[RE-wrenches] Integrating with Lightning Protection

[Garrison Riegel]

Thanks for the reference Brian and the link Jarmo.  Thanks also Glenn for the NEC reference, which is consistent with Dehn saying that PV systems on roofs should be bonded to lightning protection systems if the required “separation distance” cannot be maintained.  If this separation distance is not maintained then “flashover” could jump from the LPS to the array possibly resulting in fire.  This separation distance is based on a number of site specific factors and is not necessarily easy to determine unfortunately.  It looks like the distance will be just over 3’ for the project I’m working on…assuming I did my calculations correctly.        

 

Interestingly Dehn says that on buildings with metal roofs there is no way to maintain the necessary separation distance and therefore the PV array needs to be directly connected to the external LPS in all cases.

 

Ray, I like your approach, which sounds like the safest design especially when this “separation distance” can be maintained. 

 

Thanks all for the replies.  Much appreciated.

 

Garrison       

 

From: RE-wrenches [mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Glenn Burt
Sent: Thursday, June 04, 2015 3:46 PM
To: RE-wrenches
Subject: Re: [RE-wrenches] Integrating with Lightning Protection

 

Have you looked at NFPA 780-2011, standard for the installation of lightning protection systems as mentioned in 250.106?

I recently read somewhere else that any conductive material in contact with or in the vicinity of a LPS has a negative effect on the designed efficiency of the LPS, but have not investigated further.

Sincerely,
Glenn Burt
Sent from my 'smart' phone so please excuse grammar and typos.

  _____  

From:  <mailto:garrison at solarserviceinc.com> Garrison Riegel
Sent: ‎6/‎4/‎2015 14:03
To:  <mailto:re-wrenches at lists.re-wrenches.org> 'RE-wrenches'
Subject: [RE-wrenches]  Integrating with Lightning Protection

Wrenches,

 

Does anyone have any best practice recommendations (or books, articles, etc) for integrating a roof mounted PV system with a lightning protection system?  Bare #6 copper and a split bolt to the braided copper connecting air terminals?  At both ends of the array?

 

Or should we not bond these systems on the roof?  Opinions on a 2009 Wrenches thread varied, but I’ve heard it from a few sources that these should be bonded directly.  Wondering if there is a general consensus at this point?  Or strong opinions one way or the other?

 

Thanks for your thoughts.

 

Garrison Riegel

PV Operations Manager |  <http://www.solarserviceinc.com/> Solar Service Inc

[p] 847-677-0950 |  <mailto:garrison at solarserviceinc.com> garrison at solarserviceinc.com

 

NABCEP Certified PV Installation Professional™

 

 

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