How to test my bonding.

[dradam]

I have been upgrading my load center to automation. Thank for all for your help here.

Original load center pro installed had a bonding wire attached to the loadcenter ground bus. It is my understanding that this is not necessary, but permissible. Bond could have gone to the outside shell only.

In repairing broken pvc to my pool light conduit I noted the 120v pool light comes to the above ground box with a hot, neutral and ground, but no bonding wire in the same conduit to the above groud (J? BOX). It then routes to a switched gfci in my home. I believe the below water light niche is brass. I must assume that the bonding wire to my panel bonds the pool and hopefully the light niche as well even though it is not going through the light cord conduit.

Can anyone recommend a way to test if the underwater niche is bonded to my bonding wire with out digging up behind it? If the light has a gfci is the code alone?

Thanks.

 

[JohnT]

The bonding wire wouldn't be in the conduit with the power wires. Normally the bond wire would route around the pool and often go from the dive stand to the light. Because of incidental grounding on electrical fixtures, it may be difficult to determine if the light housing is bonded. The easiest way may be to check for electrical continuity between things like ladder sockets, dive stand, rail sockets etc. and the pump bond wire as a check of how well they installed it. If they bonded everything else, they probably bonded the light.

 

[JasonLion]

Hum, my reading of code is different than JohnT's.

Line voltage lighting must be bonding to a metal light niche, both directly to the pool wall and in the conduit, unless the conduit is metal in which case the conduit it's self can be the bonding. Most low voltage lighting does not require bonding in the conduit, only to the pool wall and that only if they are made of metal.

It is possible to test this by measuring the resistance between the niche and the boding wire at the pump. The resistance should be less than 2 ohms. However, this will require a good quality multi-meter (as many of them loose precision at very low ohms) and a long heavy gauge cable for the return run while testing.

 

[dradam]

Thank you both for your reply. I have no access to the niche light from behind, only from the inside of the filled pool. There are no metal fittings around or in my pool. To test continuity to bonding can one take these measurements running a wire to the inside of the niche underwater? I would think a simple battery continuity tester would still work, or ohm meter. I.e wire attached to a screw that holds in the light to the niche and testing at the one bonding wire.

thanks

thanks

 

[JohnT]

The problem is that the light niche is going to be grounded, and so is the bond wire through the pump housing. That means they are connected even without the bond wire.

The bond wire is on the outside of the housing so the bond wire doesn't run in the conduit.

 

[dradam]

The only wire coming through the pvc conduit from my niche is the ground within the 120v light cord. Where else would it be grounded ? If it is grounded when the light is attached to the niche ( i.e ground attaches to the lights metal ring) would removing the light fron the niche unground it? or would it still reflect a ground conducted through the water in the pool? Very confusing. If it is in continuity with a ground in my load center isn't that really like bonding since the bonding wire is attached to the load center ground (even though it need not be). I understand that bonding is not grounding, but if the bond and ground are connected isn't it really the same potential throughout. many thanks.