AG Pool wiring and other headaches

[The Raddish]

For pool equipment wiring, 6 inches is the required depth for metal conduit, and 18 inches for non-metallic conduit. 680 does not make the exception for GFI. Although your 12 inch depth may meet article 300, it is in violation of 680.

While I don't currently have it in front of me, I could have sworn that I read something to this effect in 680:

"The nonmetallic conduit must be buried a minimum of 12” deep if 120 volt GFI protected from the start of the branch circuit. All nonmetallic conduit must be at least 18” deep, if not GFI protected."

In fact, this site has been pretty helpful in understanding the NEC section 680, and he points out this burial depth two or three times.

Either way, the conduit is all in place now, I need only wire the circuit at this point. I'm also not worried about passing any kind of inspection (since I'm out in the county and it is a previously installed pool, I don't need a permit), I'm mainly concerned with safety for me and my family. The previous wiring job was a death trap, literally. What I have replaced it with may not be 100% to code, but it is safe, and that's the important thing to me.

In a comment above, another poster stated that you shouldn't bond a double insulated pump motor. Per NEC 2005, the bonding wire must be installed, just not connected to the motor in the event a replacement motor is installed that requires bonding. These are primarily above ground pumps.

I saw that, and it got me to wondering: where would be the bonding point on this circuit, if not on the pump motor housing?

- 1: I don't have a "fill table" handy, but I think you -might- have too many wires in that 3/4 conduit. Double check the allowable fill for conduit.

-2: Instead of standard elbows on the conduit, you can/should use pulling elbows. It also -might- be required to use pulling elbows. Again, I don't have the tables/code handy to look it up.

- 3: Use wire pulling lube aka "snot".

1- I'm under 40% fill. I don't have the numbers here, but I'm fine.

2- Conduit is already assembled and buried at this point. Since I've only got two 90º standard radius turns, I should be okay. Last night I tried taping the wires together and pulling/pushing them through, but I made the mistake of not staggering the wires when I taped them.

I'll pick up some lube today or tomorrow and try again, this time with a few changes. One, I'll stagger the wires to make negotiating the bends in the conduit easier, and two, I'll use some heavier nylon cord instead of the thin twine that I was trying to use last night (which was getting me nowhere). The lube should help, too.

Again, thanks everyone for your input in this thread. Not only has it helped me, but I'm sure it has helped more than a couple of lurkers out there, too.

[JohnT]

I saw that, and it got me to wondering: where would be the bonding point on this circuit, if not on the pump motor housing?

There is no bonding point. You just tie everything together. No ground is used, so the grounding that occurs via the pump motor housing is incidental.

[The Raddish]

Okay, I think I have been getting bonding and grounding confused.

My pump will be located about eight feet from the pool. Everything that is bonded is supposed to be within five feet of the pool. The only metallic body greater than 4" square within five feet of my pool is the pool itself. Does this mean that bonding isn't necessary, unless I am to bond the different metal parts of the pool to itself? I also understand that the 8AWG wire should be run to the area of the pool pump in case a non-double insulated pump is every installed.

Also, I keep reading that an earth ground rod is not desirable on a pool circuit, and I am baffled as to why that is the case. This seems to imply that any grounding that takes place is to do so through the residence grounding system. Is this correct?

[JohnT]

Okay, I think I have been getting bonding and grounding confused.

You are not alone. Most electricians and pool installers don't get it either.

My pump will be located about eight feet from the pool. Everything that is bonded is supposed to be within five feet of the pool. The only metallic body greater than 4" square within five feet of my pool is the pool itself. Does this mean that bonding isn't necessary, unless I am to bond the different metal parts of the pool to itself?

That is exactly what you do: bond all of the metal pieces together so none can be at a different voltage. You also have to bond any conductive part of electrical equipment that could or does contact the pool water even if not within 5 feet. That would be some pump motors, heaters, SWCs etc..

Also, I keep reading that an earth ground rod is not desirable on a pool circuit, and I am baffled as to why that is the case. This seems to imply that any grounding that takes place is to do so through the residence grounding system. Is this correct?

By pool circuit, do you mean the power circuit for the pool? If so, it is bad practice to ground an electrical system at more than one point. You wind up with current flowing through the earth. Voltage is different at different points, so if you tie them together with a ground system, weird things happen. If you mean the bonding system, the idea is to create that "equipotential plane" which means anything the swimmer can touch is at one voltage. It doesn't matter if that voltage is the same as your house power, because any voltage without a reference is just an arbitrary number. If there is one thing conductive that a swimmer can touch that is at a different potential, then they can be shocked. Grounding just doesn't enter the equation. Adding a ground rod can make the whole mess subject to stray voltage problems. There was a FPN (Fine Print Note) added to the 2005 Code stating "equipotential stray voltage bonding conductors aren't required to extend to any panelboard, service equipment, or an electrode."

You really need to refer to the 2005 NEC. It explains some of this much more clearly than 2002. You may also want to Google for 2008 proposals for 680, as there is more change coming.

Look at Table 680.10 for burial depths. Clearly 18" min inside the 5 foot area.

[The Raddish]

By pool circuit, do you mean the power circuit for the pool? If so, it is bad practice to ground an electrical system at more than one point. You wind up with current flowing through the earth.

As an EE, I understand ground loops. During this whole process I've been trying to bring my EE knowledge with me. I'm not an electrician, but I have done more than a few wiring projects at home. This is the first time I've ever been confused, and I think it is more terminology than anything. Your explanation of bonding in your above post i think cleared up the muddied waters for me.

Getting back to the grounding rod issue, is a grounding rod required at the breaker box for the pool (which is a separate box from the house, but fed from the house box)? I had to return the copy of the 2002 NEC that I had borrowed from a friend, so I don't have access to it any more. I seem to have read conflicting info on the grounding rod for the pool breaker box.

Look at Table 680.10 for burial depths. Clearly 18" min inside the 5 foot area.

All of my underground conduit is greater than 10' away from the edge of the pool. It is nonmetallic, buried at about 14". Everything closer is above ground, attached to the deck structural members.

[robot9000]

There is no bonding point. You just tie everything together. No ground is used, so the grounding that occurs via the pump motor housing is incidental.

Hi All, I'm in the beginning stages of building my AG pool. I too was a bit confused about the bonding thing. I think eveyone thinks of 'ground' as the magic bullet. "Here's your problem - you didn't ground it !"

Really, you are just tying everything the swimmer might touch that is metal to be at the same potential, which brings me to my comment/question.

I have no metal fence or anything within 15 ft of my pool. My pump is double insulated, so I really just need to bond the uprights/foot plates with the proper wire and have it long enough to reach my pump in case it was replaced with one not double insulated. Is that correct in a nutshell? No attaching it to a ground rod. No attaching it to the pump ckt ground. Just make use all the pool parts and anything metal around the pool is electrically connected.

Also, in my city, the code is for metal conduit to be at least 6in and non metal conduit to be at least 18 in buried.
Thanks !!

[JohnT]

I really just need to bond the uprights/foot plates with the proper wire and have it long enough to reach my pump in case it was replaced with one not double insulated. Is that correct in a nutshell? No attaching it to a ground rod. No attaching it to the pump ckt ground. Just make use all the pool parts and anything metal around the pool is electrically connected.

Yes, that is correct.

[haze_1956]

I thought I was following this but those last few posts got me reconfused.

Is this right ?

Bonding - Connecting a number of metal objects so they will have a common electrical potential, but not to be grounded.

If this is correct, wouldn't the metal housing of a double insulated pump still have to be bonded, if within a set distance from pool?

[JohnT]

I thought I was following this but those last few posts got me reconfused.

Is this right ?

Bonding - Connecting a number of metal objects so they will have a common electrical potential, but not to be grounded.

If this is correct, wouldn't the metal housing of a double insulated pump still have to be bonded, if within a set distance from pool?

Double insulated pump motors are specifically exempted from bonding in the NEC. In order for a pump to be labelled "double-insulated", it must be tested and evaluated for this when it is tested by UL or other certifying organization. Small items are generally considered exempt from bonding requirements if it is unlikely they could become energized.

[denanbob]

My DH just got done sledgehammering 10ft copper rods into the ground at six different points around our pool. I don't even know HOW we would begin to get those out. We searching for how to ground a pool and this is what we found. Now I'm finding out this may not be the case. He also put little copper connectors at the base of each of our posts/pillars that hold the pool up. He then is threading #6 copper wire through each connector and ground all the way around the pool. So it will go connector/ground rod/connector/ground rod, etc................Please tell me we don't have to rip this all out. If anything, is it just overkill?