Hi William (and any other person who wishes to describe themselves as
professional (designer, installer, etc.)),
Please accept this note as confirmation that your evangelism on wire
management has not fallen on entirely deaf ears.
Additionally, I'm curious how the practice of requiring a ten year
equipment warranty squares with the acceptance of plastic wire ties.
Sincere thanks from one convert,
Bill Loesch
Solar 1 - Saint Louis Solar
On Wed, Nov 13, 2013 at 3:41 PM, William Miller wrote:
Bill:
I respectfully disagree with your logic: Define "perfectly
installed." If
your connections are tight and permanent and the conductors are
protected
from damage, you have a great chance of a reliable, safe lifetime of
service. How can you guarantee that your leads will stay protected
after
the ties fail? Studies show that even UV resistant wire ties will
fail well
before the life expectancy of the system has expired. When the ties
fail,
your PV leads are hanging on the roof. Even before the ties fail,
rodents
can chew on them. Conduit was invented for a reason and we should be
using
it.
I agree that arc-fault breakers will improve the situation, but I
don't
think any form of OCPD is a substitute for good wiring practices. I
think
wire protection is just as important on PV circuits as it is on any
other
high voltage circuit. Try getting away with wiring a rooftop air
conditioning unit by tying the conductors to some metal framework with
plastic ties and see how long it takes to get red-tagged by your local
inspector.
I suspect we've gotten to where we are on lax wire protection
standards for
two reasons:
1. In the early days, PV was low voltage, 12 to 24 volts, and was
treated
as such, even though current capabilities exceeded that of
conventional low
voltage thermostat, door-bell and telephone wiring.
2. It is my understanding that PV wiring standards in Europe are
not
stringent, and European demand drove the PV market for many years.
Products
were built to satisfy the European market and US standards had to work
with
the equipment available.
Some would say: "if it is under the array, it is protected." We have
seen
PV wire getting damaged under arrays and it is possible to get damaged
under
BPIV components as well. I believe that protecting PV wire is more
important than protecting conventional AC circuit wiring because PV
circuits
are more prone to create and sustain arcing.
Some say that protecting PV wire in conduits will add too much expense
to PV
installations. Consider the cost of fires and, inevitably, injuries
and
deaths. One news story about an obscure, rarely used product is
already
causing many of us headaches. Statistically, it is inevitable that
more
accidents will happen. I don't want that on my conscience.
I would suggest that we need to expand the discussion beyond fire
hazards.
I also worry about electrocution hazards in high voltage PV circuits.
Good
wire protection is essential in preventing contact with high voltages.
Unprotected PV wiring is an irresponsible practice. I am fighting an
uphill
battle to develops methods to protect PV wiring because the industry
is not
helping at all. The trend has been to make it harder to protect
wiring.
This trend will result in accidents. I think we should do better.
Sincerely,
William Miller
From: re-wrenches-boun...@lists.re-wrenches.org
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Bill
Brooks
Sent: Monday, November 11, 2013 3:38 PM
To: 'RE-wrenches'
Subject: Re: [RE-wrenches] RE-wrenches Digest, Vol 6, Issue 423
William and David,
This particular problem goes away with arc fault detection. The longer
we
wait to introduce arc fault detection into our systems, the more we
will
have opportunities for news reports such as the one William brings
forward.
Wire ties are not the problem. Could a wire tie cause a problem-sure,
just
like anything improperly installed.
At the end of the day, you can a have a perfectly installed system,
but if
it does not have arc fault detection and high resolution ground fault
detection, it can still catch on fire. You have no control over
product
failures other than buying from large companies that can actually
insure
their products in a failure.
Fires are not that common, but it didn't take much to get all the
viewers of
this news report up in arms did it?
Bill.
------------------------------
_______________________________________________
List sponsored by Home Power magazine
List Address: RE-wrenches@lists.re-wrenches.org
Change email address & settings:
http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
List-Archive:
http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
List rules & etiquette:
www.re-wrenches.org/etiquette.htm
Check out participant bios:
www.members.re-wrenches.org
_______________________________________________
List sponsored by Home Power magazine
List Address: RE-wrenches@lists.re-wrenches.org
Change email address & settings:
http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
List rules & etiquette:
www.re-wrenches.org/etiquette.htm
Check out participant bios:
www.members.re-wrenches.org
