[RE-wrenches] Wet locations: (was Push-in Wire Connectors)

[William Miller]

Ray/Jamie:

I think that a 3R installation may be superior to a Nema 4.  With a 3R any 
condensation build up can drain.

Thanks to all of you for another round of thoughtful, well informed, 
technical discussion.  This forum is very helpful and I really feel a lot 
of camaraderie even though we are interfacing on a text basis.

William Miller



At 04:08 PM 10/21/2011, you wrote:
>I started using the wet rated wire nuts, because I've found some corrosion 
>in old connectors in outdoor boxes. BTW, why don't you like the goo filled 
>wire nuts? They seem a decent and cost effective solution.
>  I agree with your idea that condensation and moisture buildup can occur 
> even in a NEMA 4 box, and the issue that I have is that breakers and fuse 
> holders in combiner boxes are definitely not wet rated. I wonder what 
> happens to the internal workings of a breaker after decades in an outdoor 
> box, but considering there are an awful lot of them around (at least AC) 
> I guess I'll get  another night's sleep in our less than perfect world of 
> PV wiring.
>
>Ray
>
>On 10/21/2011 9:05 AM, Jamie Johnson wrote:
>>William, the only explanation that I have found for using THWN-2 in 
>>conduit run through the attic is that during the day as the temperature 
>>in the attic increases, the air in the conduit expands, at night the 
>>opposite effect happens, the temperature in the attic decreases and the 
>>volume of air in the conduit contracts with the potential to bring in 
>>what ever climate conditions exist outside the conduit (In FL this could 
>>be humid air).
>>
>>Over time if there is humid air present, this could form condensation in 
>>the conduit or NEMA 4 rated enclosure, hence the need for wire and 
>>connections rated for a wet location.
>>
>>I have seen photos at inspectors meetings of NEMA 4 enclosures and 
>>conduit that contained water although I am not sure how often this would 
>>normally happen.
>>
>>Jamie Johnson
>>NABCEP Certified PV Technical Sales Professional
>>NABCEP Certified Solar PV Installer
>>
>>General Manager
>>SOLAR POWER ELECTRIC
>>988e514.jpg
>>
>>
>>
>>>-------- Original Message --------
>>>Subject: [RE-wrenches] Wet locations: (was Push-in Wire Connectors)
>>>From: William Miller 
>>><<mailto:william at millersolar.com>william at millersolar.com>
>>>Date: Fri, October 21, 2011 10:51 am
>>>To: RE-wrenches 
>>><<mailto:re-wrenches at lists.re-wrenches.org>re-wrenches at lists.re-wrenches.org>
>>>
>>>Friends:
>>>
>>>I have had plan checkers insist I use wet rated wire on rooftops even 
>>>though the wire was in either liquid tight or EMT with raintight 
>>>connectors.  I did not need to dispute this because we had specified 
>>>THHN wire that is also rated THWN for wet locations.  This discussion 
>>>makes me think I should have contradicted the requirement because I am 
>>>not sure wet rated wire is required inside dry conduit.  I will be 
>>>looking this up.
>>>
>>>I feel that you should not let an AHJ impose a requirement that is not 
>>>in the code because then you become bound to the new stricture.  I 
>>>realize that an AHJ can impose stricter requirements, but I insist that 
>>>it be in writing, required in advance of the job in question and that it 
>>>be required universally.  Otherwise, it's anarchy.
>>>
>>>William Miller
>>>
>>>
>>>Miller Solar
>>>Voice :805-438-5600
>>>email: <mailto:william at millersolar.com>william at millersolar.com
>>>http://millersolar.com
>>>License No. C-10-773985
>>>
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Miller Solar
Voice :805-438-5600
email: william at millersolar.com
http://millersolar.com
License No. C-10-773985
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