I have a detached garage built in 1979 with a Cutler Hammer subpanel with a 3-wire 8AWG feeder (hot/hot/neutral) on 40A breaker from the main house panel. Subpanel has a dedicated ground rod installed.
The neutral is tied to the ground. Shouldn't this be separate for a subpanel?
I think I need to install a second block to isolate the feeder neutral and building neutral. Does that sound right?