Parallax Power Supply&nbsp; (ALS20 Automatic Load Shed Device 6 Inch Width x 4-1/8 Inch Height x 4-7/16 Inch Depth The Automatic Load Shed Device (ALS 20) allows operation of two 20Amp loads from a single 20 Amp branch circuit Meets NEC requirements for operation of two 120-volt thermostatically controlled devices ALS 20 operates a shedable load such as an electric water heater and a priority load such as a microwave oven ALS 20 is an important safety and performance enhancement for RV electrical systems