Wet-niche luminaire grounding

[ctroyp]

I have been questioned by a friend on grounding an under water luminaire. He asked me to find the article for sizing the egc for the under water lum. He states that he ran an 8 awg to the lug on the mounting enclosure. He did not run another ground to the cord connected lamp housing inside that mounting enclosure because it already has an egc inside the cable. There is a lug outside of the lamp housing that he did not run an egc to.

The inspector wants him to run an insulated 8 awg to that lamp enclosure. There is already an 8 awg to the housing in the pool wall and a 12 awg to the lamp enclosure.

Under 680.23 (B)(3) and (F)(2) I told him that a insulated 12 awg should be sufficient (per code)since the current carrying conductors are 12 awg. Aside from the AHJ having the upper hand, there is no room in the conduit to run an insulated 8 awg.

Am I giving the correct information or am I missing something?

 

[Guest]

Re: Wet-niche luminaire grounding

Is the niche conduit metal or plastic?

If plastic, also look at 680.23(B)(2).

For bonding of the fixture to the niche look at 680.23(B)(5).

[ September 24, 2003, 12:01 PM: Message edited by: awwt ]

 

[ctroyp]

Re: Wet-niche luminaire grounding

Non-metallic...
The "forming shell" mounted to the pool wall that houses the cord connected lampholder has an 8awg bonding it but not the lampholder. The lampholder is cord connected w/12 awg ground but there is a terminal on the lampholder that is where the inspector wants the 8 awg ground???

The lampholder doesn't fall under 680.23(B)(2) in my interpretation.

 

[earlydean]

Re: Wet-niche luminaire grounding

Pool wet-nitch luminaires require redundant grounding. Outside the housing must be bonded, inside must be bonded, the housing will bond through a positive locking device to the lamp enclosure, and the lamp itself will also have a EGC in the cord.
680.23(B)(1),(2),(3)and (5); 680.26(B)(2) and (C)
Earl

 

[ctroyp]

Re: Wet-niche luminaire grounding

earlydean:
The question is...does the redundant ground going to the lampholder(housing) have to be a 8 awg or 12 awg? There is already a 12 awg going to the lamp within the cable but nothing on the lug of the lamp housing. There is also an 8 awg going to the forming shell.

[ September 24, 2003, 02:45 PM: Message edited by: ctroyp ]

 

[ctroyp]

Re: Wet-niche luminaire grounding

Here is a quickly drawn sketch of what I am refering to.

Sorry, my mistake, metallic forming shell.

[ September 24, 2003, 03:19 PM: Message edited by: ctroyp ]

 

[websparky]

Re: Wet-niche luminaire grounding

2002 NEC 680.26 Bonding
(B)(2) Underwater Lighting. All forming shells and mounting brackets of no-niche luminaires (fixtures) shall be bonded unless a listed low-voltage lighting system with nonmetallic forming shells not requiring bonding is used.

680.23 (B)(5) Luminaire (Fixture) Bonding.
The luminaire (fixture) 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 (fixture) from the forming shell. Bonding shall not be required for luminaires (fixtures) that are listed for the application and have no non?current-carrying metal parts.

The inspector may be referring to the bonding requirements which is totally separate from grounding requirements.

[ September 24, 2003, 06:47 PM: Message edited by: websparky ]

 

[ctroyp]

Re: Wet-niche luminaire grounding

So what size 12 awg or 8 awg?

PS: Sorry about the sketch not showing above, Yahoo wants to charge me to store public files now--I'll figure something out...

[ September 24, 2003, 09:05 PM: Message edited by: ctroyp ]

 

[Ed MacLaren]

Re: Wet-niche luminaire grounding

I am not in the USA, so I don't know the NEC rules on this very well, but it has always been my belief that #8 (#6 in Canada) conductors are only required to be used for the exposed conductors used to bond non-current-carrying metal parts together for voltage gradient reduction, around pool and similar installations.

There are two kinds of "bonding conductors".

1. Circuit "fault-clearing" bonding (EGCs) conductor sizes are normally determined by the circuit OCPD and are required to be run in the conduit or cable with the other conductors of that circuit, and are protected from damage.

2. The bonding conductors used to eliminate voltage gradients between non-current-carrying metal parts are not normally installed in conduit or cable, and are exposed to damage. These are the ones that are required to be # 8.
See example sketch below.

The same reasoning applies to any equipment bonding for voltage gradient reduction, in installations such as livestock barns, etc.

Ed

[ September 24, 2003, 09:42 PM: Message edited by: Ed MacLaren ]

 

[rickg]

Re: Wet-niche luminaire grounding

earlydean is correct, your friend must run an insulated #8 copper conductor between the listed for use junction box & the wet niche pool light/s, if he is using PVC conduit between the light & the j box. It is a redundant ground, & the termination in the wet niche housing must be encapsulated with a listed potting compound. I think that 3M is the only company that makes this compound. If the conduit between the light & j box is brass/ bronze the #8 ground is not necessary.
RickG

 

[ctroyp]

Re: Wet-niche luminaire grounding

Sorry for the delay of the sketch. Thanks to Wayne for posting it for me.

I agree with what everyone is stating about the 8 awg bonding wire to the forming shell, but it's the lamp holder in question.

 

[websparky]

Re: Wet-niche luminaire grounding

Looks like an EGC to me!

#12AWG.

 

[ctroyp]

Re: Wet-niche luminaire grounding

Does anyone else agree or disagree on the 12 awg.

From my interpretation of the code, I believe it should be a 12 also.

 

[ctroyp]

Re: Wet-niche luminaire grounding

Just to put in an update on how his project turned out--the inspector allowed him to run an 8 awg stranded so he could get it in the pvc pipe.

He still should have been able to run a 12 awg.

Anyhow just wanted to update those who viewed and participated in this topic. Thank you.

I guess we'll sleep on it for now...