Another Pool Question

[Davis Electrical]

I think there's a whole lot of obfuscation going on here. I asked specifically about a subpanel, not a branch ckt, or a multi-wire branch ckt, which we all know is impossible with a pool installation since GFIs do not permit us to share neutrals. The pool IS a separate structure and that structure includes the pump/ filter, which is inextricably linked through the pvc hosing which contains the pool water, that is a conductor. The pool "structure" includes the pool, the filter, even if separately housed, all associated decking, of whatever material, lighting, etc.

Not all swimming pools have steel walls, many are of concrete; that concrete contains rebar that may or may not directly contact the earth. Likewise the steel mesh utilized in concrete decking is generally encased in concrete; it does not directly contact the earth, and it is not intended as a grounding electrode. However, many pools DO have steel walls that directly contact the earth; while quality may therefore be a variable, the equipotential grid is in fact placed at earth potential.

The bird on a high-wire analogy is only an apt analogy under certain circumstances; it is not an apt analogy when I accidentally drop 120 volts into the pool, or in other words, when I inadvertently light up the water (which may or may not contain a bird). Are you following me here?

There are better ways to do this, better ways to ensure safety. We could for example create an additional safety device - multiple sensors - that monitor pool water potential.

I can remember the days when pools were still being wired in galvanized; PVC had not been invented yet. (Truth.) And either had the exponential grid. All of these things, including the grounding electrode of the separate structure are things that arrived piecemeal. In the case of the grounding electrode it was in an effort to reduce the induced voltages of type AC/ BX.

I hate to use these words but in reference to the grounding electrode of the pool structure, supplied by a feeder, "what difference does it make?" (I really hate those words.)

But electrical theory is not a gray area. If a ground rod is electrically required at a downstream separate "structure," then it is required at all downstream separate structures. And if not, we need to explain why. The "attached" by the way is only in reference to a subpanel contained within the same building. But even here you can see where this might be a problem.

You know, too, the NEC is only in force in certain locations. Many states have not adopted it and never will. It is more imperative that we "understand" than that we conform. And I'm not sure we've completely worked this one out.

 

[GoldDigger]

A two pole (240V) GFCI breaker can work just fine with the shared neutral of a properly wired MWBC. It just runs three wires through the current transformer instead of only two.

 

[iwire]

Moving away from it being one circuit or one multi wire circuit, If there are more than one circuit supplying the pool does it need a grounding electrode?

Moving even further down that road, how many branch circuits is a separate structure allowed?

 

[Dennis Alwon]

Like many here I struggle with applying the definition of structure to everything. I am not debating taking that approach base on the definition given for structure.

When a swimming pool is separated from the structure the pool panel is mounted to, is he incorrect for rising the issue? I am going to leave this to you guys, I really struggle with this and I do not have it settled in my mind.
maybe something needs to be added like with mobile homes or in site of or X amount of feet from

David, Firstly I don't think we are bashing him and if it comes across that way then I am sorry.

The issue to me, as I see what is being asked, is whether the pool panel, mounted to the structure it is fed from , needs a grounding electrode conductor. Although the pool may be a separate structure the panel is not mounted to it so no grounding electrode conductor is required. The pool may have a multiwire branch circuit going to it and it would not need a grounding electrode conductor. I am not sure what you would connect a grounding electrode conductor to if it were needed.

I wrote a proposal about septic pumps because they often have a 240v feed and a 120v alarm cir. I tried to get an exception in to 225.30 which requires only one feed to a structure. The cmp members said that it was a piece of equipment and thus it did not need to comply with 225.30. I still disagree however it shows that you can have more than one branch cir. to a structure without a panel. There is no physical way to mount a panel to a pool so I don't see how a panel would be required.

Not sure if this makes sense to anyone or not. Install that pool panel out in the yard off the dwelling it is fed from and yes a grounding electrode conductor is required.

 

[Little Bill]

Since I haven't done this in awhile, correct me if I'm wrong (and thus reeducate me): A pool subpanel requires a four wire install and a ground rod. Or two. ?

I'll try and give my simple answer to this question since it was what the OP asked to begin with.

Any sub panel requires a 4-wire feed. (Assuming single phase)

It depends on where the sub panel is installed as to whether it needs a ground rod (or any electrode).

Same structure as what it's fed from = no, no additional ground rod

Separate structure (another building, wooden post, strut asmy, etc) = yes, add rod (or any electrode)

Simply put, a sub panel for a pool is no different than any other sub panel in terms of the GES requirements.

 

[david]

David, Firstly I don't think we are bashing him and if it comes across that way then I am sorry.

The issue to me, as I see what is being asked, is whether the pool panel, mounted to the structure it is fed from , needs a grounding electrode conductor. Although the pool may be a separate structure the panel is not mounted to it so no grounding electrode conductor is required. The pool may have a multiwire branch circuit going to it and it would not need a grounding electrode conductor. I am not sure what you would connect a grounding electrode conductor to if it were needed.

I wrote a proposal about septic pumps because they often have a 240v feed and a 120v alarm cir. I tried to get an exception in to 225.30 which requires only one feed to a structure. The cmp members said that it was a piece of equipment and thus it did not need to comply with 225.30. I still disagree however it shows that you can have more than one branch cir. to a structure without a panel. There is no physical way to mount a panel to a pool so I don't see how a panel would be required.

Not sure if this makes sense to anyone or not. Install that pool panel out in the yard off the dwelling it is fed from and yes a grounding electrode conductor is required.

I agree and as I said I have a hard time defining everything as a separate structure when applying the rules associated with the NEC. In line with what you posted, some things are utilization equipment 680.12 Maintenance Disconnecting Means. ?shall be provided for all utilization equipment other than lighting? The article addresses separation by barriers and specifically addresses wiring underground and utility lines overhead. The article to me at least is treating the pool associated equipment as utilization equipment not a separate structure.

I also agree that a pool panel mounted on a building associated with the service location is a sub-panel and no grounding electrode would be required.

680.6 Grounding.
(7) Panelboards that are not part of the service equipment and that supply any electrical equipment associated with the specified body of water

680.25 Feeders. (2) Separate Buildings. A feeder to a separate building or structure shall be permitted to supply swimming pool equipment branch circuits,

680.25 calls out, ?swimming pool equipment branch circuits?, again indicating utilization equipment.

Ia swimming pool (structure) is dealt with using the parameters found in article 680.

 

[kwired]

I also agree NEC has some room for improvement on clarification of what is a separate structure in some cases. This gets complicated at times when we have two "structures" that supplement one another in some way. Should NEC consider them one structure or two when they supplement one another? NEC currently is not definite either way.

Most in ground pools - already have a concrete encased electrode so additional ground rods are not necessary anyway. A panel at a pool shed however will need a rod (or two) if there is no other electrode present.

Then you sometimes run into two completely separate buildings - build a covered walkway between them and somebody now wants to call them one building. Yet many fire and other building codes recognize a two hour finish as a suitable barrier to consider them separate buildings for applications of codes.

 

[david]

Separate structure (another building, wooden post, strut asmy, etc) = yes, add rod (or any electrode)

Simply put, a sub panel for a pool is no different than any other sub panel in terms of the GES requirements.

I agree that I would install and would want to see a panel as stated above supplying branch circuits for pool equipment utilize a grounding electrode.

First I am not sure such a panel installed could be claimed to have no other purpose than supplying pool associated equipment.

But if a panel served strictly pool equipment and i mean strictly not a building or landscape lighting or anything else, i mean strictly pool utilization equipment,

I think 680.6 makes that a little gray, since 680.6 specifically states that such a panel is considered grounded by using a wire methods in chapter 3 and the reference to article 250 specifically leaves out part III of article 250.

I am not advocating not providing a grounding electrode I just believe 680.6 as stated makes the requirement gray.

 

[Little Bill]

I agree that I would install and would want to see a panel as stated above supplying branch circuits for pool equipment utilize a grounding electrode.

First I am not sure such a panel installed could be claimed to have no other purpose than supplying pool associated equipment.

But if a panel served strictly pool equipment and i mean strictly not a building or landscape lighting or anything else, i mean strictly pool utilization equipment,

I think 680.6 makes that a little gray, since 680.6 specifically states that such a panel is considered grounded by using a wire methods in chapter 3 and the reference to article 250 specifically leaves out part III of article 250.

I am not advocating not providing a grounding electrode I just believe 680.6 as stated makes the requirement gray.

Maybe I am reading you wrong, but I didn't say not to use a GES. I said no additional electrodes were necessary if the subpanel is on the same structure/building as what feeds it.

As far as 680.6 leaving out section III. That section is for the GES. In parts V, VI, & VII, these are for bonding and the EGC. In order to comply with these, you would have had to comply with section III already.
I really don't see the "gray area".

 

[david]

Maybe I am reading you wrong, but I didn't say not to use a GES.

I really don't see the "gray area".

I didn?t say or think that you implied not to use a grounding electrode.

The gray area to me is if a grounding electrode is required at all for pool panel that are installed in a yard without any association with a building or any circuit not associated with the pool. If the feeder is supplying pool utilization equipment strictly than article 680 takes precedence over the installation.

680.6 calls out pool panels as one of the items covered under that section and seems to indicate that the equipment grounds and bonding associate with the chapter 3 wiring system satisfies any grounding concerns associated with that utilization equipment under that section.

By calling out just sections V , VI and VII of article 250 seems to support that equipment grounds are all that is needed to that equipment under that section for grounding purposes.

I would install a grounding electrode to a pool panel in the middle of a yard that supplies pool utilization equipment I am not sure one is required under article 680 and that is why I say requiring one may be a gray area. And I am not advocating not using a grounding electrode as stated.

 

[retire09]

I inspected pools in the Phoenix area for many years and most if not all have a sub panel mounted on the house, fence or separate support with circuits to the pumps, lights, heaters, etc associated with the pool.
All of the sub panels are fed with four wires with insulated ground in conduit from the house service panel.
I have been away from pool inspections for a long time now but I do not recall ever seeing a sub panel with its own electrode system.
Thousands of pools have been done in the Phoenix area this way.

 

[kwired]

I have searched (not too hard) and have not found any definition of or occurrence of the term "pool panel" in the NEC.

There is 680.25(B)(2) which says "A feeder to a separate building or structure shall be permitted to supply swimming pool equipment branch circuits, or feeders supplying swimming pool equipment branch circuits, if the grounding arrangements in the separate building meet the requirements in 250.32(B)"

250.32 is the general rules for "Buildings or Structures Supplied by a Feeder(s) or Branch Circuit(s)".

Call the pool a separate structure if you want, but does anybody ever feed the "pool" with a feeder? Do you put a panelboard on a pool? I will not say it is never done, but usually you are feeding the "pool" with branch circuits. That said 250.32 applies to branch circuits to separate structures as well. This still leads us to the somewhat unclear distinction of when is separate items considered separate structures, and when are they supplemental to one another and for code purposes considered part of the same structure? I don't think this has ever been all that clear. Take an industrial type application where you maybe have a storage tank, hopper, bin, etc. that holds bulk material that is really a separate structure to the building where the stored material is used. Inside that building you may have controls, multiple circuits, etc that run to this separate structure to handle things like adding material, taking material away, agitating , cooling, heating or other maintenance/treatment of the contained product or even just monitoring the amount of material or it's condition in there.

It gets more difficult to do all this if you call that a separate structure and only allow a single feeder as required by parts of art 225. A pool is similar. About only things that have power directly run to them are underwater lighting or a chair lift. Pumps, heaters, and other similar equipment is typically not a part of the pool but rather an accessory that is somewhat remote from the pool. The lights are generally considered a part of the pool, but a chair lift could itself be called a separate structure with a real general definition of "separate structure".

 

[david]

I have searched (not too hard) and have not found any definition of or occurrence of the term "pool panel" in the NEC.

680.25 Feeders. (B) Grounding. An equipment grounding conductor shall be installed with the feeder conductors between the grounding terminal of the pool equipment panelboard and the grounding terminal of the applicable service

I should have used the term pool equipment panelboard insted of pool panel

 

[kwired]

680.25 Feeders. (B) Grounding. An equipment grounding conductor shall be installed with the feeder conductors between the grounding terminal of the pool equipment panelboard and the grounding terminal of the applicable service

I should have used the term pool equipment panelboard insted of pool panel

I did read that but never commented on it. It is still not a code defined term, and besides that section is about equipment grounding not grounding electrode system.

 

[david]

I did read that but never commented on it. It is still not a code defined term, and besides that section is about equipment grounding not grounding electrode system.

And I think equipment grounding is exactly my train of thought article 680 addresses pool equipment feeders (panelboards) and nowhere in article 680 is a grounding electrode required for that feeder (panelboard) no mater where it is installed, in a field or in a residential yard, on a building or in a building. The OP asked if a pool sub-panel had to have a grounding electrode and the answer in my opinion is no.

And since article 680 said no it does not matter if the pool is a separate structure or not, as long as that structure is just a swimming pool and equipment associated with the pool.
that takes me back to 680.6

Then you have a permissive rule since you are not required to install a pool equipment feeder (panelboard) you can feed the equipment associated with a pool from some other feeder (panel) installed for some other purpose as long as that feeder meets the requirements in 680.25B

 

[augie47]

On the other hand, take the pool out of the picture. Go 100 ft from the house, build a wall or rack, mount a panelboard and a time clock on it to feed some
lighting and a well pump.
By NEC definition, is the wall/rack you built a structure ?
If you answer yes, then a grounding electrode is needed.

 

[david]

On the other hand, take the pool out of the picture. Go 100 ft from the house, build a wall or rack, mount a panelboard and a time clock on it to feed some
lighting and a well pump.
By NEC definition, is the wall/rack you built a structure ?
If you answer yes, then a grounding electrode is needed.

Agreed,

and that is why I am not advocating excluding the grounding electrode for pool equipment panelboards installed in a similar location as you describe and that is why I would install one.

 

[Little Bill]

On the other hand, take the pool out of the picture. Go 100 ft from the house, build a wall or rack, mount a panelboard and a time clock on it to feed some
lighting and a well pump.
By NEC definition, is the wall/rack you built a structure ?
If you answer yes, then a grounding electrode is needed.

Agreed,

and that is why I am not advocating excluding the grounding electrode for pool equipment panelboards installed in a similar location as you describe and that is why I would install one.

I said this in a previous post in this thread.

As far as 680.6 leaving out section III. That section is for the GES. In parts V, VI, & VII, these are for bonding and the EGC. In order to comply with these, you would have had to comply with section III already.
I really don't see the "gray area".

I say again, if you comply with the requirements listed in V,VI, & VII, you would have had to already have a GES in place as III describes if you ran from an existing (legally installed) panel. Or if you add a panel to a different building/structure you have to add a GES.

 

[david]

I said this in a previous post in this thread.



I say again, if you comply with the requirements listed in V,VI, & VII, you would have had to already have a GES in place as III describes if you ran from an existing (legally installed) panel. Or if you add a panel to a different building/structure you have to add a GES.

Service ---------feeder --------------separate building/panel --------------- pool equipment branch circuit
Service ---------feeder --------------separate structure/panel --------------- pool equipment branch circuit


Service -------feeder --------separate building/panel -------(pool equipment feeder/panel)------- pool equipment branch circuit

Service -------feeder -------separate structure/panel -------(pool equipment feeder/panel)------- pool equipment branch circuit

(2) Separate Buildings. A feeder to a separate building or structure shall be permitted to supply swimming pool equipment branch circuits, or feeders supplying swimming pool equipment branch circuits, if the grounding arrangements in the separate building meet the requirements in 250.32(B). Where installed in other than existing feeders covered in 680.25(A), Exception, a separate equipment grounding conductor shall be an insulated conductor.

if the grounding arrangements in the separate building meet the requirements in 250.32(B).

280,25 only requires an equipment ground to swimming pool equipment feeders, the section indicates that the pool equipment feeder originates from the separate structure feeder and the swimming pool equipment feeder with an insulated equipment ground continues to pool equipment branch circuits.

When you mount your pool equipment panel and want to call that a separate structure that is up to you. I see article 680 calling that equipment with the pool equipment feeder for pool associated equipment.

If you want to also feed branch circuits for some other utilization equipment that takes you out from the umbrella of pool utilization equipment and that opens you up to all kinds of interpretations as to the unistrut , 4X4 or you may have to mount the panel to a large bolder to not be classified by definition a separate structure.

 

[Davis Electrical]

I have searched (not too hard) and have not found any definition of or occurrence of the term "pool panel" in the NEC.

There is 680.25(B)(2) which says "A feeder to a separate building or structure shall be permitted to supply swimming pool equipment branch circuits, or feeders supplying swimming pool equipment branch circuits, if the grounding arrangements in the separate building meet the requirements in 250.32(B)"

250.32 is the general rules for "Buildings or Structures Supplied by a Feeder(s) or Branch Circuit(s)".

Call the pool a separate structure if you want, but does anybody ever feed the "pool" with a feeder? Do you put a panelboard on a pool? I will not say it is never done, but usually you are feeding the "pool" with branch circuits. That said 250.32 applies to branch circuits to separate structures as well. This still leads us to the somewhat unclear distinction of when is separate items considered separate structures, and when are they supplemental to one another and for code purposes considered part of the same structure? I don't think this has ever been all that clear. Take an industrial type application where you maybe have a storage tank, hopper, bin, etc. that holds bulk material that is really a separate structure to the building where the stored material is used. Inside that building you may have controls, multiple circuits, etc that run to this separate structure to handle things like adding material, taking material away, agitating , cooling, heating or other maintenance/treatment of the contained product or even just monitoring the amount of material or it's condition in there.

It gets more difficult to do all this if you call that a separate structure and only allow a single feeder as required by parts of art 225. A pool is similar. About only things that have power directly run to them are underwater lighting or a chair lift. Pumps, heaters, and other similar equipment is typically not a part of the pool but rather an accessory that is somewhat remote from the pool. The lights are generally considered a part of the pool, but a chair lift could itself be called a separate structure with a real general definition of "separate structure".

Again I think you're all obfuscating all over the place here: 250.32 (A) specifies a grounding electrode or grounding electrode system, except in the case of a single branch circuit. 250.32 (A) states that the grounding electrode conductors shall be installed in accordance with 250.32 (B) or (C).

I'm saying a pool is a "structure"; it requires a grounding electrode or grounding electrode system AT the structure, which must be wired in accordance with 250.32 (B). No where in 32 (B) does it suggest we can eliminate that grounding electrode system; in fact, it uses the word "and" to signify its existence, as in: "and to the grounding electrodes."

End of story.

Not really because I have no intention of installing the ground rod either. In fact I find it a little redundant even in the case of an actual structure. My point is that we've been playing these games since the 60s and it's time we focused on getting the NEC right.