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.
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
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.
Hopefully there will be more information later.
Nick
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
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.
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.
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...
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.
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
Or at least a clarification of any risks that may be present.
Brian
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
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.
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).
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 ?
Is the upshot of this that houses with solar panels will end up paying increased insurance premiums ?
Yep without incoming mains the invertor shuts down, but if the sun is shining on the panels they don't shut down...
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...
WE can but hope so :-)
They are usually there to disconnect neon signs.
Colin Bignell
That would be FITting.
I've seen on places that don't have neon signs... One for Adam.
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.
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