kingpb
Senior Member
- Location
- SE USA as far as you can go
- Occupation
- Engineer, Registered
Does a properly labeled emergency off pushbutton that shunt trips the PV combiner panel mains suffice for disconnecting the PV system for a commercial build?
What code cycle are you in? If you are operating under the 2020 NEC, then no, you have to have rapid shutdown at the PV modules. You have to get the maximum DC voltage down to 80V or less between any two conductors within the array boundary within 30 seconds of RSD initiation.Does a properly labeled emergency off pushbutton that shunt trips the PV combiner panel mains suffice for disconnecting the PV system for a commercial build?
Who is the intended user of the disconnect, and what is its application? Many utilities require an open blade disconnect, so that they can open the enclosure door and see that the blades are disconnected. Is this for rapid shutdown, or for the utility, or both? It is common that the utility disconnect doubles as the point of rapid shutdown initiation.Does a properly labeled emergency off pushbutton that shunt trips the PV combiner panel mains suffice for disconnecting the PV system for a commercial build?
If you are operating under the 2020 NEC, then no, you have to have rapid shutdown at the PV modules.
Suffice for what? There are various different requirements for disconnecting means in the NEC, and then the utility will probably have some on top of those.Does a properly labeled emergency off pushbutton that shunt trips the PV combiner panel mains suffice for disconnecting the PV system for a commercial build?
From the context of the question I assumed that he was asking about conventional strings connected to a string inverter through a DC combiner with contactors deactuated by a pushbutton switch at ground level, not module level rapid shutdown. That would work for earlier code cycles but not for the 2020 NEC and possibly not for the 2017 NEC, either.Most module-level rapid shutdown methods with which I'm familiar, can initiate the shutdown as a result of either shutting off the power to the inverter(s) as is the case microinverters or the SolarEdge system, or by shutting off the power to the device that controls the module-level devices (Tigo RSS or Tigo CCA/TAP)
For rapid shutdown.From the context of the question I assumed that he was asking about conventional strings connected to a string inverter through a DC combiner with contactors deactuated by a pushbutton switch at ground level, not module level rapid shutdown. That would work for earlier code cycles but not for the 2020 NEC and possibly not for the 2017 NEC, either.