Hot tub and grounding rod?

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Old 11-05-13, 07:22 AM
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Hot tub and grounding rod?

I'm getting ready to wire my new hot tub and was under the impression that I needed a grounding rod. The grounding rod is already in the ground but I've been reading that it may not be required and some even say it may even be more dangerous to use it. Everyone's situation is a little different so I want to get my facts straight before wiring everything up.

My plan is to use a subpanel in the house to wire the hot tub. The sub panel uses the main panels grounding rod. Since the subpanel is not GFCI and I know I need a shut off in view of the tub, I plan to add a GFCI spa panel near the tub. The hot tub is separate from the house, on a wood deck, and roughly 60-70 feet of wire from the sub panel and 150-ish feet of wire from the main panel. Everything will be wired up with 6 ga wire.

Since I jumped the gun and the grounding rod is in place, I'd kind of like to use it if it won't create a dangerous situation but I'd like to avoid doing something stupid too. haha
 
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Old 11-05-13, 08:50 AM
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Welcome to the forums!

No, you don't need a separate path to ground. OTOH, with the distances from your main panel and disconnect, why not?

I've been reading that it may not be required and some even say it may even be more dangerous to use it.
Did they say why? So long as there is no connection between neutral and ground anywhere in your wiring, including within the tub's connections, there should be no potential for harm to your system.
 
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Old 11-05-13, 10:05 AM
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The "why not" is kind of my opinion especially considering a serious problem requiring a ground would have to travel so far but I'm not an electrical expert at all.

I read that having a voltage gradient would make the grounding rod a hazard. Not sure how or why you'd have a voltage gradient or even how it would pose a hazard with the addition of a grounding rod but that's what some are saying. Others are saying that the grounding rod serves no purpose because an overload would go through the nuetral wire and trip the circuit instead of through the grounding wire. This one doesn't make sense to me since I thought the whole point of a grounding wire was to give the current a place to go in the event of an overload or at least an overload so great that the nuetral wire can't handle it all. I don't know.....
 
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Old 11-05-13, 11:39 AM
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I thought the whole point of a grounding wire was to give the current a place to go in the event of an overload or at least an overload so great that the nuetral wire can't handle it all.
In an overload condition, the current should never see the ground. Ground conductors only come into play when you have a direct short to ground or to the frame of equipment that should be grounded. Even if you do install a ground rod at your spa, you still need a grounding path back to your main service panel and somewhere this needs to be connected to the new ground rod too; possibly at the disconnect.
 
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Old 11-05-13, 02:55 PM
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The code limits us to one Grounding Electrode System (GES = ground rods, etc.) per structure. Other panels attached to that structure may not have a GES.

A breaker panel not attached to that structure must have a GES (two ground rods in your case).

Spa manufacturers have asked me to put a ground rod at their spa to protect and stabilize the control board. I don't know why, but it has fixed some problems.
...I read that having a voltage gradient would make the grounding rod a hazard. Not sure how or why you'd have a voltage gradient or even how it would pose a hazard with the addition of a grounding rod but that's what some are saying. ...
A ground rod only sees voltage during a short(minimal), surge or lightning strike. That's the only time a voltage gradient would exist. These are very short duration events. And it's much better to have a GES for one of these than not have a GES.
 

Last edited by Glennsparky; 11-05-13 at 03:16 PM.
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Old 11-05-13, 05:05 PM
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The tub does not require a ground rod according to the electric code. Just leave it unused.
 
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Old 11-06-13, 06:16 AM
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I think I'm beginning to see the confusion with all of this and it seems like how you define simple words will define your requirements.

Glennsparky says
The code limits us to one Grounding Electrode System (GES = ground rods, etc.) per structure. Other panels attached to that structure may not have a GES.

A breaker panel not attached to that structure must have a GES (two ground rods in your case).
The above sounds like a grounding rod isn't even recommended but actually required but I'm assuming that my new deck (not attached to the house) is considered a structure and my spa GFCI panel with a breaker in it is considered a breaker panel. If my assumptions and understandings are incorrect, please correct me.
 
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Old 11-06-13, 07:01 AM
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Jfw432, you are correct. Two ground rods are required.
 
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Old 11-06-13, 07:52 AM
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Jfw432, you are correct. Two ground rods are required.
I agree that now we know this is a separate structure a ground rod is required, but whether 1 or 2 rods being required is a decision to be made by the AHJ.
 
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Old 11-06-13, 08:31 AM
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The rod would serve the deck panel, not the hot tub.
 
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