US 8,605,402 B2 · Heat sensor responsive to electrical overloads

Abstract

Apparatus for detecting an overheating condition at an electrical power device and automatically breaking the circuit when the temperature exceeds a setpoint value. In various configurations the device is a receptacle adapted to be used in a wall mounted box or a receptacle unit that is plugged into an existing receptacle. A temperature sensor is wired parallel to a normally open test switch on a ground fault circuit interrupter or other circuit interrupting device. The temperature switch is responsive to the temperature local to the receptacle, such as is caused by poor connections to or in the receptacle or a near-overload condition. The temperature setpoint is less than the melting temperature of the insulation of the electrical wiring. The temperature sensor is a thermistor with a negative temperature coefficient that allows current to flow thereby latching the interrupting device in a tripped position until the device is reset for reuse.

Claims20

Dependent claims

An apparatus for detecting and interrupting an overheating condition, said apparatus comprising:

a module having a load side and a line side, said module including a circuit interrupter, said module selectively electrically connecting said load side to said line side, said load side electrically connected to a socket configured to receive an electrical power plug with at least two prongs;
a temperature sensor electrically connected to said module, said temperature sensor being a thermistor with a negative temperature coefficient, said temperature sensor responsive to a temperature proximate a load neutral conductor, said temperature sensor allowing a current to flow between said load neutral conductor and a ground conductor when said temperature is between a maximum operating temperature and an insulation melting temperature of a wire proximate said temperature sensor;
and said current being sufficient to trip said module and interrupt a circuit between said load side and said line side.

An apparatus for detecting an overheating condition at a power receptacle, said apparatus comprising:

a temperature sensor being a thermistor with a negative temperature coefficient;
a neutral lug electrically connected to said temperature sensor, said neutral lug having an end configured to mate with a neutral terminal in a receptacle;
a ground lug electrically connected to said temperature sensor, said ground lug having an end configured to mate with a ground terminal in said receptacle, said neutral lug and said ground lug each having a position configured to facilitate direct connection of said ground lug to said ground terminal and said neutral lug to said neutral terminal of said receptacle.

Dependencies are inferred from the claim text.

Heat sensor responsive to electrical overloads

Life of this patent

Heat sensor responsive to electrical overloads

Life of this patent

Abstract

Claims20