Rust from pool light ground wire

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Replacing the pvc conduit is out of the question as it goes under concrete. If replacing my spa light and pool light (the only 2 metal things under water in the pool) with low voltage lighting, negates the need to have the bonding wire connected, then I might consider that. But then, like Dirk, I'm confused of why it negates the code requirement. Bonding is supposed to protect from any electrical source that contacts the pool, not just the lights.

I've reached out to a few electricians and will report back.
 
Why a low impedance bond from a wet-niche luminaire to its forming shell and pool bonding grid reduces the risk of electric shock.

The equipment grounding conductor in the flexible cord of the wet-niche luminaire may be relatively small (as little as 16 AWG in accordance with the NEC), and may have a length of one hundred feet or more.

The relatively small AWG and long length will result in increased impedance through the flexible cord equipment grounding conductor.

If the electrical bond between the luminaire and the forming shell is poor or absent, in an electrical fault condition within the luminaire this increased flexible cord impedance causes a relatively greater voltage potential between the dead metal of the luminaire and other dead metal connected to the premises’ equipment grounding conductor.

The supplemental equipment grounding conductor in the form of corrosion resistant metallic conduit connected to the forming shell or the 8 AWG copper conductor routed with the flexible cord in nonmetallic conduit provides a second, more conductive, path for fault current originating in the luminaire.

https://www.ul.com/global/documents/offerings/perspectives/regulators/electrical/newsletters/swimpool0803.pdf
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Author’s Comment: The portion of the branch-circuit wiring to the pool junction box [680.23(F)(2)] shall contain a minimum 12 AWG insulated copper equipment grounding conductor.

The equipment grounding conductor between the pool junction box and the forming shell shall contain an 8 AWG insulated copper equipment grounding conductor [680.23(B)(1)].

A cord for a pool light run to the pool junction box shall have at least a 16 AWG equipment grounding conductor [680.23(B)(3)]. Figure 680-17 un680-17 680-23F2 02.cdr

Article 680 - Swimming Pool Installations
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Electricity gets complicated very quickly. That's why there's a code. Most people are not qualified to design safe electrical systems. Hopefully, the requirements in the code make sense and are not just annoying, expensive and useless.

I think that the wire is called a bonding jumper because it bonds the niche to the junction box but I think that the purpose is grounding. Both of the above references refer to the wire as an equipment grounding conductor (EGC).

This makes sense because the niche is already bonded and the junction box could be required to be bonded if that was the intention. And, bond wires are required to be solid, whereas the bonding jumper is allowed to be stranded.

Note: When you install a No. 6 or smaller EGC, the insulation along its entire length must be colored green or green with one or more yellow stripes. So, technically, the wire should be green even though it's not specified in the [680.23(B)(1)] section.

Listed low voltage lighting that doesn't require a ground is exempt because it doesn't need the ground.

The niche should still be bonded from the outside to the main bonding grid.

Maybe an electrician can come up with an acceptable answer that doesn't require an expensive repair.
 
Agree 100%, which is why I should stop contributing here, even if just posing questions, as I am certainly one of those not qualified...

Be sure your electrician is licensed, bonded and insured, checks out with the licensing agency (Texas Department of Licensing and Regulation) and can legitimately claim experience with wiring pools. All of which you must be aware, but can't hurt to remind...

Good luck. Please let us know what you eventually come up with.
 
The pool service now came up with an alternative solution that may work. They are going to install a light adapter repair ring, that has an integrated bonding lug connector, into the niche. That will allow us to re-connect the bonding jump wire. I'm still trying to get them to agree to pull off and replace the part of the connection that's rusting and covered in the white putty, but he thinks he can reconnect it as is and use a special underwater tape to seal in the rusty part of puttied connection. Otherwise, you have to drain the pool below the light level. Here's what I think is going to be used. Swimming Pool Light Repair Ring

James, Dirk - Thanks for your help on this.
 
Wow, looks to have been made just for your need! Too bad you can't get the proper goo on the connection. Maybe your contractor's solution will work well enough until you have some other reason to drop the water level.

From here (just a random google hit):

SSINA: Stainless Steel: Corrosion

The Statue of Liberty (completed in 1886) is one of the highest profile examples of the damage that galvanic corrosion can cause. The original design used a copper exterior skin (large cathodic or noble surface area) supported by a cast iron structural frame (small anodic or active surface area) with the metals separated by wool felt which eventually failed. In 1984, it was closed to the public due to significant corrosion of the cast iron frame. It was rebuilt using a duplex stainless steel structural frame. Copper alloys and stainless steels are quite close in the galvanic series with the duplex being more cathodic which is appropriate since it has the smaller surface area ratio.
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galvanic-series.jpg
 
I don't see any reason that they can't just cut off the bad part of the wire and strip off about 3/8" of insulation to expose new copper wire. That's the best way to get a good connection. There seems to be plenty of wire. No need to drop the water level. It should be easy to do under water.
 
JamesW said:
I don't see any reason that they can't just cut off the bad part of the wire and strip off about 3/8" of insulation to expose new copper wire. That's the best way to get a good connection. There seems to be plenty of wire. No need to drop the water level. It should be easy to do under water.
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I think maybe they're talking about how to get the "code compliant" goo to cover up the new connection, no? I was going to suggest the underwater epoxy stuff, but I suppose you wouldn't want to make that connection permanent, with epoxy? (For a $50 part, I would.)

Is there nothing else you can apply underwater that would do the job?

- - - Updated - - -

Wait, why can't they tie off the j-box end of the bond wire to something (another wire, rope, whatever), then pull enough of it out of the niche to get it above the water line. Make and seal and dry the connection to the new ring above water, then pull the wire back through the conduit to reconnect to the j-box. Put the ring into the niche after the bond wire is attached and sealed to it.
 
They did initially recommend to just cut off the connector and white blob stuff, strip a bit of insulation off and connect directly to the lug, as James suggested. But I thought the exposed wire would eventually corrode. He then did say he could cover it in epoxy. But I thought it would be easer to epoxy the white blob stuff. Dirk, good idea on the fishing approach. But now I'm thinking I can do option 1 & 2 myself.
 
Well, I managed to keep my ideas to myself about this problem for one whole day... even though I have not become an electrician in the interim!!

I would solder a new length of bond wire onto the old, about 1" worth to make a very strong connection, then pull the old one all the way out, feeding the new wire through (the new wire would be long enough for your purpose). A new wire should only be a few bucks, and this MO would mean much less chance of losing the end of the old one halfway down the conduit rabbit hole, pulling it out a bit, then pulling it back in, etc... That would not be a fun fix if you lose the end. Use plenty of lube (pool appropriate).

Or better yet, tell your electrician what you want done, then let him do it. If he loses the wire, then it's on him. And he'll likely have a better way of doing it than something I've never tried before!
 
You're not going to be able to get a good connection to the bonding lug without cutting off the old end. Even if you could, you would still need to use the potting compound to seal the connection. I don't see any reason not to cut off the end.

You should be able to tie a string to the wire at the junction box and then pull enough wire up to the deck so that you can make the connection and encapsulate the connection in the potting compound. Once the potting compound has set, you can pull the wire back to the junction box with the string.

It's in the code, so you have to use the potting compound. However, in my opinion, the potting compound makes no difference. If it worked, the end wouldn't have corroded off. In my opinion, the end corroded because it was probably brass. If it was copper or stainless steel, it would have been fine.

The end probably wasn't sealed completely, but I suspect that most don't get 100% sealed, anyway. Here's some more information that explains what the purpose of the wire is.

The insulated copper equipment grounding conductor required with rigid nonmetallic conduit is terminated at an approved grounding terminal in the junction box (or transformer enclosure) and at the inside terminal of the grounding/bonding terminal on the fixture's forming shell. This conductor has an equipment grounding function, not a bonding function. It's in addition to, and of a completely different function than, the No. 8 bonding conductor usually connected to the external bonding lug.

The bonding conductor, which must be solid, connects the forming shell to the common bonding grid, as required by Sec. 680-22(a) and (b). The No. 8 insulated copper equipment grounding conductor must be stranded, however. (Sec. 310-3 requires all No. 8 and larger conductors in raceway to be stranded.) The two exceptions given do not apply here. And it's important to also remember that Sec. 310-12(b) will normally require that the insulation be colored green.

Wiring wet-niche fixtures at the 1996 OLympics Aquatic Center. | Electrical Construction & Maintenance (EC&M) Magazine
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Wow, thanks James. So it's not a bond wire after all, is it? It's a ground. So that just raised 10 more questions, but they're academic. Code is code.

So my guess that it's extending the bond to the j-box was wrong. The j-box has to be beyond the 5' perimeter, right? So it doesn't have to be bonded? No matter, as you pointed out:

"Electricity gets complicated very quickly. That's why there's a code."
 
Locate junction boxes at least 4 inches above ground or pool deck level or at least 8 inches above maximum water level, whichever provides the higher elevation, and at least 4 feet from the pool or spa inside wall. If within 5 feet, it must be bonded.
 
If you look at the original pictures, there is a stainless steel terminal, still connected, to the wire that can be easily bolted to the ring. That’s why I wanted to just seal the potting compound section with an under water rubber tape. But I may just cut it out an attach the wire directly to the lug. Can you recommend an epoxy I can apply underwater?
 
Update: I jumped into the pool on Sunday ahead of the cold front. I cut the wire, installed the light ring, and bolted the fresh wire to the ring with a manual copper terminal. I couldn't seal it the potting compound, but I thought I would do that later, when I drain the pool due to high CH. Better to ground the niche now, I thought. Well, this morning I woke up to a large dark stain below the light (instead of above the light). It doesn't come off with the vitamin C in a sock trick, as it did before, it just gets darker. I'd jump in and take everything out, but the front came through and it's butt cold and raining hard. I don't know if it's coming from the ring because it isn't truly stainless steel (it looked too dull to be stainless), it was coated in something that is leaching off, or if there is something electrical going on. I'm super bummed, as I seem to have made the whole issue worse. Let me know if the characteristics of the stain point to anything.
 
I suspect that the stain might be copper or cheap steel.

If it is I would be concerned that you're getting some stray current. That could explain why the connector corroded off in the first place.

Stray current can be very difficult to track down. It might be a problem with the main house neutral.

If the main house neutral is compromised, current can travel through the ground from the source back to the grounded neutral at the transformer.

If you're comfortable working with electricity, you might want to check for voltage gradients around the pool between various bonding and grounding points.

One check that I would suggest is to open the junction box and disconnect the bonding jumper and light ground and check for voltage between the light ground wire and the ground wire going back to the light switch.

Don't do anything that you're not sure that you can do safely. If you aren't experienced with electricity, call an electrician.

You're going to have to pull the light back out to see what's causing the stain.

Pool Light Adapter Repair Ring by CMP is a Stainless Steel Frame that can be retrofitted into a light niche, to fix stripped or broken light mounts. It has 3 allen screws that anchor to the inside of the light niche, as well as a new bonding lug. Designed to easily detach ring for light cord, to install while light is still in the pool. It is the perfect solution for broken or stripped light nitches. Measures 10.5" diameter.
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The description says stainless steel. So, the mark seems odd. Definitely not a good sign.

The ring has a built in bonding lug, is that what you used to connect the bonding jumper?

Does the light work without tripping the gfci?

Have you tested the gfci recently by pressing the test button?
 
Thanks James. Light does work without tripping gfci. I did connect the bonding jumper to the bonding lug on the ring. I feel it has to be the cheap steel ring to make that much of a stain, so quickly, that sinks below the light. The wire had copper connectors before, and the stain was very slight and above the light and easily dissolved with vitamin c. I did realize that I could have bypassed the ring adaptor approach if I would have tried connecting the bonding jumper to the the light niche through the light mounting bolt hole at the front of the niche, using a good wire connector, stainless steel screw, washers, and nut. Then I can just rotate the light slightly to the right of the mounting hole and use a light wedge screw to hold the light in the niche. I'll have to rent a wet suit or heat the pool to get back in and try that.
 
Ok, I definitely understand how frustrating this is, especially when you're trying to do the right thing.

The main thing is that we want it to be safe.

Thanks for keeping us updated.
 
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