[RE-wrenches] fire safety vs. fire hysteria?

[Nicholas Ponzio]

I just got this email forwarded from a coworker that volunteers as a 
firefigher. Your comments are welcome:

Forwarded Message:

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.

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.

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.
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.

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.

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)
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.

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!"

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.

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.


<End Forwarded Message>

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. "

And are there documented cases where firefighters let a house burn 
because it had PV on the roof?

Thanks again,
nik

-- 


Nicholas Ponzio
Building Energy
1570 South Brownell Road
Williston, VT 05495

t: 802-859-3384 x15
f: 802-658-3982
www.BuildingEnergyVT.com

"Building Solutions for a Sustainable Future"