[RE-wrenches] MC Cable for DC runs

[Jason Szrom]

Howie,

I've looked at a few different MC cable manufacturer data sheets and I can't find a distinction between AC or DC. In general I wouldn't expect there to be a difference since AC RMS voltage and current ratings are sort of a 'DC equivalent'. But the only way to be sure is contact a cable manufacturer and ask a specialist. There could be something buried in the listing. And we all know it is expensive to get a hold of UL standards to look the damn thing up ourselves.

Example MC cable data sheet:  http://www.afcweb.com/pdf_2011/p12_mc_s_lt.pdf

I am guessing that John Wiles was referring to 690.31(E) which has to do with running inside a building with DC conductors before hitting a DC disconnect. This section was changed in 2011 NEC to include MC cables specifically. Maybe from this it got lost in translation back to you?

Good luck,

Jason M. Szrom, PE
Engineering Supervisor
Solar Energy Systems, LLC
718-389-1545 x13

-----Original Message-----
From: re-wrenches-bounces at lists.re-wrenches.org [mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Howie Michaelson
Sent: Monday, October 21, 2013 2:15 PM
To: RE-wrenches
Subject: [RE-wrenches] MC Cable for DC runs

Hi All,

Just had a conversation with an electrician friend who took a John Wiles course for inspectors a couple of weeks ago, and he thought (but wasn't
sure) that John said in order for it to be code to use MC cable for PV homeruns inside the building envelope, the cable needed to be rated for DC.  This was new information to me, particularly since I've never heard of MC cable being rated specifically for DC.  Is this accurate information, and does anyone know what the wire spec would be for this?

Thanks,
Howie
--
Howie Michaelson
NABCEP Certified Solar PV Installer(tm)

Catamount Solar, LLC
Renewable Energy Systems Sales and Service VT Solar Electric & Hot Water Incentive Partner http://www.CatamountSolar.com
802-272-0004





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