Posted by Dino on November 21, 2011, 4:30 pm
On Sun, 20 Nov 2011 15:41:43 -0500, "Mho"
>Then arrives the Insurance company scenario in the last year. After watching
>FireFighters refuse to pour water on fires with PV panels on the roof the
>insurance companies are starting to take notice and things are in the works.
This looks stupid, with PV grid connected it is sufficient
to open the main breaker and isolate the PV system from the
grid system. Furthermore a correctly designed PV system
shall include a DC breaker with fuses to isolate the panels
from DC//AC converter.
The firefighters could then operate without any risk.
Dino
Posted by Mho on November 21, 2011, 6:46 pm
I doubt you will get up on the roof and cover up the live panels so they
are safe for the Firefighter's water hoses?
Even if you cut the leads off the PV panels, it wouldn't matter.
Think again. You missed the point.
-------------
This looks stupid, with PV grid connected it is sufficient
to open the main breaker and isolate the PV system from the
grid system. Furthermore a correctly designed PV system
shall include a DC breaker with fuses to isolate the panels
from DC//AC converter.
The firefighters could then operate without any risk.
Dino
Posted by argusy on November 22, 2011, 10:55 am
On 22/11/11 3:00 AM, Dino wrote:
> On Sun, 20 Nov 2011 15:41:43 -0500, "Mho"
>>
>> Then arrives the Insurance company scenario in the last year. After watching
>> FireFighters refuse to pour water on fires with PV panels on the roof the
>> insurance companies are starting to take notice and things are in the works.
> This looks stupid, with PV grid connected it is sufficient
> to open the main breaker and isolate the PV system from the
> grid system. Furthermore a correctly designed PV system
> shall include a DC breaker with fuses to isolate the panels
> from DC//AC converter.
> The firefighters could then operate without any risk.
> Dino
You've left out a bit, Dino.
I agree about disconnecting the inverter, and disconnecting the mains from the
inverter. (That's my system btw)
That still leaves, say, eight panels wired up and if one end gets grounded by a
bare burnt cable - there's the other end, still connected, and possibly bare
wire if that fire has done a good job on the insulation, through 8 or more
panels on a sunny day and a raging fire underneath.
That could conceivably be a source of a voltage/current sufficient to kill a
fireman, acting as a conduit back to ground through a stream of water
I know that that scenario is highly improbable, but if I was a fireman, I'd
certainly not take that risk!!
Also, if I've got a fire in my house, there's no way I'd go where there's a
bloody big rising heat source, to separate all those panels.
Let it burn. I just hope my insurance has been changed to consider that, on the
day I have a fire in the house.
Graham
Posted by Dino on November 22, 2011, 1:34 pm
On Tue, 22 Nov 2011 21:25:23 +1030, argusy
>On 22/11/11 3:00 AM, Dino wrote:
>> On Sun, 20 Nov 2011 15:41:43 -0500, "Mho"
>>
>>>
>>> Then arrives the Insurance company scenario in the last year. After watching
>>> FireFighters refuse to pour water on fires with PV panels on the roof the
>>> insurance companies are starting to take notice and things are in the works.
>>
>> This looks stupid, with PV grid connected it is sufficient
>> to open the main breaker and isolate the PV system from the
>> grid system. Furthermore a correctly designed PV system
>> shall include a DC breaker with fuses to isolate the panels
>> from DC//AC converter.
>> The firefighters could then operate without any risk.
>> Dino
>You've left out a bit, Dino.
>I agree about disconnecting the inverter, and disconnecting the mains from the
>inverter. (That's my system btw)
>That still leaves, say, eight panels wired up and if one end gets grounded by a
>bare burnt cable - there's the other end, still connected, and possibly bare
>wire if that fire has done a good job on the insulation, through 8 or more
>panels on a sunny day and a raging fire underneath.
>That could conceivably be a source of a voltage/current sufficient to kill a
>fireman, acting as a conduit back to ground through a stream of water
>I know that that scenario is highly improbable, but if I was a fireman, I'd
>certainly not take that risk!!
I understand your comments, and agree about the theoretical
possibility that this might happens.
Considering double contingency and failure mode of each
component of a PV system, as you state, it is highly
improbable, as the failure mode of several appliance,
machines, cars, etc.
A risk analysis might rise attention for a modified design
to include house fire risk and how to mitigate the risk.
The decision to where spend money, insurance or improved
design is your choice.
Dino
>Also, if I've got a fire in my house, there's no way I'd go where there's a
>bloody big rising heat source, to separate all those panels.
>Let it burn. I just hope my insurance has been changed to consider that, on the
>day I have a fire in the house.
>Graham
Posted by Mho on November 22, 2011, 5:10 pm
The results will likely be accessible switching and better training for
firefighters. The game has only started.
Maybe we will be getting solidstate switchable PV panels?? Remove some 24 v
control logic signal and all the silicon PV shuts itself off...LOL
"Watch this! I'm hacking the control signal for the neighbour's solar
panels. He'll get up on Halloween morning finding his batteries dead...LOL"
------------------
On 22/11/11 3:00 AM, Dino wrote:
> On Sun, 20 Nov 2011 15:41:43 -0500, "Mho"
>>
>> Then arrives the Insurance company scenario in the last year. After
>> watching
>> FireFighters refuse to pour water on fires with PV panels on the roof the
>> insurance companies are starting to take notice and things are in the
>> works.
> This looks stupid, with PV grid connected it is sufficient
> to open the main breaker and isolate the PV system from the
> grid system. Furthermore a correctly designed PV system
> shall include a DC breaker with fuses to isolate the panels
> from DC//AC converter.
> The firefighters could then operate without any risk.
> Dino
You've left out a bit, Dino.
I agree about disconnecting the inverter, and disconnecting the mains from
the
inverter. (That's my system btw)
That still leaves, say, eight panels wired up and if one end gets grounded
by a
bare burnt cable - there's the other end, still connected, and possibly bare
wire if that fire has done a good job on the insulation, through 8 or more
panels on a sunny day and a raging fire underneath.
That could conceivably be a source of a voltage/current sufficient to kill a
fireman, acting as a conduit back to ground through a stream of water
I know that that scenario is highly improbable, but if I was a fireman, I'd
certainly not take that risk!!
Also, if I've got a fire in my house, there's no way I'd go where there's a
bloody big rising heat source, to separate all those panels.
Let it burn. I just hope my insurance has been changed to consider that, on
the
day I have a fire in the house.
Graham
>FireFighters refuse to pour water on fires with PV panels on the roof the
>insurance companies are starting to take notice and things are in the works.