Abstract Electron-Beam Induced Resistance CHange (EBIRCH) is a technique that makes use of the electron beam of a scanning electron microscope for defect localization. The beam has an effect on the sample, and the resistance changes resulting from that effect are mapped in the system. This paper explores the beam-based nature of the technique and uses understanding from another beam-based technique, Optical Beam Induced Resistance CHange (OBIRCH), to propose a dominant mechanism. This mechanism may explain the widely different success rates between different types of samples observed after six month’s use of the technique for isolations on large health of line structures in a failure analysis lab.