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:will...@millersolar.com>will...@millersolar.com>Date: Fri, October 21, 2011 10:51 amTo: RE-wrenches <<mailto:re-wrenches@lists.re-wrenches.org>re-wrenches@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:will...@millersolar.com>will...@millersolar.com http://millersolar.com License No. C-10-773985 ---------- _______________________________________________ List sponsored by Home Power magazineList Address: <mailto:RE-wrenches@lists.re-wrenches.org>RE-wrenches@lists.re-wrenches.orgOptions & settings: <http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org>http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.orgList-Archive: <http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org>http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.orgList rules & etiquette: <http://www.re-wrenches.org/etiquette.htm>www.re-wrenches.org/etiquette.htm Check out participant bios: <http://www.members.re-wrenches.org>www.members.re-wrenches.org_______________________________________________ List sponsored by Home Power magazineList Address: <mailto:RE-wrenches@lists.re-wrenches.org>RE-wrenches@lists.re-wrenches.orgOptions & settings: <http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org>http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.orgList-Archive: <http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org>http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.orgList rules & etiquette: <http://www.re-wrenches.org/etiquette.htm>www.re-wrenches.org/etiquette.htm Check out participant bios: <http://www.members.re-wrenches.org>www.members.re-wrenches.org_______________________________________________ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.orgList-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.orgList rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org No virus found in this incoming message. Checked by AVG - www.avg.comVersion: 8.5.454 / Virus Database: 271.1.1/3962 - Release Date: 10/19/11 14:06:00
Miller Solar Voice :805-438-5600 email: will...@millersolar.com http://millersolar.com License No. C-10-773985
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