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<font size=3>Nik:<br><br>
Ian Woofenden mailed me the same letter which has apparently been
circulating on the internet of late. Ian asked for my response for
a potential column or at least a reply to a letter to the editor for Home
Power. Below is what I wrote back. If I missed any points, I
appreciate any feedback from my colleagues.<br><br>
There are valid concerns, in my opinion, that exist about fire fighter
safety. Unfortunately, the letter you forwarded is only partly
rational. In California, there are competing Fire Departments that
are attempting to create regulations for PV installs to accommodate fire
fighter safety concerns. The two top agencies are the Cal Fire and
the LAFD. Preliminary documents from both agencies are on our web
site under resources:
<a href="http://mpandc.com/resources/resources.html" eudora="autourl">http://mpandc.com/resources/resources.html</a>
They are near the top of the list.<br><br>
The implications of the roof edge set backs are severe. We did a
quick analysis of the 20 jobs we did previous to the issuance of these
preliminary standards and, of the residential jobs, about 90% would be
infeasible with the new setbacks.<br><br>
One of the agencies, I recall it was the LAFD, allowed quick release
hardware to suffice if minimum setbacks could not occur. We created
some concepts for quick release mounting and presented them to DPW, but
they never contacted us back. As more and more jurisdictions
require setbacks, I am hoping some manufacturer can take these concepts
and create a product that will allow installations closer to the roof
edges than either of the above requirements would allow.<br><br>
This is a topic that will be very important in the next year.
Thanks for brining it up.<br><br>
William Miller<br><br>
Ian:<br><br>
The firefighters letter states facts for the most part. The two
areas I disagree with is the length of time that a PV feeder remains
energized after being tarped and the presence of PV feeder voltages at
night. The time required for covered PV modules to de-energize
should be no greater than five minutes by statute and confirmed by
independent lab testing. After sunset PV voltage will not be
present.<br><br>
The 2005 National electrical code addresses these safety issues as
related to fire fighters by requiring the PV feeders either have a
disconnect located prior to the feeder entering the building envelope or
the feeders need to be inside a metallic conduit. I believe future
code editions may further improve safety by requiring minimum spacing
below roof surfaces for this conduit to be installed.<br><br>
Firefighters can be assured of safety from PV voltage hazards if they
follow two rules (in addition to turning off any disconnects
provided): 1. Do not break the modules, and 2. Do not cut through
metallic conduits. I can not comment on the likelihood of
electrocution by voltages following a stream of water, but I am sure
there is information out there on this issue.<br><br>
Ian, I hope this answers your questions. Please feel free to
reformat this to fit your needs. If my name will be on it, run it
by me for review.<br><br>
William Miller<br><br>
<br>
At 01:07 PM 1/5/2009, you wrote:<br>
<blockquote type=cite class=cite cite>I just got this email forwarded
from a coworker that volunteers as a firefigher. Your comments are
welcome:<br><br>
Forwarded Message:<br><br>
At this past Monday's Twp. Chief's meeting, I went to the presentation
put on by the State of NJ last night at Amwell Valley Fire concerning
solar panels and the danger they present to the Fire Service.<br><br>
The presentation lasted for about 2 1/2 hours and was what I believe time
well spent. It really opened my eyes to the potential danger and
problems they will be for us for any dwelling fire we will encounter
where they are present. I'm going to attempt to give everyone a
quick snapshot of what was covered.<br>
<br>
The thing to know with solar panels are that they cannot be shut down -
they are ALWAYS ENERGIZED. And they are energized with up to 600
volts of DC current. For example, you cannot put an ax through them
to open up a roof to vent - your putting the ax through 600 volts.
If fire is infringing upon solar panels on the roof it will compromise
the integrity of the panels. You then have 600 volts of live
electrical energy - and what don't you do when you have live electrical
energy? - you don't put water on it. Even if the roof burned
through and the panels fell into the structure, unless the panels were
destroyed (de-energized) by the fire and/or falling into the structure,
they can still have the potential to be live,they have to be
treated as such and have the potential of 600 volts of DC current.<br>
A basic solar system consists of: The solar panels themselves; a
combination box; a disconnect box; and a inverter. The panels all
feed into a combination box. The combination box (which is almost
always located on the roof) takes in all the energy and sends it to a
disconnect box. The disconnect box takes the energy and then sends
it into the inverter which converts the DC current into AC current.
>From there the AC energy "pushes" into the structure's normal
electrical system.<br><br>
The combination box has fuses in it that come from the solar panels
themselves. If you access that box, you can pull all the fuses
inside and "kill" anything after the combination box. But
remember the panels are still live and have up to 600 volts in
them. If you "kill" the energy at the disconnect box -
anything up to that box is still energized - the solar panels, the
combination box, the line going from the combination box into the
structure and into the disconnect box are all still energized. The
power company pulling the meter for normal service has no effect
whatsoever on the solar panel system - it is all still live and has up to
600 volts of DC current. The only "good" thing when it
comes to the disconnect box and the inverter is that they need to be
co-located with the normal service panel for the structure and each
should be marked as appropriate.<br><br>
Even if it's nighttime and the solar panels have not been exposed to
direct sunlight for several hours, they still are energized and can kill
you. It is estimated that the panels would need to be covered with
an opaque tarp for 7-10 days before the panels will
"de-energized" down to minuscule levels. (although the
handouts specify that this is an option for safety steps - it is not
accurate per the presenter)<br>
In closing there are people who have greater minds and resources than we
do in developing a process to safely handle fires which may involve these
systems - such as the NFPA, OSHA, etc. Per the presenter, the
situation - and these organizations, are now starting to become aware of
the potential problems. So far in the State of NJ, there is no
recorded injury to a Firefighter being caused by coming into contact with
a solar panel system. Ironically, New Jersey comes in 2nd when it
comes to solar panel system installations in the nation, behind
Califorina.<br><br>
The final question which was asked really put things in prospective -
someone asked that since Califorina is number one when it comes to Solar
Panel Syatem installations, "...what do their Firefighters do when a
structure fire involves these systems?" Answer was "...
they let it burn!"<br><br>
Please, I'm not suggesting that we adopt this strategy. But the
reality is - I really don't have an answer and it seems as if the Fire
Service industry, nor the Solar Panel Companies, don't either.<br><br>
Just - please be aware and please be careful if you roll up to a
structure where a solar panel system is installed - bottom line, if can
kill you.<br><br>
<br>
<End Forwarded Message><br><br>
Is this even possible? "Even if it's nighttime and the solar panels
have not been exposed to direct sunlight for several hours, they still
are energized and can kill you. It is estimated that the panels
would need to be covered with an opaque tarp for 7-10 days before the
panels will "de-energized" down to minuscule levels.
"<br><br>
And are there documented cases where firefighters let a house burn
because it had PV on the roof?<br><br>
Thanks again,<br>
nik<br>
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