Rapid Shutdown alternative

Status
Not open for further replies.

csoc64

Senior Member
Location
northeast
Installing a Solaredge 3 phase system using one 14.4K US and one 9K US. All equipment is located in the middle of a commercial building and I am trying to avoid having to run a full set of conductors to and from the RSD on the outside of the building. I do not have much experience with contactors, but was wondering if it would be possible to install a 3 phase contactor in-line at the equipment location and run some kind of push button actuator to the outside that would open the contactor when initiated. Contactor would need to be 100A rated for my circuit size. Any other ideas would be appreciated.
 

ggunn

PE (Electrical), NABCEP certified
Location
Austin, TX, USA
Occupation
Electrical Engineer - Photovoltaic Systems
Installing a Solaredge 3 phase system using one 14.4K US and one 9K US. All equipment is located in the middle of a commercial building and I am trying to avoid having to run a full set of conductors to and from the RSD on the outside of the building. I do not have much experience with contactors, but was wondering if it would be possible to install a 3 phase contactor in-line at the equipment location and run some kind of push button actuator to the outside that would open the contactor when initiated. Contactor would need to be 100A rated for my circuit size. Any other ideas would be appreciated.
Is there no service disconnect on the outside of the building? How are firefighters to de-energize the utility service conductors?
 

csoc64

Senior Member
Location
northeast
Is there no service disconnect on the outside of the building? How are firefighters to de-energize the utility service conductors?
800A service disconnect and utility meter are both inside at the same location as the inverters. Definitely atypical. My guess is that firefighters will wait for a service disconnect at the street before going in.
 

ggunn

PE (Electrical), NABCEP certified
Location
Austin, TX, USA
Occupation
Electrical Engineer - Photovoltaic Systems
800A service disconnect and utility meter are both inside at the same location as the inverters. Definitely atypical. My guess is that firefighters will wait for a service disconnect at the street before going in.
That would take care of rapid shutdown. You do by code have to have a rapid shutdown initiation switch, but unless it is a one or two family dwelling the 2020 NEC does not require it to be on the outside of the building. The code also says the initiation switch can be either a PV AC disconnect or the service disconnect.
 

csoc64

Senior Member
Location
northeast
That would take care of rapid shutdown. You do by code have to have a rapid shutdown initiation switch, but unless it is a one or two family dwelling the 2020 NEC does not require it to be on the outside of the building. The code also says the initiation switch can be either a PV AC disconnect or the service disconnect.
Agreed on all points. This specific requirement (outside at a specific location) comes from the fire department and they do not bend.
 

ggunn

PE (Electrical), NABCEP certified
Location
Austin, TX, USA
Occupation
Electrical Engineer - Photovoltaic Systems
Agreed on all points. This specific requirement (outside at a specific location) comes from the fire department and they do not bend.
It's silly to require a PV RSI switch to be on the outside of the building but not the utility service disconnect. When would firefighters ever want to initiate rapid shutdown while leaving the building energized?

I guess I would use normally open contactors on the AC interconnection conductors with a 24VDC power supply to power them and low voltage DC lines to an interrupting button on the outside wall. You do not want to put the contactors on the DC lines; that would defeat the bleed down of the DC that SE inverters do to get the voltage down fast enough to be RSD compliant.
 

pv_n00b

Senior Member
Location
CA, USA
It's pretty common to have the service disconnect inside an electrical room in a commercial building. I'm surprised if I find one outside :)
I've come across this before, the AHJ wants an outside RSD initiator and the disconnect is inside. With SE just install the Firefighter Gateway and an emergency stop switch outside and you are good to go.
 

csoc64

Senior Member
Location
northeast
It's pretty common to have the service disconnect inside an electrical room in a commercial building. I'm surprised if I find one outside :)
I've come across this before, the AHJ wants an outside RSD initiator and the disconnect is inside. With SE just install the Firefighter Gateway and an emergency stop switch outside and you are good to go.
This would be an outstanding solution! Do you know if this device works across the board for all SE inverters? I don't recall seeing it as one of the RSD options in installation manual...
 

pv_n00b

Senior Member
Location
CA, USA
This would be an outstanding solution! Do you know if this device works across the board for all SE inverters? I don't recall seeing it as one of the RSD options in installation manual...
It uses the RS485 channel to control the inverters so it probably works on all that have an RS485 port. But best to verify with SE about a specific inverter.
 
Status
Not open for further replies.
Top