What are some payback times for systems currently installed? - Page 2

 On Sun, 20 Nov 2011 15:41:43 -0500, "Mho"


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

  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.


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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

 On 22/11/11 3:00 AM, Dino wrote:

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

 On Tue, 22 Nov 2011 21:25:23 +1030, argusy


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

 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"

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On 22/11/11 3:00 AM, Dino wrote:

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