Sanity check on pool light bonding

[Titanium]

I think I know the right answer, but I want to have some of the experts here look over my shoulder. I am replacing the complete light fixture in my attached spa with a match to the existing Pentair Amerlite pool light fixture. Before completing the project, I want to make sure that the electrical bonding to the stainless steel wet niche is proper and safe.

The above is a picture of the interior of the wet niche. There was a ton of plaster on the surface of the niche and this picture is after I chipped away most of it. Some of the plaster was literally 1/2 inch thick. There was no #8 copper bonding wire attached to the interior of the wet niche. The picture shows where the bonding wire would have landed. This bonding connection point was completely covered in plaster. The brass/copper bolt sheared off when I tried to remove it. My pool was built in 1983 and apparently used a brass conduit for the light conduit (which I understand has almost completely disappeared in lieu of PVC conduit in modern times).

My belief is that the spa light is properly bonded as it sits and that I do not have to pull a #8 copper bonding conductor when I pull the new light cable in the existing brass conduit.

Any thoughts or comments?

Titanium

 

[Belldiver]

Not an expert here but FYI...

I have the Pentair stainless steel light niches in my pool. They have bonding lugs on the inside AND outside of the niche. I only used the lugs on the outside of the niche so there is no visible bonding anymore. The #6 copper wire is now embedded in gunite.

The only thing I can think to do is test for electrical continuity from the bonding wire at your equipment pad to the metal of the light niche. Or, if in doubt, you could pull an additional wire through the conduit attached to the inside lug up to your equipment pad.

Jim

 

[Titanium]

Belldiver,

Thanks for the reply.

That was a good idea about checking for electrical continuity from the bonding wire at my equipment pad to the metal of the light niche. I made myself a long jumper wire (approx. 60 feet long) of #12 stranded copper and soldered a couple of alligator clips on the end. I only had 0.1 ohms when I tested just the jumper wire and alligator clips all by themselves, so I had a baseline of how much resistance the jumper wire/clip assembly had all by itself.

When I attached one clip of the jumper wire at the equipment pad bonding wire, and then connected my digital multimeter to the other end of the jumper wire and the metal of the light niche, I could not seem to get a stable reading. The readings seemed to bounce from a couple of ohms up to 40 ohms and then back down again. It was very strange. All I can really say is that I have some level of continuity in my bonding system between the light niche and the equipment pad.

I ended up choosing NOT to pull a separate green bonding wire with the cable for the light. My main reason was that the existing brass conduit appeared fairly small (1/2 inch ??) and I was afraid that pulling even the light cable alone was going to be difficult. It turned out, however, that the light cable pull was an absolute piece of cake. I was pulling on the string I had in the brass conduit up on deck at the junction box, while my seven year old son was in the drained spa helping feed the light cable into the brass conduit. And he evidently wasn't doing that much to feed the cable into the conduit as he later admitted.

In addition, even if I had pulled in a new bonding wire in the conduit, I still faced the prospect of trying to extract the broken bolt from the light niche bonding point. Although I suppose I could have attached the new bonding wire to the point where the light ring is bolted to the light niche.

The instructions that came with the Pentair Amerlight light fixture mentioned that a "Pool and Spa Electrical Qualfication Test Kit" is available so that "the pool or spa electrical system can be verified". I will do some research on this test kit in the morning.

Titanium

 

[Belldiver]

I wonder if the fact that the whole system is grounded is affecting a continuity test? Just a thought...again, not a true expert here.

 

[Titanium]

belldiver,

I would think that grounding, at worst, would provide additional parallel paths for the current to travel. This, if anything, would should reduce the resistance reading of the bonding path.

Titanium