[RE-wrenches] cable spacing in trenches

[Drake]

Check out Figure Figure B.310.15(B)(2)(1)



At 07:43 AM 11/4/2011, you wrote:
>Separation is an issue the NEC does not address clearly .However, 
>please make sure you allow adequate room to repair the conduit if 
>damaged, and 12' seems to be the magic number. I lso had no luck 
>looking in 490.
>
>NEC 300.4(C)(2)(e) also seems a bit relevant where it allows for 
>conductors of different voltage ratings in manholes "if the 
>conductors of each system are permanently and effectively separated 
>from the conductors of the other systems...", but again this may be 
>referring to separate trenches with different system voltage ratings 
>entering the same manhole for tapping, allowing access for 
>maintenance or other uses.
>
>
>
>On Thu, Nov 3, 2011 at 5:42 PM, Jerry Caldwell 
><<mailto:solarcowboy at yahoo.com>solarcowboy at yahoo.com> wrote:
>Can anyone direct me to the NEC article that stipulates how many 
>inches of separation must be between cables operating at different voltages?
>
>I have a project with PV combiner box home runs at 1,000 volts DC in 
>the same trench with 12.47 kV cables.  Table 300.5 shows minimum 
>cover requirements for direct burial cables, but this is the 
>distance beneath grade the cables must be.  Is there anywhere in the 
>code that calls for a minimum separation distance between cables at 
>different voltages?
>
>Thanks,
>Jerry Caldwell
>
>
>
>
>From: Marco Mangelsdorf <<mailto:marco at pvthawaii.com>marco at pvthawaii.com>
>To: 'RE-wrenches' 
><<mailto:re-wrenches at lists.re-wrenches.org>re-wrenches at lists.re-wrenches.org>
>Sent: Thursday, November 3, 2011 2:27 PM
>Subject: [RE-wrenches] under performing Enphase inverters
>
>For the first time, several weeks ago, after 40-50 Enphase installs, 
>we've come across at least two M210s that we putting out 
>consistently lower outputs than their immediate neighbors.
>
>We replaced the two mods first, which made no difference.  Then, in 
>consultation with Enphase, replaced the M210s.  After replacing 
>them, the power output was as it should be.
>
>Now I've got another suspect system with several underperforming 
>mods out of (36).
>
>Has anyone else had this experience?
>
>Thanks,
>marco
>
>
>_______________________________________________
>List sponsored by Home Power magazine
>
>List Address: 
><mailto:RE-wrenches at lists.re-wrenches.org>RE-wrenches at lists.re-wrenches.org
>
>Options & settings:
><http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org>http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>
>List-Archive: 
><http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org>http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>
>List 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: 
><mailto:RE-wrenches at lists.re-wrenches.org>RE-wrenches at lists.re-wrenches.org
>
>Options & settings:
><http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org>http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>
>List-Archive: 
><http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org>http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>
>List 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
>
>
>
>
>
>--
>James B Rudolph
>NABCEP Certified PV Installer
>
>
>_______________________________________________
>List sponsored by Home Power magazine
>
>List Address: RE-wrenches at lists.re-wrenches.org
>
>Options & settings:
>http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>
>List-Archive: 
>http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>
>List rules & etiquette:
>www.re-wrenches.org/etiquette.htm
>
>Check out participant bios:
>www.members.re-wrenches.org

Drake Chamberlin
ATHENS ELECTRIC LLC
OH License 44810
CO license 3773
NABCEP Certified PV
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org/attachments/20111106/d7f3cc26/attachment-0003.html>