Protects your RV bumper to bumper from the most damaging common electrical faults. Unit will transfer to either shore power or generator automatically when energized. In the event both shore and generator powers are available, generator power will dominate after 30 second delay. Features open neutral, reversed polarity, 34 second delay for cold generator starts, 50 FLA rated contactors (full inductive load rated), mechanically interlocked contactors, electrical interlocked control circuit, black power-coated steel enclosure, rugged heavy-duty construction. Surge Rating Basic - firstname.lastname@example.org, Surge Rating Basic Plus Surge Board Option - 2600j @ 76.4KA60A full-rated contactor (75A resistive).