A lighting driver (600, 800, 900) receives an AC Mains voltage (15), employs a rectifier (630, 830, 930) to produce a rectified voltage, and supplies an output current (665) to a lighting device (20) in response to the rectified voltage. A surge protection circuit (840, 940) of the lighting driver includes a voltage clamping device (MOV2) connected across the output of the rectifier, and a differentiator circuit (843/845/847/849, 943/945/947/949) configured to differentiate between a temporary voltage spike at the input to the rectifier and a loss of neutral connection to the lighting driver. When a temporary voltage spike is detected, the voltage clamping device is activated to clamp the rectified voltage until the temporary voltage spike ends. When a loss of neutral is detected, the voltage clamping device is latched into a disabled state until the AC Mains voltage input to the lighting driver is turned off.

Safety device for an electrical apparatus powered by an AC mains power supply, the safety device comprising: an electric circuit having inputs for connecting to an active, neutral and earth conductors of the electrical apparatus which are in turn coupled to the AC mains power supply, the circuit being operable to: produce and apply a stepped down voltage and current to the earth conductor from the main supply; and electrically isolate the active and neutral conductors from the earth conductor in response to detecting that either: the active conductor is incorrectly wired to the neutral circuit of the AC mains power supply; the neutral conductor is incorrectly wired to the active circuit of the AC mains power supply; or the neutral conductor is switched; wherein one or more solid state relays are employed by the circuit for both producing the stepped down voltage and electrically isolating the conductors from earth.

In a control device, control circuit units are connected to separate circuit power sources and to separate grounds. Ground monitor circuits respectively have a first resistor with one end connected to a voltage source, a second resistor with one end connected to an input terminal of a corresponding control circuit unit, and a capacitor. Among the one end of the first resistor, an other end of the first resistor, and the other end of the second resistor, at least one is connected to the subject system, and at least one is connected to an other system, and the control circuit unit monitors a ground abnormality of the other system based on a terminal voltage of the input terminal to which the second resistor is connected.

A test signal is applied from a continuity test source to a photovoltaic (PV) panel string, to test electrical continuity in the PV panel string and between the PV panel string and an inverter that is coupled to the PV panel string. If the test signal is detected at a PV panel disconnect switch that is separate from the continuity test source and switchably couples one or more Direct Current (DC) PV panels in the PV panel string, then the PV panel disconnect switch is controlled to connect the one or more DC PV panels in the PV panel string. Otherwise, the PV panel disconnect switch is controlled to disconnect the one or more DC PV panels from the PV panel string. The test signal could be, for example, an Alternating Current (AC) signal tuned to a PV installation that includes the PV panel string and the inverter.

A Protective Earth (PE) loss detection method for charging an electrical vehicle is provided. The electrical vehicle comprises an Electrical Vehicle Supply Equipment (EVSE), a charging connector, and/or a charging cable comprising at least a Proximity Pilot (PP) line for a PP signal, a Control Pilot (CP) line for a CP signal and a PE line for a PE signal. The method comprises detecting interruption of the PE line by observing a change of the PP signal.

A protection circuit provides a control voltage to a 3-phase contactor, where the three phases of the 3-phase power supply are inputs to the 3-phase contactor. The protection circuit includes: four input terminals, configured to be connected respectively to the three phases and to the neutral line of the 3-phase power supply; an output terminal, providing the control voltage to a control line of the 3-phase contactor; and control circuitry configured to provide the control voltage when any one or more of the three phases are live and when the neutral line is connected, and to provide no control voltage when all three phases are disconnected or when the neutral line is disconnected.

An apparatus for phase operation indication includes a phase filter that filters a ground monitor signal from one or more phase conductors supplying power to a load and injects the ground monitor signal in an equipment grounding conductor run with the one or more phase conductors or receives the ground monitor signal from a signal generator and injects the ground monitor signal on the one or more phase conductors. The ground monitor signal includes a test frequency different than a line frequency of power supplied to the load. The apparatus includes at least one indicator circuit connected to at least one of the one or more phase conductors. An indicator circuit of a phase conductor provides a visual flashing signal in response to a voltage being present on the phase conductor, the at least one indicator circuit located at the phase filter.

A lighting driver (600, 800, 900) receives an AC Mains voltage (15), employs a rectifier (630, 830, 930) to produce a rectified voltage, and supplies an output current (665) to a lighting device (20) in response to the rectified voltage. A surge protection circuit (840, 940) of the lighting driver includes a voltage clamping device (MOV2) connected across the output of the rectifier, and a differentiator circuit (843/845/847/849, 943/945/947/949) configured to differentiate between a temporary voltage spike at the input to the rectifier and a loss of neutral connection to the lighting driver. When a temporary voltage spike is detected, the voltage clamping device is activated to clamp the rectified voltage until the temporary voltage spike ends. When a loss of neutral is detected, the voltage clamping device is latched into a disabled state until the AC Mains voltage input to the lighting driver is turned off.

The RC-LED Snubber Capacitive Voltage Nullification Circuit can aid in preventing the influence of capacitive voltages, particularly when applied with metering applications in the course of determining the wiring polarity. The use of this circuit can prevent false Correct Wiring conditions and will enhance reliability for other meters that rely on proper wiring for accurate results.

Methods and apparatus for adaptive surge protection are disclosed. An example method comprises providing load voltage to the electric load by regulating a source voltage with a surge protection device; monitoring, via a voltage detection circuit, the source voltage from an electric source, and determining, via a wiring diagnostic circuit, whether a wiring fault is detected; monitoring, via a lightning detection circuit, for the presence of lightning within a threshold distance of the surge protection device; and breaking, with a switching device, a circuit connection to stop providing the load voltage to the electric load in response to detecting at least one of: a presence of the wiring fault, the presence of lightning within the threshold distance, an overvoltage at the source voltage; or an undervoltage at the electric source.