Bonding wire not found on equipment pad

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CraigMW

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May 19, 2011
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Orange County, CA
I am in the process of planning to do an equipment upgrade of our pool. We bought our house about 2 years ago, and it's been running fine, but we'd like to change out the WhisperFlo filter pump to a new Pentair variable speed pump (e.g. the new one that ends with "18" in the product number. I believe the pool may be over 20 years old (the house was built in the late 60's), but the equipment was changed about ten years ago (based on what is there). When the equipment was changed, they did not apparently attach the bonding wire from the pool shell to the pump or heater, and I cannot locate it. Also, the two color changing SAM lights do not appear to contain bonding wires, only grounding wires (these are both 120V lights). Fortunately, nobody has experienced any sensation of electrical flow in the pool (perhaps because all of the plumbing in the pool is sch 80 2" piping).

Thus, my question is how I should proceed? I will try to dig around the equipment pad and see if I can find the bonding wire. But, if that fails, I guess I'd have to come up with some way of re-bonding the pool. I believe both of the pool niches are from Pentair/Amerilite, and those should have internal and external bonding lugs. Would it be sufficient to run bonding wires via the lighting conduit (sch 80 PVC unfortunately) to those bonding lugs, and then run the 8 ga copper bonding wire back through the conduit to the pool light box, and then to the equipment pad? Would it be necessary to have to dig up parts of the concrete deck to add bonding wires to the re-bar (this is a concrete/plaster pool)? I'm really frustrated because the guy who lived here before seemed to do plenty of wiring but didn't seem to understand the concept of proper grounding and bonding. Any sense of how expensive this might be to hire a professional?
 
I may be completely off base here, but I know in my area, the bonding issue was non-existent till about 10 years ago. Could it be that the current standards for bonding were not in place in your area when the upgrade was made? I am sure they were not in place when the pool was built, though I'm not sure of the specifics of when the NEC changed.
 
I wouldn't spend too much time digging and looking. Most likely it was never done. I'd just plan on running a new bonding loop whichever way is easiest to do it. You may not be able to meet the full code requirement but close is better than nothing.
 
Is the bonding loop necessary on a plaster pool? Doesn't the cement basically act a a 'bond' to the earth?

As far as your heater and pumps go, drive a copper rod into the ground and attach a #8 bare copper wire to the rod and your equipment. The niches should be bonded to the junction box that is probably 18" above ground. Inside is usually a ground/bond lug where the load ground, service ground, and bond wire attach.

Doug
 
douglee25 said:
Is the bonding look necessary on a plaster pool? Doesn't the cement basically act a a 'bond' to the earth?
Click to expand...
Code requires connecting any reinforcing steel to the bonding system and also running a loop around the pool.

You are talking about grounding, which is not at all the same as bonding and is not at all sufficient. There is no need for a grounding rod, nor is it desirable. The rebar in the concrete and the bonding lugs on the equipment need to be connected by #8 bare copper wire so that everything is at the same potential.

The challenging part is finding and making a good connection to the rebar in the concrete, if there even is any. Often you can break off some concrete and find either rebar or a wire grid, but that makes a mess and usually results in a visible patch.
 
I do understand the meaning of bonding vs. grounding, but years ago the NEC never asked for the pool itself to be bonded. Before I believe it was just pool equipment to be bonded. I am surmising that maybe his pool never had one - hence the 'is it necessary' at this point question. Maybe I shouldn't have said 'earth' but in essence, the earth is the grid so to speak.

So if you do feel it's necessary for him to have the pool bonded because he doesn't have one originally, how can he install it at this point?

Edit: And the other thing that confuses me is the fact that some/most say bonding systems aren't supposed to be tied into the ground systems. Well on the junction box for pool lights, the ground buss and bond lug are the same thing?

Doug
 
Bonding is often/usually connected to ground somewhere, but you want to minimize the number of places where that happens, or you can create ground loops. Ground loops can cause corrosion and in extremely rare cases create worse problems.

Connecting something to ground is nothing like connecting it to the bonding system. Ground connections are going to have some huge number of ohms, bonding is going to have a fraction of an ohm. That kind of difference makes all the difference in terms of safety (in the very rare situation there is a problem).

Grounding is done for entirely different reasons, which are already taken care of by the electrical system ground.

The existing concrete might not have any metal in it. In which case there is nothing at all simple you can do. But older concrete almost always used rebar, so chances are there is metal and attaching to it will improve the situation. How much work one wants to do that do that is debatable. There are advantages to doing things right, or as close to right as can reasonably be managed. So really it becomes a judgment call about what is a reasonable effort to take given the available budget, etc.
 
I checked out the NEC 2011 book because this topic struck my interest. My pool is at least 10-12 years old (done by previous owner). A few things I've noticed on my own personal pool and spa.... 1. There are bonding wires from the two pump motors that go into the ground (they are not 8ga though - smaller I believe). 2. The gas heater is not bonded. 3. The wet niche for the pool and the wet niche for the spa are both bonded. 4. I have no idea if the pool itself is bonded.

The NEC book does not really cover existing installations. Refer to section 680.26. What has been said here is basically correct. A concerte pool itself needs to be bonded via an 8 ga bare copper wire in a minimum of 4 points (I believe I interpreted this correctly) because concrete is considered to be a porous surface. The pool equipment (heater, pumps, wet niches) can be connected to this bond loop. If the pool is fiberglass or a liner pool, it is not subjected to the same bonding requirements.

Doug

Edit - I'm going to edit this post. I went out and checked my equipment. It appears I do have a properly bonded pool. I guess I never noticed but there is in fact a wire coming out of the ground that goes towards the pool.

Editx2 - I checked with an multimeter today and sure enough, the wire coming out of the ground is a bonding wire. I checked the wire against the light junction box. Good to know.
 
Wow, thanks for all of the recommendations. I will dig around a bit more to see if I can locate any bonding wires that may have been buried during the last motor replacement. It may be correct that the NEC didn't require bonding at that point, but I don't think so, as this would have been around 2003 or so (based on the age of the equipment). Instead, the folks who did replace the original equipment may have just neglected to run any bonding wire. In this case, I think I should be able to run bonding wire to the wet niches where I believe there should (hopefully) be bonding lugs. I really don't want to have to rip up concrete to get to the rebar in the pool, and if the pool was at one point bonded, then they would have run bonding wire between the rebar to the wet niches.

Regarding grounding vs. bonding, I somewhat understand the point of it. Electrical ground is designed as a high conductive path to ground in case of equipment failure (e.g. shorting of a hot wire to a metal case, etc). Bonding is supposed to tie together all metallic equipment (and now in the 2011 NEC) and water in the pool so there can be no stray potential difference that might shock a swimmer. There are a couple of things I don't understand with this (and apparently, I'm not alone based on some of the responses). First, isn't the bonding itself just attached to ground? After all, the pool is wrapped all about with a rebar mesh, and the bonding wires are supposed to be uninsulated 8ga (or greater) copper wire direct buried. Given this contact with earth, this would be quite similar to just driving a large ground rod into the earth, except that it surrounds all sides of the water (and also should be connecting to other metal parts near the pool (e.g. pool fences, light niches, etc)? Of greater concern, what would happen if there were equipment failure in either a pool pump or heater such that one of the 220V lines contacted the case of the unit. That case is bonded directly to the outlying mesh of the pool rebar. Now we have 120V stray voltage in the water, and anything unbonded (say due to rusting over several years) now becomes a path to ground. It would seem this could easily kill someone, as opposed to minor voltage differences that might exist without bonding.

Any EE's here to explain this to us?

Again, thanks for all of the help here! You all are great!
 

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Bonding connects everything that a swimmer could possibly touch together so it is all at the same voltage/potential. If every single thing you are touching is directly connected to a 230 volt live wire (or 1,000 volts, or 1,000,000 volts) you are still fine because there isn't any voltage difference, so no current flows. You are only at risk if you are touching things that are at different voltages/potentials. You start to have problems when there is something connected to the water, or close enough that you could touch it, that is not connected to the bonding system. That is why it is so important to bond everything metal/conductive.

The bonding system is only incidentally connected to ground. What that means is that it doesn't really matter if the bonding system is connected to ground or not. It only matters that everything you can touch be bonded.

If a 230 volt line touches the bonding system you will trip the circuit breaker. The easiest way for things to get dangerous is if an extension cord falls in the middle of the water and does not touch the bonding system. Then current is flowing from the cord, through the water, to ground. That current would quite possibly not be enough to trip the breaker but still be enough to kill you. There are lots of rules intended to keep wires away from the pool, in an attempt to prevent that from ever happening.
 
Okay, I think that makes more sense. As long as EVERYTHING is at the same potential, it should all be okay. Fortunately, we don't have any metal parts in the pool, only the stainless lighting bezels. But, given the surrounding rebar mesh, I guess this could be a source of potential difference. I sure hope I can find an easy way to tie that in.

Thanks again!
 
Just because I'm interested in the topic . .. The following leads me to believe the NEC change was 2005. Which seems right according to my recollection of conversations with an electrician friend.

http://www.nciaei.org/section/pdfs/SwimPoolGrid.pdf

If your equipment upgrade was 2003, it preceded the NEC change. And because some jurisdictions don't immediately adopt changes to the NEC into their local codes, it could have been several years before the bonding change impacted all jurisdictions in the country. For instance, my local jurisdiction follows the NEC, but not the most recent version.
 
Also, for anyone who is interested, CMI (Consolidated Manufacturing International) makes some pretty good stuff in regards to equipotential pool bonding. If you click on the left hand side 'Pool and Spa Electrical' you can see some pictures and even look at their catalog. They have bonding grids for walkways, directing bonding means for pool water, and other associated hardware. Good stuff.

http://www.cmiwebsite.com/index.html

Doug
 
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