2008 NEC changes (was connectors) [RE-wrenches]

[John Berdner]

Sky/Wrenches:
 
Utility drops are normally not in readily accessible areas as defined
by NEC.
Also, utility drops are typically supported on a messenger cable which
provides support and strain relief to the cables.
If the array were next to a roof mounted utility drop then the new
requirement would not apply.
This is why we pushed for including the "readily accessible" phrase in
the requirement.
Originally it was just accessible and that would have been much worse.
 
I agree that we have to balance safety and cost.
The NEC is not the worst in this respect.  IEEE 1547 was driven largely
by the utilities and the new requirements have doubled the time and cost
for UL Listing of inverters.
In the past we (the solar industry) tried to do everything to eliminate
all risks.
In the Standards community I am advocating moving to quantify the risks
before we add new requirements that add cost. 
In the area of islanding for example, BEW did an excellent study for
PG&E and CEC.  They found out that the risk of an island occurring on
the PG&E system with high penetration PV was something like once every
3000 years. 
 
Best Regards,
 
John Berdner

>>> sky at ecologicalsystems.biz 1/11/2008 07:09:53 PM >>>

"Think 5 year old hanging off the wiring jungle gym style. I have
asked
many wrenches out there if that image is ok in their minds and I have
not found one yet that thinks it is."

The image this statement paints tells me its time to shut off all the
power coming into our homes from the Utility companies. 

I think its criminal to hold the solar industry to a higher standard
than any of the other power trades. 

That's what this new code does. A 5 year old child can hang on a power
line coming in from the street that's not in conduit but is anyone
pointing that out? The power line is often capable of putting out 500
amps or more on 2 or more legs. Compared to Solars less than 5 amps
typical per leg under load.

Outlets in peoples homes are subject to 5 year olds putting forks in
them and typically put out more than 20 amps.

The people that wrote this new code are a bunch of standards raising
saboteours of the solar industry. Single handedly raising the cost of
solar installations by another 10%. I know Berdner and others are
fighting hard against these anti solar code changes but we're clearly
losing.

There has to be a better balance struck between existing allowable
methods for all other power sources and those allowed for solar. This
technology is innately benign and we need to push harder for true plug
and play. 

Of course when its all said and done it's the poor and middle class
that
gets hurt by the higher standards placed on solar, because the cost
moves that much further out of their reach and the air quality
continues
to go down across the country. And another hundred thousand people
suffer from the effects of carbon monoxide poisoning in the home.

My 2 cents,
Sky Sims
Ecological Systems
www.ecologicalsystems.biz 
220 County Road 522
Manalapan, NJ 07726
ph)732-462-3858 fax)732-462-3962

-----Original Message-----
From: John Berdner [mailto:jberdner at sma-america.com] 
Sent: Tuesday, January 08, 2008 5:31 PM
To: RE-wrenches at topica.com 
Subject: RE: Evolution of the Quick connect [RE-wrenches]


Phil / Wrenches:

I was involved with some of the discussions with J. Wiles, W. Bower
and
R. Wills on 690.31 (A). 2008 690.31(A) was added to deal with the
situation of an untrained person, a small child for example, being
able
to walk up to a ground or pole mounted array and grabbing onto single
conductor cables. Even assuming locking connectors it could be
possible
to pull the wire out of a terminal box or break the wire. This could
result in live conductors and or possible arcing during the load break.



Think 5 year old hanging off the wiring jungle gym style. I have asked
many wrenches out there if that image is ok in their minds and I have
not found one yet that thinks it is.

The key phrase in 690.31(B) is "readily accessible". Rooftop PV for
example is not considered readily accessible under the NEC unless
there
is roof access from an unlocked door, rooftop at ground level, etc. 
Even if you have a ground mounted array you can make the wiring not
"readily accessible". Building a fence or putting a cover on the back
of the array, expanded metal mesh for example. Access to the wiring
then would require you to unlock the gate or remove the metal mesh
with
a tool before you could gain access to the wiring thereby making the
wire no longer readily accessible. I would expect that the structure
and/or module guys will come up with some innovative solutions fairly
soon that meet the requirement at relatively low cost.

This requirement is independent of the locking connector requirement.

I hope that helps shed a little light.

Best Regards,

John Berdner



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