Here is a standard, safe power-down procedure you can include in your First Choice Solar customer handover packs.
The order of these steps is critical. Shutting down the AC side before the DC side ensures the inverter is no longer under load, which prevents dangerous electrical arcing when disconnecting the high-voltage solar arrays.
1.Turn off the battery unit:Use the physical button on the battery.
Press the main power button on the battery unit to shut it down. This prevents the battery from attempting to charge or discharge while you are disconnecting the rest of the system.
2.Switch off the AC Isolator:Usually a red rotary switch.
Locate the AC isolator switch next to the inverter, or the breaker marked "Solar/Inverter AC Supply" in the consumer unit, and turn it to the OFF position. The inverter is now disconnected from the grid and the home.
3.Switch off the PV DC Isolator:Usually a black rotary switch.
Locate the DC isolator switch for the solar panels—often found underneath or right next to the inverter—and turn it to the OFF position. This disconnects the solar panels from the inverter. This can be built directly in to most modern inverters
4.Switch off the Battery DC Breaker:
Finally, locate the separate DC isolator or breaker that sits between the battery and the inverter, and switch it to the OFF position.
5.Wait 5 minutes:Safety precaution.
The system is now fully isolated, but the inverter's internal capacitors hold a high-voltage charge. Wait at least 5 minutes before performing any maintenance or resetting the system.
Note on restarting: To power the system back up safely, the process must be done in exact reverse: Battery DC Breaker ON, PV DC Isolator ON, AC Isolator ON, and finally the Battery Unit power button ON.
