OT Firemen unable to tackle fire effectively due to solar panels on roof


C

Chris Hogg

http://www.bbc.co.uk/news/uk-england-devon-22439099

John Chalk from the fire service said: "There were solar panels on the
roof which meant in effect we still had a live supply of electricity
to the building, so we weren't able to get into the building. It meant
the fire developed much more rapidly than we would have liked."

One wonders if an electrical fault in the solar panel wiring actually
caused the fire in the first place.
 
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M

Man at B&Q

http://www.bbc.co.uk/news/uk-england-devon-22439099

John Chalk from the fire service said: "There were solar panels on the
roof which meant in effect we still had a live supply of electricity
to the building, so we weren't able to get into the building.
What was stopping them, FFS? how do thay manage in any other building,
without solar panels, such as a house where the main fuse and isolator
are in the house?

"A fire service spokesman said an investigation into the cause of the
blaze would begin on Wednesday." I hope that's followed by an
investigation into the behaviour of the fire service.

MBQ
 
R

RobertL

Perhaps they thought that the panels run at 230v AC
Don't these PV panel arrays run at 100+ Volts DC which would be more dangerous to a fireman than an AC power supply.

Robert
 
N

newshound

Perhaps they thought that the panels run at 230v AC or maybe there are
some other factors not mentioned in the report - such as a petrol
generator suspended from the ceiling.
(http://www.bbc.co.uk/news/uk-scotland-tayside-central-21770421)

Hopefully there will be more information later.

Nick
Normally, there is a readily accessible isolator for the incoming mains
right by the front door. I suppose their concern is that the panels
could be charging batteries connected to an inverter in the attic or
somewhere otherwise inaccessible (particularly if it was DIY'd).

So while I half agree that it seems a slightly "wussy" statement from
the fireman I can also half see his point. And it would have been the
local guy in charge who would have been in the dock if one of the
firemen had got zapped.
 
Perhaps they thought that the panels run at 230v AC or maybe there are
some other factors not mentioned in the report - such as a petrol
generator suspended from the ceiling.
(http://www.bbc.co.uk/news/uk-scotland-tayside-central-21770421)

Hopefully there will be more information later.

Nick
The panels run at about 40V DC and are daisy chained to give upto about
700V DC.

The DC runs in extra thick insulated cable to the inverter that makes it
230V AC.
The AC side will shut down as soon as grid power is lost.
The DC side will then rise about 10% in voltage as no current is being
drawn.

I can't see any real extra danger for the fire fighters as the DC side
tends to be in weather proof connectors and it doesn't matter if they
get wet.
 
D

Dave Liquorice

Normally, there is a readily accessible isolator for the incoming mains
right by the front door.
Some commercial places have external "Firemans Switches" not sure what
they do but one would assume they are in the supply before any
distribution. Domestic well, there are 3 lots of CU's here only one is
"by the front door". The other two are in a windowless room in the middle
of the building.

I also wonder how much affect having the entire roof covered in panels
stopped them breaking into the roof from outside and kept the water out
where the fire had broken through as well...
So while I half agree that it seems a slightly "wussy" statement from
the fireman I can also half see his point. And it would have been the
local guy in charge who would have been in the dock if one of the
firemen had got zapped.
The Fire Service do come up with some "odd" reasons for not doing what
one would expect based on Health & Safety of the firemen at times.
 
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B

Brian Gaff

I was under the impression that the invertors was wired in such a way that
if the main switch was off it stopped as well. To work any other way would
be downright dangerous in myy view. the panels themselves generate low
voltages so should be disregarded.

Brian
 
B

Brian Gaff

Or at least a clarification of any risks that may be present.

Brian

--
Brian Gaff....Note, this account does not accept Bcc: email.
graphics are great, but the blind can't hear them
Email: (e-mail address removed)
______________________________________________________________________________________________________________


http://www.bbc.co.uk/news/uk-england-devon-22439099

John Chalk from the fire service said: "There were solar panels on the
roof which meant in effect we still had a live supply of electricity
to the building, so we weren't able to get into the building.
What was stopping them, FFS? how do thay manage in any other building,
without solar panels, such as a house where the main fuse and isolator
are in the house?

"A fire service spokesman said an investigation into the cause of the
blaze would begin on Wednesday." I hope that's followed by an
investigation into the behaviour of the fire service.

MBQ
 
M

Man at B&Q

I was under the impression that the invertors was wired in such a way that
if the main switch was off it stopped as well. To work any other way would
be downright dangerous in myy view. the panels themselves generate low
voltages so should be disregarded.
If the external mains fails then inverters *have to* shutdown,
otherwise they will power a "power island" which will be potentially
fatal to anyone investigating the supposedly dead mains.

MBQ
 
M

Martin Brown

Or at least a clarification of any risks that may be present.

Brian
I have known the fire brigade let an entire lab block burn down because
there was sodium metal in the lab. We worked out that there was about
100g at most, but that small misunderstanding caused severe devastation.

I think they have reported before that they are wary of fires in the
roof space of buildings with solar panels because the panel side stays
seriously hot as in hundreds of volts DC when open circuit in sunlight.
High voltage and moderate current is more efficient but has its
drawbacks if the cables insulation gets compromised in a fire.

Contact with such high DC voltages would definitely spoil your day.

The inverters should always shut down when mains is not present.
 
N

newshound

I have known the fire brigade let an entire lab block burn down because
there was sodium metal in the lab. We worked out that there was about
100g at most, but that small misunderstanding caused severe devastation.

I think they have reported before that they are wary of fires in the
roof space of buildings with solar panels because the panel side stays
seriously hot as in hundreds of volts DC when open circuit in sunlight.
High voltage and moderate current is more efficient but has its
drawbacks if the cables insulation gets compromised in a fire.

Contact with such high DC voltages would definitely spoil your day.

The inverters should always shut down when mains is not present.
Interesting.

So what's the fix? Spray a blanket of foam over the panels before doing
anything else, at least in daytime?

Use high pressure hoses to disrupt the panels first?

Require a fire-resistant engineered device to "crowbar" the panels when
tripped manually or by fire? That's the sort of thing which gets imposed
on nuclear power plant (we call it defence in depth).
 
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D

Dave Liquorice

I was under the impression that the invertors was wired in such a way
that if the main switch was off it stopped as well. To work any other
way would be downright dangerous in myy view.
Yep without incoming mains the invertor shuts down, but if the sun is
shining on the panels they don't shut down...
the panels themselves generate low voltages so should be disregarded.
Er, no several hundred volts DC with a fair bit of energy behind 'em.

Think about it. Take a normal 4 kWp "domestic" array say at 50 V that
would require 80 A, not impossible to handle but I^2R losses in cables or
joints become significant. Make the panels 500V DC (which they are ish)
and it drops to a much easier to handle 8 A.

That hotel looked to have some what larger tah 4 kWp array...
 
T

The Natural Philosopher

Is the upshot of this that houses with solar panels will end up paying
increased insurance premiums ?
WE can but hope so :)
 
M

Martin Brown

Does anyone remember a few years ago a fire brigade spokesman attracting
a lot of ridicule when he said that unleaded petrol was for some reason
more dangerous than leaded ?
I suppose it depends how you measure "danger".

Leaded is a lot more acutely toxic with its tetra-ethyl lead antiknock
but unleaded has a higher content of benzene and MTBE which makes it a
potential carcinogenic hazard in the longer term.

Either will be equally unforgiving and nasty in a fire.
 
H

harry

Perhaps they thought that the panels run at 230v AC or maybe there are
some other factors not mentioned in the report - such as a petrol
generator suspended from the ceiling.
(http://www.bbc.co.uk/news/uk-scotland-tayside-central-21770421)

Hopefully there will be more information later.

Nick
They could be running at up to 1000 volts. DC
Mine run at up to 750 volts. But only when the sun shines.
But they can't be turned off except by covering them.
 
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J

John Williamson

Dave said:
I've seen on places that don't have neon signs... One for Adam.
When I was working at a filling station a long time ago, I was told that
the fireman's switch cut power to the whole of the forecourt. So, pumps,
lights and any other stuff outside the main building. Basically,
anything that could cause a spark in the area of the pumps.
 
H

harry

I was under the impression that the invertors was wired in such a way that
if the main switch was off it stopped as well. To work any other way would
be downright dangerous in myy view. the panels themselves generate low
voltages so should be disregarded.

 Brian

--
Brian Gaff....Note, this account does not accept Bcc: email.
 graphics are great, but the blind can't hear them
Email: (e-mail address removed)
___________________________________________________________________________ ___________________________________
The panels always generate in sunlight. You can isolate them
but not shut them down.
 
A

ARW

John said:
When I was working at a filling station a long time ago, I was told
that the fireman's switch cut power to the whole of the forecourt.
So, pumps, lights and any other stuff outside the main building.
Basically, anything that could cause a spark in the area of the pumps.
Would it surprise you that pub beer cellars seem to have more stringent
electrical regs than a petrol station?
 
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P

polygonum

Would it surprise you that pub beer cellars seem to have more stringent
electrical regs than a petrol station?
Never seen a beer cellar at a petrol station...

Oh! I see what you mean. :)
 

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