Grounding of spa panel some distance away from the house.

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Mr. Serious

Mr. Serious

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Oklahoma, USA
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Electrical Contractor
We just today finished installing a feeder to a spa. The feeder goes for about 35 feet along the house and then for about 60 feet out to a 6-space panel with a 50A GFCI breaker for the spa and a 20A circuit for a receptacle. Then about 8 or 9 feet to the spa (more wire than that because it goes down and back up).

It passed inspection, but I was thinking about it after we were done and thought we should have installed two ground rods out at the spa panel because it is separate from the house. Wouldn't it be considered a separate structure in need of its own grounding under the NEC?

Separate question, somewhat related: does a self-contained spa need to be bonded back to the panel serving it with #8 solid copper? I think it actually does not, but it would if it were built into the concrete like a pool, instead of self-contained.

One time I also ran across a site where they wanted a new spa circuit to come off a pre-existing pool panel, but the panel was some distance away from both the house and the required spa disconnect. In this case, would we need ground rods both at the pool panel and at the spa disconnect? The distances involved were house to pool panel about 130 feet, then pool panel to spa about 90 feet back towards the house.
 
If the panel is supporeted on a post, ect. it is likely deemed "equipment" ans the '17 Code clarified that was not a "structure" so no grounding electrode is required, As far as equipotential bonding of the outdoor spa, it would be best to review 680.42 as there are several stipulations.
 
Ah, thank you. I was not familiar with that change in the 2017 code. The panel we installed is on something like a post: it's a decorative cedar backboard supported on two cedar posts, built by the spa installation contractor.

I have reviewed 680.42 again and I believe this particular installation is in compliance, however I see there are several conditions it has to meet, so that perimeter bonding and #8 solid wire are not required.
 
Mr. Serious said:
Separate question, somewhat related: does a self-contained spa need to be bonded back to the panel serving it with #8 solid copper? I think it actually does not, but it would if it were built into the concrete like a pool, instead of self-contained.
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That #8 copper is for equipotential bonding. It doesn't have to go to anything not in the pool vicinity. The EGC in the branch circuit or feeder is sufficient for bonding to whatever is upstream in the electrical supply.
 
Mr. Serious said:
Ah, thank you. I was not familiar with that change in the 2017 code. The panel we installed is on something like a post: it's a decorative cedar backboard supported on two cedar posts, built by the spa installation contractor.

I have reviewed 680.42 again and I believe this particular installation is in compliance, however I see there are several conditions it has to meet, so that perimeter bonding and #8 solid wire are not required.
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Like the others said the equipotential bond. Which you refered to as a bond. It NEVER goes back to the panel. It does make condinuity through the eqipment grounding conductor of the pool eqipment.
You never want to install a bare #8 in a electric panel then run it around a pool. This equipotential bonding is attacched to the outside of the metallic equipment only in the pool area.
I don't claim to be a pool expert. I just find it interesting. (y) That Mysticpool guy, now he does alot of them.
 
Three people have told me the same thing here. So, point taken, when working with a pool or spa that requires #8 solid copper equipotential bonding, that bonding is extended all around the pool itself and to electrical equipment directly serving the pool area (pumps, lighting transformers), but does not and should not go back to the electrical panel.

However, in that case, it still will be bonded to the panel by means of the normal equipment grounding conductors that are run with the circuits serving the pool equipment. I don't really see a de-facto difference, except that those EGCs will typically be a little bit smaller. And we should keep them that way, because the objective is to solidly bond the pool area equipment, and NOT to provide extra bonding back to the power source.
 
One time I had a similar job and the inspector had us run the #8 into the GFCI that was powering the pump lol. I had to drill a hole in the exterior device box and then splice it to my #12 EGC. I guess all that matters is the size of the circuit when considering what goes back to the panel And the #8 is just keeping the different parts of the spa or pool at the same potential if a nut or bolt corrodes and breaks off. Does that make sense?
 
Yes, that makes sense to me, the #8 not only provides additional bonding around the pool area, but also provides a redundant bonding path in the case that the regular EGC fails. But the additional bonding around the pool area is most important: In your case with the pump receptacle, instead of having the extra resistance of the EGCs going to the panel and back to the pool, you have a #8 connected to it right there at the pool.
 
I know this is getting into the weeds and I apologize… When you’re talking about resistance this is with respect to lightning charging the ground right? The fault current still has to travel on the 12 EGC back to the panel to trip the breaker though, right? #8 isn’t doing anything to clear faults and if that #12 fails the #8 is also cut off from the GEC and could be at a different potential, right? That precious #12 could fail and cause an arc from the pool to the equipment connected to the house, couldn’t it?
 
Mr. Serious said:
Yes, that makes sense to me, the #8 not only provides additional bonding around the pool area, but also provides a redundant bonding path in the case that the regular EGC fails. But the additional bonding around the pool area is most important: In your case with the pump receptacle, instead of having the extra resistance of the EGCs going to the panel and back to the pool, you have a #8 connected to it right there at the pool.
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Doc13067 said:
I know this is getting into the weeds and I apologize… When you’re talking about resistance this is with respect to lightning charging the ground right? The fault current still has to travel on the 12 EGC back to the panel to trip the breaker though, right? #8 isn’t doing anything to clear faults and if that #12 fails the #8 is also cut off from the GEC and could be at a different potential, right? That precious #12 could fail and cause an arc from the pool to the equipment connected to the house, couldn’t it?
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The #8 bonding conductor is for "equipotential bonding". It is run to more than just electrical related items. Though it may help clear a fault if called upon to do so that is not it's intention. You want every metal object in a pool or spa to be bonded together to assure they are all at same potential. Packaged spas are slightly different game as they don't have as much earth contact with conductive shells and such, and there is lesser requirements involving them as a general rule. You do not want a pool user to come up to a metallic ladder, luminaire or other item that is even just a volt or two different in potential than the water they are immersed in - they likely are in danger if that happens. The entire equipotential bonding system could be operating several volts above earth voltage, but as long as there is no touch potential points within for users to contact they are still safe - similar to why nothing happens to a bird perched on a high voltage line.

Many cases a smaller conductor may be feasible to do the bonding, but I imagine they want a minimum of #8 for mechanical longevity reasons.
 
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