3-wire hot-tub?

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esca9lante

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Recently my friend and I bought a new house with a spa included. I contacted my electrician to change the wiring for the spa a bit. I wanted him to install a GFCI in the main panel, then a fused disconnect at the tub. Currently the setup is a 60A 240V 2-pole regular breaker in the main panel, wired to a box mounted on the house near the tub which contains a GFCI, a pull-out disconnect via a contactor, and a shrill alarm when the GFCI is tripped.

When he got into the wiring, he discovered that the tub was fed by only three conductors! Two hots and a ground, no neutral. I dug up the installation instructions for the tub, and it indeed showed a three-wire hookup: black, red, and green. So he said that trying to wire it with the GFCI I purchased may not work, and I believe him because there is no neutral (white) wire to attach to the center connection screw on the breaker!

My question is, how prevalent are installations of this type? At a previous house I owned, I purchased a spa with a four-wire hookup, and he wired it the way I had hoped to wire this one with no problems.

And, how do GFCI's of this type work? Do they just sense the current on the two hots, and if different, trip?

Thanks, everyone.

Fred S.
 
Re: 3-wire hot-tub?

Fred,
Your tub and the GFCI will work fine.
It sounds as though you still have the owner's manual or something of that sort. If the instructions provided there are followed, it will work just fine. It will show the GFCI hooked up just like normal without a neutral wire on it. It's that simple.
I tried to remember a link to a good site that shows how GFCI's work, but can't remember it. Maybe someone else will.

Many hot tub manufacturers use three wire hook-ups. Sundance, and Jacuzzi used to I know.

mike
 
Re: 3-wire hot-tub?

This is normal construction. Most, if not all, GFCI breakers do not require neutral load connections. In fact, I am not aware of any manufacturer of a 60A 2 pole GCI breaker that has provisions for a load neutral.
 
Re: 3-wire hot-tub?

Fred
I agree that your spa and GFCI should be fine but, if he did not or could not tell you that, you may need a new electrician.
 
Re: 3-wire hot-tub?

Originally posted by jim dungar:
This is normal construction. Most, if not all, GFCI breakers do not require neutral load connections. In fact, I am not aware of any manufacturer of a 60A 2 pole GCI breaker that has provisions for a load neutral.
Click to expand...
I don't recall one that does NOT have a neutral terminal. But, whether the load has a neutral or not, the breaker's neutral pigtail must be connected to the service neutral.
 
Re: 3-wire hot-tub?

From the Square D FAQ website:

Where do you connect the load neutral wire on a QO260GFI?

Answer: The QO260GFI does not have a load neutral connection and is to be used on 240vac 2 wire applications only. Not to be used on 120/240 vac applications where two hot wires and a neutral is required. If a 60 amp GFI breaker is needed on a 120/240 vac system, divide the 120/240 vac loads and put the 240 vac loads on the QO260GFI and put the 120 vac loads on a single pole GFI breaker like the QO115GFI
 
Re: 3-wire hot-tub?

Originally posted by jim dungar:
From the Square D FAQ website:

Where do you connect the load neutral wire on a QO260GFI?

Answer: The QO260GFI does not have a load neutral connection and is to be used on 240vac 2 wire applications only. Not to be used on 120/240 vac applications where two hot wires and a neutral is required. If a 60 amp GFI breaker is needed on a 120/240 vac system, divide the 120/240 vac loads and put the 240 vac loads on the QO260GFI and put the 120 vac loads on a single pole GFI breaker like the QO115GFI
Click to expand...
Okay, you found one brand. HOM and QO 2-pole GFCI breakers are available with up to 50 amps with a neutral; there is no 60 HOM GFCI.

I can tell you that CH and BR types are available with neutrals, along with Murray's.
 
Re: 3-wire hot-tub?

Then I should change my statement to: "Some 60A GFCI breakers do not even include a load neutral connection".
 
Re: 3-wire hot-tub?

Originally posted by jim dungar:
Then I should change my statement to: "Some 60A GFCI breakers do not even include a load neutral connection".
Click to expand...
Works for me! ;)
 
Re: 3-wire hot-tub?

Thanks everyone for your input! Actually I found that Siemens sells a 240V two-pole GFCI with a neutral connector screw (it's between the two hots), with the white pigtail. And this spa is indeed manufactured by Sundance.

The whole reason this started was because the box that contains the GFCI, disconnect, and alarm was AC-humming right outside where my friend sleeps, and he's a light sleeper so it was keeping him awake. It doesn't bother me, though, so I'm going to have my electrician (and he is certified) move the disconnect to my wall and connect using conduit.

Another strange setup there: the conduit that carries the circuit for the spa behind the house doubles as the service earthing connector! There's a bonding jumper inside the main panel between the neutral strip and the conduit connection, and there is no ground rod! I assume (but I may have my electrician check anyway) that the resistance is 25 ohms or less, otherwise we're not up to code.

Fred S.
 
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