2 pool questions

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bphgravity

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1. 680.23(B)(2)(b) requires an INSULATED #8 conductor to be run in the conduit between the forming shell of a wet niche pool light to the junction box.

Question: What is the reasoning for the #8 to be installed within the conduit and why must it be insulated?

2. 680.24(B) permits a pool light transformer enclosure to connect directly to the conduit extending to the forming shell without a listed pool light j-box. Many, including the common Intermatic transformer, are marked as suitable for direct connection to the pool light.

Question: How do the typical transformer enclosures comply with 680.24(B)(1)(1)? A standard RNC terminal adaptor and locknut isn't considered a "hub" is it?
 
bphgravity said:
No comments? Not even one?
Click to expand...

Let me be the first to comment...
No comment.
Just kidding. I don't work on many swimming pools, so this is just my swag on the reasoning.
The grounding conductor is insulated for two reasons.
(1) To minimize corrosion caused by pool chemicals.
(2) To return the fault current directly to the source without it paralleling through any conductive path that it may touch, including pool water and the people in it. The reason for the #8cu plays a part in this too. Since current flows thru all paths, but the bulk of the current flows thru the path of least resistance, the lower the resistance of the grounding circuit the more fault current will take this path. This leaves less current to flow on parallel paths.
Like I said, just A SWAG.
steve
 
My guess, as far as question 1, is that
1) #8 was chosen for these swimming pool equipotential systems, as mentioned in the commentary following 680.6-Grounding.*
2) When replacing lamp, an RNC conduit is not bonded into the equipotential grid. In case there's a damaged wire, the insulation makes that conductor 'touchproof.' Which means, in the only sense I can make of this rule, that the housing will not contain voltage from a broken wire in the conduit. A metallic conduit would, by definition, be at the local voltage.

* 680 jumps from grounding, to bonding, to this, to that. 680.23(B)(1) states the #8 bonding requirement, then 680.23(B)(5) is titled, "Luminaire (Fixture) Bonding." The #8 bonding conductor is again mentioned in the commentary following 680.24(F), now being called a 'secondary equipment grounding conductor.' I needed more information, in the form of a picture, to make sense of that section. Hopefully I'm just not understanding something.
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Your second question shows, correctly, more problems with the text (in my opinion.) The intermatic site shows their boxes clearly to be simple stamped steel, with knockouts. How that fits in with 'threaded entries...' is beyond me. In addition, it is quite confusing to discuss a specific listed item (the direct connect transformer enclosure or the junction box) and suddenly reference something from chapter 3, my expectation is that the related UL equipment is a unique swimming pool item which is listed for swimming pool applications. Intermatic does not even mention fittings. Certainly hazardous locations are treated more completely than this is.
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Bryan, I'm glade somebody besides me has asked this question cause when I asked it , I got no answers. First, the # 8 from the shell to the j-box servers no purpose. It does nothing!!!! EXCEPT TO PROVIDE AN ALTERITIVE MEANS OF CONNECTION TO THE REBAR WHEN THE PRIMARY LEAD HAS BEEN CUT. You would be suprised ar how many times I have found no connection from the cage to the steel. When I suggest they use the #8 at the j-box they look at me like I have 2 heads. That #8 is hooked to the inside and the out side of the wet nitch and to the pool steel.

As for why it must be insulated, I do not know.


I have not seen direct light to transformer connections. J-box is used but we do allow pvc boxes with slip glue connectors.

I have many time in the past, Pvc LB'd out of the transformer straight to the light. I see no problem with this.

Remeber a few weeks ago when I said " Didn't I just hook the #8 pool steel bond to the panel useing the #12 pool motor grounddinig conductor? Nobody answered that question.
 
Thanks for all the responses guys.

Someone else has told me they believe the intermatic transformers are both CSA and UL listed. The CSA listing permits the direct connection whereas the UL listing does not. The problem is that John Minick from NEMA indicated in a recent letter to a neighboring jurisdiction that direct connection to a transformer enclosure marked with this allowance should be approved.

I've always been curious about the insulated #8 issue and had assumed it was for corrosion protection, hence the potting compond, ect...

Thanks again!
 
Bryan,

Q1. Is for non-metalic raceway between the wet niche forming shell and the

enclosure [ie. j-box]. Without that #8 there is no continuity between the

metal of the forming shell and the enclosure. The lamp is gasketed into the

forming shell,thus leaving the egc in the molded cord isolated from the shell.

Q2. Non-metalic hub ???? still looking!
 
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