[RE-wrenches] Guarding against live parts 690.7 (D)
William Miller
william at millersolar.com
Thu Sep 10 16:32:36 PDT 2015
Ray:
I apologize but I thought this discussion was off-line.
Mike Holy and everyone but apparently our local AHJ agree: wire guarding is required.
William
> On Sep 10, 2015, at 4:04 PM, Ray Walters <ray at solarray.com> wrote:
>
> I'm confused again. Do we need to guard ground mount arrays or not? I thought it was clear that we did need to guard the array wiring.
>
> R.Ray Walters
> CTO, Solarray, Inc
> Nabcep Certified PV Installer,
> Licensed Master Electrician
> Solar Design Engineer
> 303 505-8760
>> On 9/9/2015 6:46 PM, William Miller wrote:
>> Bill:
>>
>> How right you are. I spoke with Mike Stoker of the County of San Luis Obispo today and he told me that both you and Mike Holt are saying that guards are not required on readily accessible wiring. I sent him your recent email to me on the subject. He may be in touch. If you want to write him, his email is mstoker at co.slo.ca.us.
>>
>> I looked on Mike Holt’s site and did not see anything from Mike about wire guarding. I wrote to Mike and asked him directly. I will let you know what I learn.
>>
>> William
>>
>>
>> <mime-attachment.jpg>
>> Lic 773985
>> millersolar.com
>> 805-438-5600
>>
>> From: RE-wrenches [mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of billbrooks7 at sbcglobal.net
>> Sent: Saturday, September 05, 2015 2:21 PM
>> To: 'RE-wrenches'
>> Subject: Re: [RE-wrenches] Guarding against live parts 690.7 (D)
>>
>> William,
>>
>> You can always quote me to an AHJ, as long as I actually said it or wrote it.
>>
>> I have been accused of saying all kinds of things that I never said—people just misunderstood what I said and “quoted” me incorrectly.
>>
>> All the best—and stay safe. Always tragic to hear of electrocutions—most are so preventable as this one clearly was. Never, ever assume that a circuit is off. I know you warned against inductive sensors, but they should still be used as one of several methods to detect voltage. I just watched a video about a guy who thought he was testing a 480V circuit when it was really a 12kV circuit. The fireball caught him on fire and burned him to death. The meter was the problem. An inductive sensor would have saved his life. There is no single method for safety.
>>
>> Bill.
>>
>> From: RE-wrenches [mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of William Miller
>> Sent: Friday, September 04, 2015 2:37 PM
>> To: RE-wrenches <re-wrenches at lists.re-wrenches.org>
>> Subject: Re: [RE-wrenches] Guarding against live parts 690.7 (D)
>>
>> Bill:
>>
>> I apologize that I assumed incorrectly. Thank you for your assessment. May I quote you to our AHJ?
>>
>> Sincerely,
>>
>> William
>>
>>
>>
>> Lic 773985
>> millersolar.com
>> 805-438-5600
>>
>> From: RE-wrenches [mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of billbrooks7 at sbcglobal.net
>> Sent: Friday, September 04, 2015 12:59 PM
>> To: 'RE-wrenches'
>> Subject: Re: [RE-wrenches] Guarding against live parts 690.7 (D)
>>
>> William,
>>
>> I’m shocked and offended (a tiny bit) that you would prejudice yourself to not agree with me ;-).
>>
>> First of all I have been heavily involved in the revising of the language in 690.31(A) to make it clear that we cannot walk up and touch cables operating at 600V. The term guarded is a defined term:
>>
>> Guarded. Covered, shielded, fenced, enclosed, or otherwise
>> protected by means of suitable covers, casings, barriers,
>> rails, screens, mats, or platforms to remove the likelihood
>> of approach or contact by persons or objects to a point
>> of danger.
>>
>> A fence actually does not prevent ready access (unless it does not have a gate), but the term guarded fixes that problem. The guarding means has to be approved by the AHJ, but many methods have been employed including mounting lattice work around the backside of fixed ground-mounted systems.
>>
>> Fences are best used for larger systems (over 50-100kW) whereas other methods—albeit labor intensive—are generally preferred for smaller installations (under 100 kW)
>>
>> No intelligent person would disagree with this proper interpretation of the NEC—including you.
>>
>> Bill.
>>
>>
>> From: RE-wrenches [mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of William Miller
>> Sent: Friday, September 04, 2015 12:09 PM
>> To: RE-wrenches <re-wrenches at lists.re-wrenches.org>
>> Subject: Re: [RE-wrenches] Guarding against live parts 690.7 (D)
>>
>> Ray:
>>
>> 1. Why no fence? Aesthetics. Also costs may be a wash by the time you mobilize a fencing contractor.
>> 2. I’d apply the same requirements to a fence as one would to an uncovered swimming pool. There are the same consequences if a child ends up in the wrong place.
>> 3. Why bother?
>> We figure the expense will decrease as we figure better design and implementation. Hasn’t yet.
>> We care about safety. I figure we, as an industry, will kill a child by electrocution someday—it is a matter of probability. I hope it won’t be on one of our jobs.
>> We hope, in some small way, we influence the industry to improve.
>> 4. The industry has not developed solutions because there is no demand. There is no demand because AHJs don’t enforce the code.
>>
>> Thanks for the compliment. We have several new designs not yet featured on the web site. Check back next time this comes up.
>>
>> William
>>
>> PS: I am curious what Bill Brooks take on this is, but I don’t think I will agree with his interpretation.
>>
>> W
>>
>>
>>
>> Lic 773985
>> millersolar.com
>> 805-438-5600
>>
>> From: RE-wrenches [mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Ray Walters
>> Sent: Friday, September 04, 2015 11:37 AM
>> To: RE-wrenches
>> Subject: Re: [RE-wrenches] Guarding against live parts 690.7 (D)
>>
>> WilIiam;
>>
>> checked out your guards on your website, that looks really clean, but also like a lot of work and expense. I'm still so surprised manufacturers are not offering an option like that to their frame systems.
>> My question: how come you didn't just fence the array? Shading issues on the south?
>> If fencing, what height of fence is considered adequate? 4 ft? 6 ft?
>>
>> R.Ray Walters
>> CTO, Solarray, Inc
>> Nabcep Certified PV Installer,
>> Licensed Master Electrician
>> Solar Design Engineer
>> 303 505-8760
>> On 9/4/2015 9:44 AM, William Miller wrote:
>> Gary:
>>
>> I think the issue of PV wiring behind module that are readily accessible is addressed in (2014) 690.31:
>>
>> Where PV source and output circuits operating at maximum
>> system voltages greater than 30 volts are installed in
>> readily accessible locations, circuit conductors shall be
>> guarded or installed in a raceway.
>>
>> I am not sure what application the original poster had in mind, but this is the question I think you are asking. The interpretation to 690.31 seems clear to me: No one should be able to touch the conductors without resorting to a ladder, opening a locked gate or removing a protective panel. Readily accessible is defined thusly:
>>
>> Capable of being
>> reached quickly for operation, renewal, or inspections
>> without requiring those to whom ready access is requisite
>> to actions such as to use tools, to climb over or remove
>> obstacles, or to resort to portable ladders, and so forth.
>>
>> Implementing this is harder than it might seem. Lacking a fence, the installer must either use the flimsy solar-scrim product or fabricate his or her own shielding. We have put a fair amount of effort towards this. See link.
>>
>>
>> William
>>
>>
>>
>>
>>
>> Lic 773985
>> millersolar.com
>> 805-438-5600
>>
>> From: RE-wrenches [mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of gary easton
>> Sent: Friday, September 04, 2015 2:22 AM
>> To: RE-wrenches
>> Subject: Re: [RE-wrenches] Guarding against live parts 690.7 (D)
>>
>> Bill
>> Are you saying there is no requirement to shield wires on a ground array?
>>
>> On Friday, September 4, 2015, <billbrooks7 at sbcglobal.net> wrote:
>> Craig,
>>
>> This one is easy to misinterpret. You missed the words “live parts”. This has been removed from the 2017 NEC because it is actually referring to load circuits being fed directly by a PV system on the dc side. All references to loads and batteries are being removed from 690.
>>
>> This is a complete non-issue.
>>
>> Bill.
>>
>> From: RE-wrenches [mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Craig Gerald Buttke
>> Sent: Thursday, September 03, 2015 11:44 AM
>> To: re-wrenches at lists.re-wrenches.org
>> Subject: [RE-wrenches] Guarding against live parts 690.7 (D)
>>
>>
>>
>> How is everyone handling 690.7 (D)
>>
>> Circuits over 150 Volts to Ground. In one- and two- family dwellings, live parts in photovoltaic source circuits and photovoltaic output circuits over 150 volts to ground shall not be accessible to other than qualified persons while energized.
>>
>>
>> If you have a commercial (non one or two-family dwelling) are you screening your ground mount arrays to keep people from touching live conductors PV wires)?
>>
>> Thanks for your thoughts
>>
>> --
>> Yours in Solardarity,
>>
>> Craig Gerald Buttke
>>
>> M:(715) 630-1227
>> O:(715) 630-6451
>> F:(715) 952-4501
>>
>> North Wind Renewable Energy, LLC
>> 1626C W Pearl Street
>> Stevens Point, WI 54481
>>
>> www.northwindre.com
>>
>> NABCEP Certified PV Installation Professional™
>> NABCEP Certified PV Technical Sales Professional™
>> State of WI: Master Electrician
>>
>>
>>
>> This email has been checked for viruses by Avast antivirus software.
>> www.avast.com
>>
>>
>>
>>
>> --
>> Sent from Gmail Mobile
>>
>>
>> _______________________________________________
>> List sponsored by Redwood Alliance
>>
>> List Address: RE-wrenches at lists.re-wrenches.org
>>
>> Change listserver email address & settings:
>> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>>
>> List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html
>>
>> List rules & etiquette:
>> www.re-wrenches.org/etiquette.htm
>>
>> Check out or update participant bios:
>> www.members.re-wrenches.org
>>
>>
>>
>>
>>
>> This email has been checked for viruses by Avast antivirus software.
>> www.avast.com
>>
>>
>>
>>
>>
>> This email has been checked for viruses by Avast antivirus software.
>> www.avast.com
>>
>>
>>
>>
>> _______________________________________________
>> List sponsored by Redwood Alliance
>>
>> List Address: RE-wrenches at lists.re-wrenches.org
>>
>> Change listserver email address & settings:
>> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>>
>> List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html
>>
>> List rules & etiquette:
>> www.re-wrenches.org/etiquette.htm
>>
>> Check out or update participant bios:
>> www.members.re-wrenches.org
>>
>
> _______________________________________________
> List sponsored by Redwood Alliance
>
> List Address: RE-wrenches at lists.re-wrenches.org
>
> Change listserver email address & settings:
> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>
> List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html
>
> List rules & etiquette:
> www.re-wrenches.org/etiquette.htm
>
> Check out or update participant bios:
> www.members.re-wrenches.org
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org/attachments/20150910/f9369b00/attachment-0002.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: mime-attachment.jpg
Type: image/jpeg
Size: 1460 bytes
Desc: not available
URL: <http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org/attachments/20150910/f9369b00/attachment-0012.jpg>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: mime-attachment.jpg
Type: image/jpeg
Size: 1460 bytes
Desc: not available
URL: <http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org/attachments/20150910/f9369b00/attachment-0013.jpg>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: mime-attachment.jpg
Type: image/jpeg
Size: 1460 bytes
Desc: not available
URL: <http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org/attachments/20150910/f9369b00/attachment-0014.jpg>
More information about the RE-wrenches
mailing list