Introduction: This is a staged project to develop a non-invasive fault passage indicator for retrofit locations on the HV cable network.

Stage 1 of the project confirmed the theory that surface mounted magnetic sensors should be able to detect both overcurrent and earth faults on cable networks.

Stage 2 undertaken this year, was to determine the availability of suitable magnetic sensors with the sensitivity and linearity to work effectively in a practical FFI.

Objectives: This project is intended to develop a practical and reliable, while novel in design, fault passage indicator for HV cable networks. Though mainly intended for retrofit applications, it could be used effectively in new locations as well.