A photovoltaic (PV) module safety shutdown system includes a module-on switch coupled with a PV module coupled with an alternating current (AC) mains panel through an inverter. A system monitor couples with the module-on switch and with the AC mains panel and generates a system-on signal. A module discharge switch couples with an inherent capacitance of the inverter and with the system monitor. The module discharge switch discharges the inherent capacitance, by coupling the inherent capacitance with a discharge element, in response to the system monitor not generating the system-on signal. In implementations a module short switch shorts the PV module in response to a passage of a predetermined amount of time after the module discharge switch is switched on. The module-on switch, module discharge switch, and module short switch may be included in a junction box of the PV module and coupled with the system monitor through multiple opto-isolators.