International Association of Electrical Inspectors [RE-wrenches]

Fri Mar 7 10:41:09 PST 2008

William,

As NEC PV trainers begin to proliferate in this new age of PV, it is partly
my responsibility under the Dept of Energy--Code Officials panel to be aware
of these issues and try to address misconceptions as they arise. Please
forward this gentleman's contact information to me as I would be happy to
discuss the grounding issue with him. Unfortunately, there has been a lot of
doubt placed upon grounding clips that is misguided. UL is in the process of
having the module manufacturers more clearly define their grounding options,
but this makes me nervous. I have not heard any responses on this subject,
and it is in the manufacturer's interest not to undertake new testing, so
the status quo is a likely outcome. I applaud UL for taking the initiative
to deal with this issue, and hope that my fears are misplaced.

Grounding and bonding is generally well understood in the electrical world.
The biggest difference with PV systems is that all the bonds are outside.
Most electricians deal with indoor grounding methods. In an outdoor
location, we have to be more careful with corrosion and deterioration of
connections. The ILSCo direct burial lay-in lug has been recommended for
many years, is listed to UL467 (not UL1703), has worked well if properly
installed with a nut and bolt, but is very expensive and time consuming.
Grounding clips are specifically listed for PV modules and specific racks
and represent the most code-compliant method of grounding and bonding a PV
module. It will be great when manufacturer's literature is more
specific--however, there is a real danger with going more specific. That
danger is that it sets a bad precedent that every grounding method must be
specifically called out in the literature. Since the literature has
historically lacked detail of any kind, this does not speak well of
flexibility or ingenuity and doing the process better. In all likelihood we
will take three steps back after making two steps of progress.

I will continue to support the use of grounding clips until a clearly
superior and must better documented product becomes available--I'm not
holding my breath for such a product.

Bill.

Bill Brooks, PE
Brooks Engineering
873 Kells Circle
Vacaville, CA 95688
office and mobile: (707) 332-0761
fax: (707) 451-7739
email: bill at brooksolar.com
web: www.brooksolar.com

Ecclesiastes 11:7 Truly the light is sweet, And it is pleasant for the eyes
to behold the sun

-----Original Message-----
From: William Miller [mailto:wrmiller at charter.net] 
Sent: Thursday, March 06, 2008 11:17 PM
To: RE-wrenches at topica.com
Subject: International Association of Electrical Inspectors [RE-wrenches]

Colleagues:

As it so happens, the IAEI is holding a three day seminar here in our 
county seat.  The agenda included two half day sessions on PV installation 
code compliance and inspections.  I attended one of the sessions 
today.  The first presenter is a plan checker with the City of San Carlos 
California.

The first issue discussed was generated by a question from an installer and 
was on the subject of fusing parallel strings.  I was under the impression 
that John Berdner's position as expressed in his white paper on fusing of 
strings was pretty well accepted in the industry.  This has been discussed 
thoroughly here in this forum.  The only caveat to Berdner's logic is there 
must be some proof that the inverter can not contribute to PV fault 
current, even in a failure of the inverter.  Proof can come in the form of 
results of independent testing and a statement from the manufacturer.

The presenter does not accept this logic.  His opinion is that, if the PV 
manufacturer lists a maximum fuse size in any literature, an installer must 
install a fuse.  The mere mention of a fuse in product literature means 
that, unless specifically stated otherwise, the manufacturer requires one 
and manufacturer's requirements can not be waived by any language in the
NEC.

Furthermore, the presenter is not allowing use of the Wiley Electronics 
WEEB clips in his jurisdiction because the ETL listing for these clips is 
under UL467 which applies generically to the grounding of non-current 
carrying metallic parts.  His problem is that unless the listing is under 
UL1703, PV systems, the 467 listing does not allow for their use in PV
systems.

I sent an e-mail then and there to Wiley asking for clarification.  Problem 
is, I just ordered and received about $1,000 worth of WEEB clips and all of 
the local inspectors where in the room hearing how they should not allow me 
to use these as accepted grounding.  After the session I noticed that Wiley 
addresses the 1703 versus 467 on their website at this 
address:  http://www.we-llc.com/WEEB.html  See the Summary for inspectors 
section.

Do any of you on this list do business in San Carlos, and if so, how ever 
do you get anything past plan check?  Furthermore, I assume most of you are 
avoiding the use of fuses in string quantities of two or less, so this 
school of thought is going to cost you (and your customers) some cash.  How 
do you all feel about this?  Lastly, is anyone here using WEEB clips and 
have you had their legality questioned?

Thanks for your input.  I apologize for being such a curious so and so.

William Miller

-- _________________________________
William Miller
Miller Power and Communications
Voice :805-438-5600     Fax: 805-438-4607
email: wrmiller at mpandc.com
http://mpandc.com
License No. C-10-773985

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