Depot Does this set-up still sound like it's done fine?

RB
 
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Old 08-25-14, 10:07 AM
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Yes, that sounds ok.

Just to double check things, how did you connect the spa whip to the LB?

Just a note it is insulated wire, not shielded.
 
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Old 08-25-14, 01:22 PM
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And the ground in the NM-B cable would be a #10, not a #8.

The 6-3 NM-B Romex was used for the run from the main to the disconnect
Looking to wire up my Sundance Optima hot tub which is a 60Hz tub and is rated at a 240V/60A. The manual specifies a 3 wire set-up, not a 4 wire.
You could have saved some money by using 6-2 NM-B cable rather than 6-3. All you need is a 3-wire circuit for 240 volts, like the manual specifies. The only advantage of running 6-3 NM-B is to be able to add a single pole breaker to the spa panel for a 120 volt GFCI circuit which I don't think has been mentioned.
 
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Old 08-25-14, 01:38 PM
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Thanks CasualJoe. Right, the ground is #10 rather than #8. My error. The actual Romex reads AQG 6 CU 2 CDR with AWG 10. TYPE NM-B - 600 VOLTS. Does this change the conclusion that it is fine to connect to the #6 from the spa whip to the disconnect (inside)?

On the cable, this was left wiring over from another job so it was free - so the price was right
 
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Old 08-25-14, 01:47 PM
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Just to double check things, how did you connect the spa whip to the LB?
The whip is connected with two water-tight threaded connectors (male/female) One threads into the ship and the other cements to 3/4 PVC and then into the LB female connection.

Also, have realized (thanks CasualJoe) since that the ground is #10 insulated (rather than #8). Is this still OK?
 
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Old 08-25-14, 03:12 PM
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For 60 amps, a #10 equipment grounding conductor is fine.
 
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Old 08-25-14, 03:30 PM
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The disconnect must be a minimum of 5' horizontally measured from the waters edge unless it is separated by a fence or other barrier?
Geo
 
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Old 08-25-14, 03:32 PM
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See post #8. It is 6' away.
 
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Old 08-25-14, 03:36 PM
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OH MY!------------------
Geo
 
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Old 08-25-14, 04:51 PM
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Some of the tub instructions call for a #6 grounding conductor. The NEC feels a #10 is adequate. I suspect the instructions were written by a lawyer or someone that did not know the NEC.
 
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Old 08-25-14, 06:30 PM
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The actual Romex reads AQG 6 CU 2 CDR with AWG 10. TYPE NM-B - 600 VOLTS.
That would be 6-2 NM-B, the ground wire is not counted.
 
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Old 08-26-14, 07:04 AM
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Thanks

Hi All,

Thanks for your help. To be safe, I switched out the cable from disconnect to LB with all #6 insulated wiring. Good peace of mind to have it all the same heavier gauge. It's now up and running.

And to clarify for those that are curious on the thread, as mentioned in post #8 the disconnect is 12 feet from the spa and in line of sight. So all set there as well. Just need to add a GFI outlet within 25 feet and will be 100%.

Thanks for all your help everyone.

RB
 
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