VIAIR “C” model compressors are intended to fill air tanks. They are not equipped with an ON/OFF switch or pressure sensitive shutoff device of any kind. The use of a pressure switch and relay are recommended and required. All “C” model VIAIR compressors (except certain 90 & 100 series units) are equipped with a stainless steel braided leader hose and a check valve to keep the compressor from restarting under pressure which can create an amp draw spike and can cause motor damage. Most VIAIR compressors are equipped with a thermal overload protector that will shut down the unit when overheated. When cool, the compressor will automatically restart as normal.