Over-voltage protection

Circuit protection apparatus for disconnecting a power distribution circuit having a plurality of energized lines and a neutral line coupled between an A.C. energy source and a utilization device, said apparatus comprising:

• Circuit interruption means having a pole in electrical series connection with each said energized line;
• trip means coupled to said circuit interrupting means for substantially simultaneously disconnecting all energized lines from said utilization device responsive to an energization of said trip means;
• a spark gap device having an input and an output, said output being coupled to said trip means;
• a plurality of semiconductor diodes, each said diode having an anode and a cathode, each of said diode anodes coupled to a different one of said energized lines, each of said diode cathodes coupled together to form a common junction therebetween, said common junction being coupled to said spark gap device input;
• said spark gap device having a gap distance selected to cause said spark gap to fire responsive to a peak voltage at said spark gap device input in excess of a predetermined value such that said spark gap device couples a substantially zero amount of energy to said trip means when the voltages on all said energized lines are less than said predetermined value and said spark gap device energizes said trip means when the voltage on any one of said energized lines exceeds said predetermined value.

Circuit protection apparatus for disconnecting a power distribution circuit having a plurality of energized lines and a neutral line coupled between an A.C. energy source and a utilization device, said apparatus comprising:

• circuit interruption means having a pole in electrical series connection with each said energized line;
• trip means coupled to said circuit interruption means for substantially simultaneously disconnecting all said energized lines from said utilization device responsive to an energization of said trip means;
• a diac having an input and an output, said diac output being coupled to said trip means;
• a plurality of semiconductor diodes, each said diode having an anode and a cathode, each of said diode anodes coupled to a different one of said energized lines, each of said diode cathodes coupled together to form a common junction therebetween, said common junction being coupled to said diac input;
• said diac having a threshold voltage selected to cause diac to conduct responsive to a peak voltage at said diac input in excess of a predetermined value such that said diac couples a substantially zero amount of energy to said trip means when the voltages on all said energized lines are less than said predetermined value and said diac completes a conductive path between said junction and said trip means so as to energize said trip means when the voltage on any one of said energized lines exceeds said predetermined value.