Wet niche

[guschash]

I have question on bonding the wet niche housing. I know you bond the terminal on the outside of the niche for both low voltage and high voltage but if the housing is all pvc is it necessary to bond the terminal on the inside if its 120v. Inpector told a client that its not necessary . I don't see that in the bonding section. Is something new , I'm using the 2014 code book. Thanks

 

[Dennis Alwon]

If everything is plastic then what is there to bond. The actual light itself will have an equipment grounding conductor in the cord.

 

[guschash]

Most wet niches have a bonding terminal on the outside and right on the inside is a terminal to bond should light be 120 volts. Atricle 680.23(B)(1)(2) and explanation Wet-Niche luminaries. It says this conductor serves as the path for ground-fault current in the event of a ground fault when the wet-niche luminaire is removed from the forming shell, which is typically done during relamping.

 

[Dennis Alwon]

Most wet niches have a bonding terminal on the outside and right on the inside is a terminal to bond should light be 120 volts. Atricle 680.23(B)(1)(2) and explanation Wet-Niche luminaries. It says this conductor serves as the path for ground-fault current in the event of a ground fault when the wet-niche luminaire is removed from the forming shell, which is typically done during relamping.

Are you sure there is a bonding screw on the plastic shell? What is it attached to? If there is one then it makes no sense other then some inspectors wanted to see one so the manufacture put it there

 

[curt swartz]

Are you sure there is a bonding screw on the plastic shell? What is it attached to? If there is one then it makes no sense other then some inspectors wanted to see one so the manufacture put it there

There is a metal strap that runs from the internal ground lug to the front of the forming shell where the light assembly mounts.

 

[Dennis Alwon]

There is a metal strap that runs from the internal ground lug to the front of the forming shell where the light assembly mounts.

Well, if that's the case I suspect you better run the wire regardless of what the inspector says

 

[Little Bill]

I have never seen a plastic light housing or niche that had a bonding lug.

Plus, there is this:

(5) Luminaire Bonding. The luminaire shall be bonded to,
and secured to, the forming shell by a positive locking device
that ensures a low-resistance contact and requires a tool to
remove the luminaire from the forming shell. Bonding shall
not be required for luminaires that are listed for the application
and have no non–current-carrying metal parts.

 

[Dennis Alwon]

I have never seen a plastic light housing or niche that had a bonding lug.

Plus, there is this:

Except that there is a metal piece in the shell according to curt

 

[Mystic Pools]

All plastic niches have a bond lug on the inside and on the backside. The inside lug MUST be coated with a potting compound. That bond wire runs through the common conduit for the light cord and attaches to the bond lug on the deck box.

The lug on the backside of the niche is attached to pool's structure whether it be rebar on a concrete pool, or the steel panels on a vinyl pool.
Some inspectors want the attachment on the backside to pig-tailed/unbroken as part of the bond wire attached to the structure's frame (rebar or steel panel). Some are ok with a separate bond wire from the backside to the frame.
We always ran it as part of the common bond on the frame which would terminate at the motors and any other devices on the equipment pad.

Here's a pic on Amazon of a plastic niche. You can zoom in on photo to see bond connections on the inside and the backside

https://www.amazon.com/Hayward-SP06...ateway&sprefix=hayward+light+n,aps,144&sr=8-3

 

[Dennis Alwon]

So if everything is plastic why is there a need for a lug. Sounds like they introduced metal-- my guess is that it is for the screws that hold the light fixture in place

 

[readydave8]

So if everything is plastic why is there a need for a lug.

Not pool light, but I think I remember lug on plastic pump housing? And the reason was so bonding wire would be present if pump was ever changed to one with metal housing?

 

[guschash]

Thanks for all replies. On rereading Wet-Niche I see where Luminaire bonding says " Bonding shall not be required for luminaries that listed for the application and have no non-current metal parts. But doesn't counter what Atricle 680.23(B)(2) says about that the bonding conductor serves as a path for ground-fault current.

 

[Dennis Alwon]

Not pool light, but I think I remember lug on plastic pump housing? And the reason was so bonding wire would be present if pump was ever changed to one with metal housing?

Yeah but that pool shell is not going to be changed without major demolition of the pool

 

[Mystic Pools]

So if everything is plastic why is there a need for a lug. Sounds like they introduced metal-- my guess is that it is for the screws that hold the light fixture in place

You are exactly correct. It's to bond the light fixture itself with the mounting screw. The light fixture's body is stainless. Some have plastic trim face and some are chrome plated and stainless.

I'm pretty certain stainless steel niches are still available. There's a lot of them out there.

 

[shortcircuit2]

So if everything is plastic why is there a need for a lug. Sounds like they introduced metal-- my guess is that it is for the screws that hold the light fixture in place

The "Metal Strap" and "Metal Trim Ring" inside the wet niche also establish the required water bond I believe...

 

[Mystic Pools]

The "Metal Strap" and "Metal Trim Ring" inside the wet niche also establish the required water bond I believe...

That's a great detail. That's it exactly. Yes, the metal strap and the metal trim when joined with the screw, provide the bond. I guess I'm surprised the detail does not show potting compound to be applied to the lug inside the niche.

FYI: There is a product out there that has been around for sometime called the Light Wedge. Some niches tabs where the light fixture screws in, break off. Not really sure why-perhaps chemical damage. Anyway, this Light Wedge allows the light fixture to be secured inside the niche to prevent it from falling out by wedging itself in place. Problem is, it does not bond the light fixture. That's bad.

You can google it or see it on Amazon.

 

[Dennis Alwon]

I just assumed everything on the light was plastic. Plastic niche, plastic light and plastic screws or some other means to attach the light. We don't do the wiring inside the pool as the pool companies have licenses for that specifically so I don't get to see the lights in the pool.

Thanks for the education and a great detail drawing of the light fixture and niche