Abstract: The scope of the guide includes the grounding practices presently used and the practices that were not previously reported. Specifically@ the issue of the grounding of cases of electronic transducers is addressed.The scope of the guide includes the grounding practices presently used and the practices that were not previously reported. Specifically@ the issue of the grounding of cases of electronic transducers is addressed.Purpose This guide provides information on the grounding of the following: - Secondary circuits of electromagnetic CT and VT circuits - Cases of relays@ CTs@ and VTs - Secondary circuits of optoelectronic CTs and VTs The primary emphases of this guide are personnel safety and proper performance of relays at electric power frequencies.?