OK to run separate ground?

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Old 02-24-10, 04:06 PM
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OK to run separate ground?

I have an electric cook top circuit (30A, 240V) that I am not using anymore since I installed a gas cooktop. I'd like to repurpose this circuit for a hot tub. The problem is the wire does not have a ground. It looks like the wire runs at some severe 90 angles in the wall coming out of the main panel, so I am very reluctant to try and pull new 3-wire cable.

Would it be OK to run a separate ground wire? If so, do I need to feed it to the main panel or can I connect it to the ground rod beneath the panel? Can I connect it to the water pipe system instead (it's a good ground, no pex or pvc connectors)?
 
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Old 02-24-10, 04:50 PM
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Big gotcha is are you going to have to extend this cable? I assume the hot tub isn't going in the kitchen. In general ungrounded circuits can't be extended. Hot tubes have many safety requirements which vary depending on if it is inside or outside. You also haven't told us the electrical requirements of the hot tub. Running new cable is probably going to be best.
 
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Old 02-24-10, 05:10 PM
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In addition to Rays comments, all the hot tubs I have installed required a 240 volt 50 or 60 amp circuit.
 
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Old 02-24-10, 07:24 PM
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It's a 30 Amp hot tub. Hard, but not impossible, to find. Some Columbia, Dimension 1, and Jacuzzi spas can be configured for 30A service (via DIP switches).

Also, I extended the circuit from the kitchen by splicing in a 3-wire cable, which leads to a fused disconnect. The splice is in an accessible box (my understanding is this is OK, per the NEC). It was when I made the splice, I discovered the lack of the ground wire in the old circuit. Now, I just want to safely ground the new 3-wire that leads to the disconnect. There is a good ground (water pipe) near the splice box.
 
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Old 02-24-10, 07:50 PM
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Originally Posted by lusth View Post
There is a good ground (water pipe) near the splice box.
The code does not recognize water pipes as legal equipment grounds. The only approved grounds are the ground bus of the originating panel of the circuit or a point along the grounding electrode conductor. Furthermore, it is pretty clear that retrofit grounds are intended for grounding existing circuits only -- not new ones. I do not believe your approach is within code.

What type of GFCI device is used? What is the exterior wiring method?
 
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Old 02-24-10, 07:52 PM
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The safe way to do it is to run a new circuit with a ground wire and use a GFI breaker disconnect spa panel at the tub.
 
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Old 02-24-10, 08:00 PM
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Lower amps often mean heat for the water isn't continuous or less. Better to run a new circuit for full amperage or you may end up with less then satisfactory results.
 
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Old 02-25-10, 04:46 AM
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Exterior: In conduit to a disconnect. From the disconnect to a 40A (rated) panel with a 30A 2P gfci-circuit breaker. From the breaker to the hot tub.

So what you all seem to be saying, is that running a separate ground to the main panel would be safe, though maybe or maybe not code, depending on your interpretation of retrofit?

The reason for the 30A tub is there are already two sub panels hanging of the main. I don't think my system can spare another 20 or 30 amps without a major redo. Also my sister has a 110V hot tub in northern Ohio and it heats just fine (no jets when it's very cold out though). I think 240V 30A will be plenty in the deep South.
 
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Old 02-25-10, 08:15 PM
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Originally Posted by lusth View Post
Exterior: In conduit to a disconnect. From the disconnect to a 40A (rated) panel with a 30A 2P gfci-circuit breaker. From the breaker to the hot tub.

So what you all seem to be saying, is that running a separate ground to the main panel would be safe, though maybe or maybe not code, depending on your interpretation of retrofit?

The reason for the 30A tub is there are already two sub panels hanging of the main. I don't think my system can spare another 20 or 30 amps without a major redo. Also my sister has a 110V hot tub in northern Ohio and it heats just fine (no jets when it's very cold out though). I think 240V 30A will be plenty in the deep South.
"The safe way to do it is to run a new circuit with a ground wire and use a GFI breaker disconnect spa panel at the tub."

I still think you should run a new circuit with a ground wire. If you go ahead and do it your way, be sure the disconnect with the GFI breaker is NEMA3R rated (raintight). The safe way to do the whole thing is to follow the NEC.
 
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Old 02-26-10, 06:19 AM
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The gfci panel is an outdoor panel. I assume that means it is rain tight?

Any suggestions for pulling a new wire? The main panel is exterior (!). I assume I would cut the old wire where it drops down into the crawl space, attach the new wire to the panel end of the cut, and then pull the new wire into the panel by pulling the old wire back out of the panel.

What if the old wire is stapled in the walls?
 
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Old 02-26-10, 09:34 AM
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What if the old wire is stapled in the walls?
It probably is. Simpler to abandon in place and shove out of the service panel into the wall. Do the same at the kitchen end.
Any suggestions for pulling a new wire? The main panel is exterior
Yes. Run conduit down the ouside wall to the crawl space and across. Be sure to use an insulated ground.
 
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Old 02-26-10, 03:36 PM
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Will do. Thanks for the help!
 
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