A method of providing a secondary means of overload protection and leakage current protection in applications using solid state power controllers

A method of protecting an electrical power distribution system comprising:

• receiving a command to open or close a first switch, said first switch being connected between a source of electrical power and a load;
• determining if an over-current situation is present by determining if a current sense signal exceeds a predetermined threshold;
• and
• closing said first switch and opening a second switch when both the received command is a close command and the over-current situation is not present.

A leakage current protection circuit comprising:

• a solid state power controller connected to a source of electrical power and having an output, said solid state power controller having an ON state and an OFF state, wherein the electrical power is transferred to said output during said ON state and wherein a leakage current is transferred to ground potential during said OFF state;
• the ON and OFF state of the solid state power controller being determined by operation of a trip-engine controller that is responsive to over-current conditions in a feeder wire connected to the output:
• a switch connected between said solid state power controller output and said ground potential, said switch having an ON state and an OFF state;
• and
• the trip-engine controller coupled to said switch and causing said switch to be in said ON state whenever said solid state power controller is in said OFF state, wherein said leakage current from said solid state power controller passes through said switch to said ground potential.