Patent ID: 7902854

Claim:
An apparatus for mounting coupled with a power line carrying a high AC line voltage, the apparatus comprising: a conductive body having a body capacitance; a power supply comprising at least two input terminals; a first of said at least two input terminals coupled to said conductive body and a second of said at least two input terminals operative to be coupled to said power line; electronic circuitry coupled to said power line comprising: a voltage sensor operative to sense voltage on said power line, said voltage sensor having a metallic plate operative to form a first capacitance with an external reference; a second capacitance coupled between said metallic plate and a system reference; and detection circuitry operative to detect the voltage level on said metallic plate; wherein said power supply is operative to convert power flow between said conductive body and said power line into a supply of power at a voltage substantially lower than said high AC line voltage for operation of said electronic circuitry.