purgastries de 120-volt 30-amp 50-amp protects protects surge suppression electrical rating 30-amp 50-amp surge failure indication miswired pedestal protects protects indication shutdown open neutral shutdown shutdown reverse polarity shutdown shutdown open ground shutdown shutdown protection ac frequency shutdown time delay at power up members sale reg indication indication indication indication indication indication dc power for rv electronics and appliances best seller! three-stage battery charging maintains battery life with three nominal voltage output automatic 3-stage charging extends battery life assembly replaces the lower power converter section on your built-in converter step up to better dc power for lights and appliances