Distributed arc fault protection between outlet and circuit breaker

An arc fault detection device for detecting an arc fault condition according to conditions monitored at multiple locations on a branch circuit, comprising:

• an upstream sensor for measuring a branch origin voltage or current at a branch origin upstream of the plurality of end-use devices on the branch circuit;
• a communications interface;
• and
• a controller configured to:
• receive information corresponding to the branch origin voltage or current measurement sensed by the sensor;
• receive, via the communication interface, information corresponding to a downstream voltage or current measurement at each of the end-use devices sensed by a corresponding downstream sensor;
• compare the branch origin voltage or current measurement to the downstream voltage or current measurements at the end-use devices;
• detect an arc fault condition based on the comparison;
• and
• issue a trip signal to trip a circuit breaker that defines the branch if an arc fault condition is detected.

A distributed arc fault detection system comprising:

• a plurality of end-use devices on the branch circuit, each end-use device including:
• a downstream sensor for measuring a voltage or current at the end-use device;
• a communications interface;
• and
• a controller configured to control transmission of voltage or current measurements via the communication interface to an arc fault detection device;
• and
• the arc fault detection system including:
• an upstream sensor for measuring a branch origin voltage or current at a branch origin upstream of the plurality of end-use devices on the branch circuit;
• an upstream communications interface;
• and
• an upstream controller configured to:
• receive information corresponding to the branch origin voltage or current measurement sensed by the upstream sensor;
• receive information from each end-use device corresponding to a downstream voltage or current measurement at the end-use devices;
• compare the branch origin voltage or current measurement to the downstream voltage or current measurements at the end-use devices;
• detect an arc fault condition based on the comparison;
• and
• issue a trip signal to trip a circuit breaker defining the branch if an arc fault condition is detected.