This IEEE Standards product is part of the C37 family on Switchgear, Substations and Protective Relays. This guide is intended to aid those engineers who have reevaluated the risks associated with faults within network vaults, particularly for those network vaults located within or near highrise buildings. It will also identify currently available devices that are being used in network transformer protection schemes. These devices should act to sense the fault and initiate fault interruption locally or remotely, thereeby minimizing damage and restoration time. These devices will be described as to their fault detecting capabilities. An example utilizing a number of protective schemes is presented in Appendix B.