Abstract: A wire sensing and measurement apparatus comprises an optical fiber having a hook shape formed at one end and connected to an optical pulse generator at the opposite end for transmitting a continuous stream of optical pulses to the free end of the hook. An optical detector is positioned opposite the free end of the hook to detect pulses emitted from the hook, and is connected to a missing pulse monitor for monitoriing the output of the detector to detect any missing pulses in the sequence. The monitor produces an output pulse for each missing pulse detected. The hook is moved beneath expected wire positions and any wire passing between the free end of the hook and the detector will interrupt the stream of pulses, allowing the wire position to be located. The fiber optic hook may be used as part of a wire pull test machine for testing the strength of electrical circuit wires.