The MidNite Little Shut-Off Box system is a simple rapid shutdown system that does not require any extra wiring between the grid tie inverter and the PV array. One receiver is used with each inverter to meet NEC 2014 and NEC 2017 code up to the end of 2018. One transmitter can be used with up to six strings. To meet the 2017 NEC code starting in 2019 one receiver is installed per module. The transmitter sends a keep-alive signal over the PV output circuit to tell the receivers to turn on. When the transmitter is disconnected from power, or by a separate shut off button, it turns off and the signal is interrupted and the receivers turn off. Safety is enhanced since any time the transmitter is not on, or should fail, the array will be shut down. Restoring power to the transmitter will turn the system back on. The MNLSOB-T1-600 transmitter is powered by a 250 mA 12 volt DC power supply.