3wire 220 to GFCI to 3 wire hot tub


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Old 10-07-10, 07:32 AM
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3wire 220 to GFCI to 3 wire hot tub

I've read a million posts on this topic, but it was probably the one-million-and-first one that covers it and I just haven't seen it.

I have a hot tub. I want it to be hot, bubbly, and fun. Right now it's a pool for bugs.

I have a 3-wire (Black/White/Gnd) from a 220-50a breaker to a GFCI sub panel and a 3 wire (black/white/gnd) from the sub to the hot tub.

How do I wire up the sub panel from the main breaker?

Thanks,

-=Rob=-
 
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Old 10-07-10, 08:49 AM
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Is the tub 240V-only or 120V/240V? Where is the GFCI device and the disconnect relative to the panels?

The main to subpanel is generally 6-3g NM-B if indoors or #6 THHN black,red,white #10 green in PVC conduit if outdoors. The subpanel to tub almost always needs to be #6 THHN black,red,white and #10 or #8 green in PVC conduit.

Black,white,bare is almost never correct for a hot tub.
 
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Old 10-07-10, 08:58 AM
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The ground MUST be insulated on the outdoor portion of the wiring if the tub is outdoors.
 
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Old 10-07-10, 09:17 AM
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Scenario

Ok, here's the whole story.

Hot tub wiring was installed by electrician. Yes, it is outside.

We moved, I took wiring, subpanel, breaker, etc with hot tub. Now I'm re-hooking it up and I *THOUGHT* I knew how to do it but now I'm second-guessing myself. It's been forever since I've worked with 220.

I'm not home at the moment so I don't know the guage of the wiring, I'm going to say it's either 6 or 8. It's extremely thick and hard to maneuver.

So 3 wire to subpanel. Definitely only black/white/gnd. NO red.

Definitely 3 wire to hot tub. Black/White/Gnd. BUT, it's going through blue flex tube (I don't know the real name of it,sorry) from inside the sub-panel to inside the hot tub.

I believe right now, white and gnd from the house and the white pigtail from the gfci are tied tied to a block and the black from the house is on it's own isolated block.

I also think the guy had the black from the hot tub tied to the the black block, and the white went into the gfci breaker. The ground was grounded to the box.

It doesn't "feel right" to me because I'm used to seeing 4wire systems (B/W/R/G) which is why I'm questioning all of this.

Thanks again,

-=Rob=-
 
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Old 10-07-10, 09:24 AM
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If you can verify if the tub is 240 or 120/240 it would help greatly.
 
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Old 10-07-10, 09:29 AM
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Originally Posted by r0bcat View Post
It doesn't "feel right" to me because I'm used to seeing 4wire systems (B/W/R/G) which is why I'm questioning all of this.
I agree, nothing about the existing install sounds correct. The bare ground and recoded white might have been okay on a past code, but I don't think that's been acceptable on a spa for a very long time.
 
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Old 10-07-10, 09:32 AM
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AC Requirements

Downloaded the brochure for it and it's 240vAC all.
 
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Old 10-07-10, 09:36 AM
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"Not to code"

Isn't the purpose of the blue flexible conduit, though? To keep the ground wire "unexposed".
 
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Old 10-07-10, 11:19 AM
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The use of a re-identified conductor in a cable assembly is still allowed for a 240 volt usage. Like I said earlier the ground must be insulated for the exterior portion of the circuit. This rules out usage of a cable assembly.

Sounds like there is nothing salvageable in this project.
 
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Old 10-07-10, 01:04 PM
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Originally Posted by r0bcat View Post
Isn't the purpose of the blue flexible conduit, though? To keep the ground wire "unexposed".
No, the conduit is for protection of the wires from physical damage and to a lesser extend to allow for easy future modifications. The blue flex (ENT) however is not rated for protection or for burial because it is so flimsy. It could be used indoors in a protected environment, but not for the outdoor portion of the spa. Rigid sch. 40 PVC is the minimum conduit for this type of install.

The insulation on the individual ground wire prevents corrosion of the wire in the underground conduit that a bare wire would develop. All outdoor conduits collect water, and the code wants to guarantee that the safety ground to the tub is not compromised by corroded copper. This is also why aluminum wire is forbidden for a pool or spa.

I agree with PC, that the best thing to do here is to start over with the electrical install. You can probably reuse some things like the panel and GFCI as long as those are in working order. Maybe the black/white/bare cable from the main to the subpanel could be re-used but that would require re-identifying the white as red and relocating the GFCI to the main panel which may or may not be possible based on compatibility of the breaker.
 
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Old 10-19-10, 09:49 AM
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Update

Thanks to all who posted on this.

Everything is hooked up and running. I looked up the wiring diagram for the hot tub itself and they only show black/red/gnd to the hot tub. No common. So this is how I wired it per their specifications.

One thing I failed to mention is that the hot tub wiring wasn't going underground. The subpanel was mounted to the house and the hot tub is sitting about 1 foot from there so it was a short piece of wire which is why there was flexible conduit used, not rigid.

Thanks again for everyone's help.

-=Rob=-
 
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Old 10-19-10, 11:35 AM
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Glad you got it.
One thing I failed to mention is that the hot tub wiring wasn't going underground. The subpanel was mounted to the house and the hot tub is sitting about 1 foot from there so it was a short piece of wire which is why there was flexible conduit used, not rigid.
And that was a key piece of info we needed. So long as the wiring to the subpanel is completely inside the house a cable with bare ground can be used. Only the whip from the subpanel to the tub needs an insulated ground. You did use and insulated ground, correct?
 
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Old 10-19-10, 11:53 AM
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Yes, I did. Wiring to sub is completely indoors. Sub to hot tub is 3 wire (insulated gnd) inside flex conduit with less-than 2 foot run.
 
 

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