Bonding and Pool Pumps and Lighting
Not sure this was brought up before (I came in late), but I wired up my pool 4 years ago and spent a lot of time sorting out the codes.
One issue that has not been mentioned: if your pool pump is double insulated (most likely is), the bonding wire should not be attached to it.
(Yet the 2002 code says you should still keep in nearby just in case some day someone else installs a non-insulated pump ...)
I found the following web site useful:
http://www.selfhelpandmore.com/homew...bove/index.htm
And confirmed most of it myself with the 2002 NEC (I'm a EE PE, though I don't use the PE much for a living -- sorting out the pool stuff is the most code-intensive thing I've done)
Another issue regarding pool lighting:
The code for underwater lighting is really specific. Like requiring that conduit is run all the way to the box (not just the house), and that the circuit is not shared with anything else except pool lighting. It is by far the most underutilized 15A circuit in my entire house (just one AG pool light).
Re: AG Pool wiring and other headaches
Quote:
Originally Posted by prh129
OK - I see where that is defined in section 300.5. I will have a GFI breaker on the circuit so I would be covered in that case with a 12" depth but I'm not sure it meets with part 680.10.
It is not clear to me if the depths listed in 680.10 apply only to non-pool wiring that can't be moved away from the pool area or if it's for all wiring in the pool area. I'd like to know up front in case it becomes an issue at inspection time.
John T - you seem to have experience with this - what do you know about this?
Thanks
Peter
Peter, the first thing you need to be aware of is that local codes are often more strict than NEC, and sometimes have pretty unexpected requirements. Often, cities have a handout that outlines local codes. Also be aware that there are changes regarding pools in every revision of the NEC, and 2005 had many. These changes are mostly clarifications, because this stuff is confusing, and many electricians and inspectors don't understand it. Even if you are NEC 2005 to the letter, you may not be in compliance with local codes.
680 says no wiring with 5ft of the inside of the pool wall except for pool equipment feeds unless space or property lines make it necessary. 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.
It is my understanding that this requirement applies to all wiring in the pool area, even if it is not pool related and allowed by the space exception. Also, utility companies do not conform to NEC, but rather have their own code (NESC). If this affects you, contact your power company.
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.
Re: AG Pool wiring and other headaches
Thanks John. I dug the trench and buried the conduit last fall so I could plant grass. The electrician is pulling the permit, installing the bonding wire and making all of the connections so the only thing I have to worry about is the conduit depth. At worst case, I'll just have to dig it up and bury it a little deeper (and hope I don't hit any huge rocks).
Peter
Re: Pulling wire through conduit...
Raddish,
Regarding pulling your wire through the conduit, three things come to mind right away:
- 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".
Re: AG Pool wiring and other headaches
Quote:
Originally Posted by JohnT
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.
Quote:
Originally Posted by JohnT
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?
Quote:
Originally Posted by Mike_in_NJ
- 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.
Re: AG Pool wiring and other headaches
Quote:
Originally Posted by The Raddish
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.
Re: AG Pool wiring and other headaches
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?
Re: AG Pool wiring and other headaches
Quote:
Originally Posted by The Raddish
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.
Quote:
Originally Posted by The Raddish
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..
Quote:
Originally Posted by The Raddish
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.
Re: AG Pool wiring and other headaches
Quote:
Originally Posted by JohnT
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.
Quote:
Originally Posted by JohnT
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.
Re: AG Pool wiring and other headaches
Quote:
Originally Posted by JohnT
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 !" :D
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 !!
