How 'Rapid Shutdown' works?

[再生可能 エネルギー]

I noticed this 'Rapid Shutdown' label. Could someone explain to me:

- how 'Rapid Shutdown' works?

- what components are needed?

- does this system is mandatory?

- does having the panels mounted vertically against a wall has different rules than installed flat on a roof?

Also I tried to understand if any components used need to be powered, if installed on the roof near the PVs?

There is no shutdown button, so can this be triggered remotely,
for example how a fireman, or a roofer, could shutdown a 'Rapid Shutdown' line before walking on a roof?



Here are some additional pictures of the inverter connected to the grid and located on the side of the house,
in case this could provide some additional information to answer to my 'Rapid Shutdown' question. Thank you.

 

[FilterGuy]

- how 'Rapid Shutdown' works?

There is no shutdown button, so can this be triggered remotely,
for example how a fireman, or a roofer, could shutdown a 'Rapid Shutdown' line before walking on a roof?

There are many different ways Rapid shutdown is implemented.

I see you have Enphase micro-inverters and that makes meeting the rapid shut-down very easy. The Micro-inverters are designed to be hooked directly to the grid so they must shut down as soon as the grid shuts down (Or the AC line to them is shut off). Since the Micro inverters are fed by only one panel the voltage on the PV side is low enough that it already meets the voltage requirement for after the shutdown. In short, on your system the AC disconnect is the rapid shutdown 'button'.

- what components are needed?

On a micor-inverter system like yours, no extra components are needed.

- does this system is mandatory?

For panels installed on the roof, there have been rapid shutdown requirements since the 2017(?) version of the NEC.

- does having the panels mounted vertically against a wall has different rules than installed flat on a roof?

I do not know.

Also I tried to understand if any components used need to be powered, if installed on the roof near the PVs?

The micro-inverters are powered by the panels so there is no 'external' power source needed.