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 [email protected]
<mailto:[email protected]>.
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
Gradient Cap_mini
Lic 773985
millersolar.com <http://www.millersolar.com/>
805-438-5600
*From:*RE-wrenches [mailto:[email protected]
<mailto:[email protected]>] *On Behalf Of
*[email protected] <mailto:[email protected]>
*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:[email protected]]
*On Behalf Of *William Miller
*Sent:* Friday, September 04, 2015 2:37 PM
*To:* RE-wrenches <[email protected]
<mailto:[email protected]>>
*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
Gradient Cap_mini
Lic 773985
millersolar.com <http://www.millersolar.com/>
805-438-5600
*From:*RE-wrenches [mailto:[email protected]
<mailto:[email protected]>] *On Behalf Of
*[email protected] <mailto:[email protected]>
*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:[email protected]]
*On Behalf Of *William Miller
*Sent:* Friday, September 04, 2015 12:09 PM
*To:* RE-wrenches <[email protected]
<mailto:[email protected]>>
*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
Gradient Cap_mini
Lic 773985
millersolar.com <http://www.millersolar.com/>
805-438-5600
*From:*RE-wrenches [mailto:[email protected]
<mailto:[email protected]>] *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
<http://www.millersolar.com/MillerSolar/practices/PV_wiring/Wire_shielding/_Wire%20Shielding_history.html>.
William
Gradient Cap_mini
Lic 773985
millersolar.com <http://www.millersolar.com/>
805-438-5600
*From:*RE-wrenches
[mailto:[email protected]
<mailto:[email protected]>] *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, <[email protected]
<mailto:[email protected]>> 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:[email protected]
<javascript:_e(%7B%7D,'cvml','[email protected]');>]
*On Behalf Of *Craig Gerald Buttke
*Sent:* Thursday, September 03, 2015 11:44 AM
*To:* [email protected]
<javascript:_e(%7B%7D,'cvml','[email protected]');>
*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 <http://www.northwindre.com>
NABCEP Certified PV Installation Professional™
NABCEP Certified PV Technical Sales Professional™
State of WI: Master Electrician
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