In 2014 NEC 690.12(2), Eventhough the controlled conductors are not more than 10 ft which are located outside the building, Do I still need to install "rapid shutdown" the controlled conductors are more than 30 volts and 240 volt-ampere?
Confining our discussion to the 14 Code, inverter control of the array needs to be compliant with 690.12 regardless of the length of the conductors. The situation is that the conductors leaving the roof need to be constrained to the voltage and wattage cited. String inverters with out some means of rooftop control (optimizers/contactors) will still be energized with the inverter off. The intent was to have the control at the source, not some random location somewhere on the rooftop.
The intent of 690.12 is to bring the voltage down from the ~300 - 500Vdc levels at production to zero or near zero.
The placement of the controlling means within 10' of the array was intended to emphasize the need for some delineation for first responders to attempt to identify where the conductor control might be. The sad thing is that they're not really going to know and aren't going to spend the time figuring out what type of inverters are on the house. A string inverter with no contactor or module level electronics and a microinverter system look exactly the same on the rooftop. The firefighters aren't going to remember that there wasn't a central inverter as they step off the ladder. This has led to questions regarding efficacy of the article.
The guiding principle behind 690.12 was supposed to be first responder safety. There is some difference of opinion as to whether it really got addressed. The 2017 Code tried to enhance this to make it more clear but also more restrictive. In my opinion, the 17 language missed the mark slightly due to the parsing of the various boundaries down to the 1 foot distance. 690.56(C)(1)(a) and (b) define how the system shall be labeled. The red and yellow label conditions are left open for interpretation because when you install SolarEdge inverters with the optimizers on the modules, the shutdown event does restrict the system voltage to ~1V per module. However, the language of (b) causes one to stop and ask, did they mean shut down as in reduce voltage, or shut down as in zero volts?
My interpretation is that the system shutdown event occurs and as per the "shutdown" the SolarEdge array conductors have been controlled. A string inverter with a rooftop contactor will always have full voltage leaving the array to the 1 ft. boundary.
I hope this helps.
NABCEP Certified Installation Professional
Retrieving data ...