On a recent Inspection, I came across a New Garage that had the power supplied by an Existing underground Feeder to a Sub-Panel. The panel was feed with 3 Wires Black,Red,White. NO Green. (Existing installation) The Sub Panel had a Separate grounding bar with a grounding electrode conductor running outside to 2 newly installed ground rods, The Neutrals and grounds were separated in the panel. I Have passed this information around to my local resources and all agree this is an acceptable installation???? I disagree. As this installation is missing one crucial component. An EGC back to the main panel. This installation is using the ground rods to clear a fault. Which a 120 volt line to case fault will not trip a 15 amp breaker unless the resistance of the ground rods is very low. Code requires a minimum of 25 ohms or an additional electrode. How can a New Garage be supplied by an existing Feeder and be compliant without an EGC? I appreciate any input in this discussion.