NEC RAPID SHUT DOWN DEVICE
1,Application Note of certificated NEP rapid shut down with panel monitoring
Application Note: PVG-20180523 Version: 2.0
1 Executive Summary of NEP rapid shut down
PVG is the NEP rapid shut down (RSD) system solution. It has the following key features:
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PVG is designed for generic PV string/central inverters and off-grid battery charger/inverters
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PVG is certified for up to 1500Vdc system
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PVG complies with NEC 2017 and NEC 2014 690.12 on rapid shut down
This application note describes the connection and usage of the PVG system.
Featers of certificated NEP rapid shut down with panel monitoring
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Increased Safety
• Firefighter is at risk of high DC voltage
• Even the AC is shut down with AC switch, high DC voltage is still on your roof.
• NEC 2014: Rapid shutdown within 10 feet
• NEC 2017: Rapid shutdown within 1 feet
2 PVG System Component rapid shut down
PVG system consists of two parts: the RSD switch PVG-1/2/3/4 and its controller PVG-C. A BDG-256 gateway is optional, but can additional function of panel level monitoring and remote monitoring through NEPVIEWER
RSD switch PVG-1/2/3/4 is installed on the rail or at the back of PV panels. It has two pairs of inputs. One pair is for connecting PV panel. The other pair is for connecting other PVGs to form a PV string. For customers who are familiar with panel level optimizers, wiring of PVGs is identical.
PVG-1/2/3/4 can connect 1 to 4 panels respectively. There is not functional difference between PVG- 1/2/3/4. The choice is mainly for economic considerations and for convenince of installation and system design.
PVG does not inlcude PV cables. Instead, length of PV cables can be chosen depending on the system size and distance between PV panels. This provides flexibility for system design and installation. For each PV cable, the only rule is that one end of the cable should be terminated with a male MC4 or campatible connector, and the other end should be terminated with a female MC4 or compatible connector. NEP also provides fixed length PV extension cables, 1-meter and 2-meter respectively, for portrait or landscape oriented PV panels.
PVG-C is a controller that commands each PVG to disconnect or connect the corresponding PV panel to the string. Communication signal is transmitted through PV cables, and thus no additional communication wire is required. For inverters that do not discharge inverter DC link capacitors in time to comply with the NEC code, an outside bleed resistor can be controlled by PVG-C through an external control board.
For a system with only one MPPT channel, only one PVG-C is required. However, for system with multiple separate MPPT channels, each channel requires one PVG-C since communication signal cannot pass through multiple MPPT channels.
PV Guard Controller — Small Residential
Compatible with SunSpec Signaling
– PVG controller can control SunSpec compatable
RSD receivers
Support NEP RSD Signaling and Monitoring
– RSD function according to NEC 2017
– Trouble shooting RSD function in case of error – Panel level monitoring at no additional cost
ON-grid / OFF-grid switch Master / Slave switch
– System is controlled by one master controller
Relay control
– Automatic relay control signal with RSD
PV Guard Controller — Commercial/ Residential
Standard 35mm DIN Rail mount
Direct connect to 208/240/480Vac AC power
– Support Low/High Voltage Ride Through
Compatible with SunSpec Signaling
– PVG controller can control SunSpec compatible RSD
receivers
Support NEP RSD Signaling and Monitoring
– RSD function according to NEC 2017
– Trouble shooting RSD function in case of error – Panel level monitoring at no additional cost
ON-grid / OFF-grid switch
– Support off-grid RSD system
Master / Slave switch
– System is controlled by one master controller
Relay control
– Automatic relay control signal with RSD
2,Rapid shutdown device sepecification
3, details of fire switch off rapid shut down RSD for NEC2017
4, installation of certificated NEP rapid shut down with panel monitoring