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

Mon Jan 5 14:33:59 PST 2009

I too am a volunteer and the whole thing of a panel still producing power
after an axe goes through it this; yes at first there will be DC voltage
flowing and as soon as a steel axe puts a hole in a module it will make a
serious short and that module will not be able to produce any more energy.
It is also possible that as soon as this happens the whole system will short
to ground and will blow the inverters fuse and again no power flow which has
made the system much safer to be around and although all electricity is
hazardous, DC tends to through you out or away. All this with the fact a
firefighter has gear on which is designed to be non-conductive in nature so
the chance of being "bit" by the voltage is slim.

my 2kw

On Mon, Jan 5, 2009 at 3:18 PM, boB Gudgel <bob at midnitesolar.com> wrote:

>
>  Date: Mon, 05 Jan 2009 16:07:58 -0500
>> From: Nicholas Ponzio <nponzio at buildingenergyus.com>
>>
>>
>> I just got this email forwarded from a coworker that volunteers as a
>> firefigher. Your comments are welcome:
>>
>>
>>
> I agree that fire access may be restricted, but a bunch of this report I
> would say is definitely hysteria..
>
>  Forwarded Message:
>>
>> The thing to know with solar panels are that they cannot be shut down -
>> they are ALWAYS ENERGIZED.
>>
> ALWAYS energized ?  REMOTELY possible at night if something is backfeeding
> I suppose.
>
>>  And they are energized with up to 600 volts
>> of DC current.
>>
>   600 Volts of Current, eh ?
>
>
>   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.
>>
> I suppose if the one or a few panels is more important the the whole
> house...
>
>   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.
>>
>>
> I don't think you would have 600 Amperes of Voltage after the panels have
> fallen through the roof, would you ?
> Doesn't fire shade modules ?
>
>  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.
>>
>>
>>
> Something that could be done is to short out the array at the box (Break
> before Make of course)
>
>  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.
>>
> Third time's a charm...   Is that 600 AC volts of DC current or the other
> way around ?
>
>   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.
>>
> OK, I'm starting to think that this letter belongs on SNOPES.
>
>   (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
>>
>>
>>
> This sounds reminiscent of  those first letters regarding  NEC Wind  in the
> state of Washington from L&I.
>
> I think they really need to re-think their wording just a little bit.
>
> Merry New Year !
> boB
>
>
>
>
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-- 
Jason Lombard
Open Hand Solar LLC.
Certified Sustainable Building Adviser
openhandsolar at gmail.com
505 795 8646

"I'd put my money on solar energy… I hope we don't have to wait 'til oil and
coal run out before we tackle that."

—Thomas Edison
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