I have a 125A GE PowerMark Gold Load Center "subpanel" at my detached garage. Subpanel has 2 hots, one neutral with no "connected" ground between panels. The subpanel ground bus bar is tied to a local 8ft subterranean 5/8" grounding rod. 50A branch breaker at main feeding 6/3 wire about 100ft tied directly to the subpanel inlets (H/H/N). Per NEC, the neutral and ground in the subpanel are not bonded (i did not screw in the green bonding screw that came with the panel).
All the outlets including GFCIs all work correctly. When I test panel buses with my meter in the garage I have 120v between neutral and each hot and have 120v between ground and each hot. Sounds good right? Then why do I have continuity between neutral bus bar and ground bar also between neutral bus bar and panel box itself?!? I thought that if I don’t insert the screw, then neutral should be "separate" from ground and panel metal box? Or is this normal?