Back feed thru a fusible disconnect

[rick1]

No they do not. They have fire axes, and one of the first things they do when they pull up to a house fire with solar panels is smash every solar panel with a fire axe. It is the only way to turn them off.

I am trying to envision firefighters climbing onto two story snow and ice covered roof with fire coming out of it and fire axing up to 40 solar panels before the roof caves in and they all parish.

[SunEagle]

I am trying to envision firefighters climbing onto two story snow and ice covered roof with fire coming out of it and fire axing up to 40 solar panels before the roof caves in and they all parish.

Well if have you have panels without a way to totally disconnect their power leads then set a fire and you will see for yourself. There has been more than one occasion that someone got shocked by solar panels due to the lack of a disconnecting means. It is now a code requirement.

[Naptown]

Well if have you have panels without a way to totally disconnect their power leads then set a fire and you will see for yourself. There has been more than one occasion that someone got shocked by solar panels due to the lack of a disconnecting means. It is now a code requirement.

The issue is the panels are on the roof. Disconnect must be accessible (near the meter)
Fire department shows up and turns off the disconnect. Now DC power is off to the inverter but is still alive and well on the roof from the panels to the disconnect. the only way to turn off the voltage would be to either cover them or short the entire array out which would drop the voltage to 0
However the fire department isn't going to do that.

[SunEagle]

The issue is the panels are on the roof. Disconnect must be accessible (near the meter)
Fire department shows up and turns off the disconnect. Now DC power is off to the inverter but is still alive and well on the roof from the panels to the disconnect. the only way to turn off the voltage would be to either cover them or short the entire array out which would drop the voltage to 0
However the fire department isn't going to do that.

If there is no way to disconnect the panels and isolate the power from them the FD is not going to risk the chance of electrocution to anyone using a hose to put out the fire. Trust me when I say the FD will find a way to make sure there is no live power cable anywhere they are working. I have seen the FD in action and they will find a way to de-energize all power feeds to a building before they will try to put it out with water. If that means tearing the panels off the roof using their ladder truck then so be it. If they can't find a way to kill all power then unless there is someone that needs to be rescued they will let the building burn. It is for their own safety.

People first, property second. I believe Sunking when he states they will use their axes on the panels.

[Naptown]

If there is no way to disconnect the panels and isolate the power from them the FD is not going to risk the chance of electrocution to anyone using a hose to put out the fire. Trust me when I say the FD will find a way to make sure there is no live power cable anywhere they are working. I have seen the FD in action and they will find a way to de-energize all power feeds to a building before they will try to put it out with water. If that means tearing the panels off the roof using their ladder truck then so be it. If they can't find a way to kill all power then unless there is someone that needs to be rescued they will let the building burn. It is for their own safety.

People first, property second. I believe Sunking when he states they will use their axes on the panels.

So you would take a metal object and start smashing live electrical parts? potentially exposing live electrical parts?
Letting the building burn is more like it. If the building is that engulfed it is pretty much too late anyway.

[SunEagle]

So you would take a metal object and start smashing live electrical parts? potentially exposing live electrical parts?
Letting the building burn is more like it. If the building is that engulfed it is pretty much too late anyway.

I think the FD (which I am not one of) would first try to kill all power to the burning building no matter what is it constructed of. If they can't guarantee that all power is off then they probably would just let it burn. It doesn't have to be fully engulfed but if they only have water as a suppressant they won't pour it on an energized circuit. It's too dangerous to them.