SMA E-Panel installation manual
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Below are some of the new requirements for NEC 2014.
In short, there is a requirement for a “Rapid Shutdown”. This is accomplished nicely with the MidNite Solar
Birdhouse, Disco Combiners and MNBDM Battery Disconnect Module (located in the E-Panel).
Where there is more than one source of power this is even more critical. Consider a system with solar panels and
battery backup. There is the high voltage of up to 600 volts from the panels and the 120/240 volts in the building
AC Supply. When the main breaker is thrown to disconnect AC, the inverter will do as intended and maintain
voltage in the building. The 600 Volts from the panels, the 120/240 VAC and battery voltage are all still present.
Thus, throwing the mains did not remove any power at all.
The MidNite Solar Birdhouse, Disco Combiners and MNBDM Battery Disconnect Module work together to
remove power from the solar panels and disconnect DC from the batteries to the inverter removing all backup
power. All with the push of a single button.
690.12
Rapid Shutdown of PV Systems on Buildings.
PV system circuits installed on or in buildings shall include a rapid shutdown function that controls specific
conductors in accordance with
690.12
(A) through (D).
(A)
Requirements for controlled conductors apply only to PV system conductors of more than 1.5 meters (5
feet) in length inside a building, or more than 3 meters (10 feet) from a PV array.
(B)
Controlled conductors shall be limited to no more than 30 volts and 240VA within 10 seconds of rapid
shutdown initiation. Voltage and power shall be measured between any two conductors and between any
conductor and ground.
(C)
The rapid shutdown initiation methods shall be labeled in accordance with
690.56
(B).
(D)
Equipment that performs the rapid shutdown shall be listed and identified.
The following comment is one of many resulting from a consensus process established among three groups of
stakeholders: 1) CMP4 Firefighter Safety Task Group, 2) the SEIA Codes and Standards Working Group, and 3)
the PV Industry Forum.
9. ROP 4-325 (accepted) introduces a distance of 1.5m (5 feet) to disconnection means of indoor battery-backup
wiring. This distance is recognized as an acceptably short conduit length that allows for best practices in
workmanship, and can be applied to PV wires entering a building in addition to conductors in and out of
inverters and conductors coming out of a battery.
