Patent ID: 8395372

Claim:
A method of measuring current in a current carrying cable having a normal distribution level of current, the method comprising the steps of: providing an optical sensor assembly comprising: a base unit; and an optical current sensor mounted with respect to said base unit said optical current sensor capable of receiving a polarized light input, and capable of transmitting said polarized light therethrough in a reflective manner, and capable of exposing said transmitted reflected polarized light to a magnetic field and provide a rotated, polarized light output after exposure to said magnetic field, due to the Faraday effect, said rotated, polarized light output being representative of the current creating said magnetic field; providing a source of polarized light, said source connected to provide polarized light input to said optical current sensor; providing a magnetic concentrator, having a high current saturation level substantially above said normal current level in said cable, wherein said magnetic concentrator is adapted to be disposed in close proximity to said current carrying cable and create said magnetic field representing the current in said cable; providing an airgap across which said magnetic field extends; hanging the optical sensor assembly downwardly from the current carrying cable; providing means for placing said optical current sensor in said magnetic field within said airgap whereby is provided said output of rotated, polarized light; and providing light detector means for receiving said rotated polarized light and converting it to analog electrical signals representative of the current in said cable, without cutting said cable or otherwise disrupting any function of said cable.