Residential fault diagnostic tool

A method of performing diagnostics on a branch circuit with a plurality of electrical outlet locations in an electrical system, the branch circuit having a plurality of electrical conductors including a power line, neutral line and ground line, the method comprising:

• connecting a plurality of diagnostic devices to upstream and downstream electrical conductors of the branch circuit at different electrical outlet locations, each diagnostic device including:
• a load, a power supply, sensors for measuring electrical characteristics on the branch circuit to monitor current on the power, neutral and ground lines, and switching circuitry for isolating an upstream or downstream section of the branch circuit from the electrical outlet and for selectively connecting or disconnecting the power supply or the load to the section of the branch circuit upstream or downstream from the electrical outlet location, via the electrical connectors;
• controlling the switching circuitry of each of the plurality of diagnostic devices to provide different combinations of power supply and load connections along the branch circuit in order to isolate and monitor load currents on different sections of the branch circuit including sections between electrical outlet locations having diagnostic devices connected thereto;
• and
• determining a type and location of a fault on the branch circuit based on the monitored load currents, or a mapping of the outlet locations along the branch circuit based on the monitored load currents,
• wherein diagnostic operations are performed under control of a computer device, and the determining operation is performed by the computer device based on diagnostic information corresponding to monitored loads, which are received from the plurality of diagnostic devices.

A tangible computer memory device storing computer executable code, which when executed by a computer, implements a method of performing diagnostics on a branch circuit with a plurality of electrical outlet locations in an electrical system, the branch circuit having a plurality of electrical conductors including a power line, neutral line and ground line, a plurality of diagnostic devices being connected to upstream and downstream electrical conductors of the branch circuit at different electrical outlet locations, each diagnostic device including:

• a load, a power supply, sensors for measuring electrical characteristics on the branch circuit to monitor current on the power, neutral and ground lines, and switching circuitry for isolating an upstream or downstream section of the branch circuit from the electrical outlet and for selectively connecting or disconnecting the power supply or the load to the section of the branch circuit upstream or downstream from the electrical outlet location, via the electrical connectors, the method comprising:
• controlling the switching circuitry of each of the plurality of diagnostic devices to provide different combinations of power supply and load connections along the branch circuit in order to isolate and monitor load currents on different sections of the branch circuit including sections between electrical outlet locations having diagnostic devices connected thereto;
• and
• determining a type and location of a fault on the branch circuit based on the monitored load currents, or a mapping of the outlet locations along the branch circuit based on the monitored load currents,
• wherein diagnostic operations are performed under control of a computer device, and the determining operation is performed by the computer device based on diagnostic information corresponding to monitored loads, which are received from the plurality of diagnostic devices.

A diagnostic device for performing diagnostics on a branch circuit of an electrical system, the branch circuit having a plurality of electrical conductors including a power line, neutral line and ground line, the diagnostic device comprising:

• electrical connectors including a first set of terminals for connecting to the electrical conductors of the branch circuit in an upstream direction at an electrical outlet location, and a second set of terminals for connecting to the electrical conductors of the branch circuit in a downstream direction at the electrical outlet location;
• a load;
• a power supply;
• switching circuitry, which is coupled to the first and second sets of terminals of the electrical connectors, the load and the power supply, for isolating an upstream or downstream section of the branch circuit from the electrical outlet, and selectively connecting or disconnecting the power supply or the load to the section of the branch circuit upstream or downstream from the electrical outlet location, via the electrical connectors;
• and
• sensors for measuring electrical characteristics of the electrical conductors on the branch circuit to monitor current on the power, neutral and ground lines;
• and
• at least one processor configured:
• to control the switching circuitry to selectively connect either the power supply or the load to the portion of the branch circuit either upstream or downstream from the electrical outlet location;
• and to obtain diagnostic information corresponding to the monitored current on the power, neutral and ground lines based on the measurements performed by the sensors,
• wherein the power supply is a variable power supply, and wherein the at least one processor is further configured to control an amount of power supplied by the variable power supply to the isolated section of the branch circuit either upstream or downstream from the electrical outlet location.

A diagnostic device for performing diagnostics on a branch circuit of an electrical system, the branch circuit having a plurality of electrical conductors including a power line, neutral line and ground line, the diagnostic device comprising:

• electrical connectors including a first set of terminals for connecting to the electrical conductors of the branch circuit in an upstream direction at an electrical outlet location, and a second set of terminals for connecting to the electrical conductors of the branch circuit in a downstream direction at the electrical outlet location;
• a load;
• a power supply;
• switching circuitry, which is coupled to the first and second sets of terminals of the electrical connectors, the load and the power supply, for isolating an upstream or downstream section of the branch circuit from the electrical outlet, and selectively connecting or disconnecting the power supply or the load to the section of the branch circuit upstream or downstream from the electrical outlet location, via the electrical connectors;
• and
• sensors for measuring electrical characteristics of the electrical conductors on the branch circuit to monitor current on the power, neutral and ground lines;
• and at least one processor configured:
• to control the switching circuitry to selectively connect either the power supply or the load to the portion of the branch circuit either upstream or downstream from the electrical outlet location;
• and to obtain diagnostic information corresponding to the monitored current on the power, neutral and ground lines based on the measurements performed by the sensors,
• wherein a level of voltage supplied by the power supply and/or a level of load connectable to the branch circuit is selectively controllable to limit current on the branch circuit to a current level which can prevent or reduce a potential hazardous arc fault from reaching a hazardous level.