Patent attributes
A semiautomatic switching device is configured to selectively connect one of two power sources to a load. Each of the power sources is a split-phase power source including a first hot lead, a second hot lead, and a neutral lead. When the second split-phase power source is generating power, the voltage between the first or second hot lead and the neutral lead closes a corresponding first or second contact. The first and second contacts are connected in series between the first hot lead, the second hot lead and a third switch. The voltage potential present between the first hot lead and the second hot lead closes a third and fourth contact. The third contact is connected in series between the first hot lead and the load and the fourth contact is connected in series between the second hot lead and the load. The switching device protects against open neutral conditions.