If a feeder to a separate building is installed in rigid metal conduit, can the conduit serve as the required equipment grounding conductor?

The question addresses whether a rigid metal conduit can serve as the required equipment grounding conductor for a feeder to a separate building. The correct answer indicates that this is not permissible.

A rigid metal conduit (RMC) can indeed provide some grounding benefits because it is made of conductive metal. However, for a feeder to a separate building, the National Electrical Code (NEC) specifies that an independent equipment grounding conductor must be installed alongside the feeder conductors. This requirement exists to ensure that there is a dedicated path for fault current, which is vital for the safety and proper operation of electrical systems.

Using the conduit alone as the grounding conductor may not provide enough grounding reliability due to potential interruptions or discontinuities in the grounding path. Moreover, keeping the grounding and bonding systems separate between buildings helps maintain the safety of both systems. In summary, while RMC is a good conductor, it does not meet the specific grounding requirements when it comes to feeders supplying distant buildings.