I recently was doing a sub panel fed from another sub.Now it had ser but they cut the neutral and just ran a bare ser/seu conducter from the ground bar to the neutral bar.So I did it the way it should be neutral to neu bar and bare grn to grn bar.But they had no continuity so I went to the panel feeding my panel and the neutral from the ser was cut and not terminated.So I went back to my panel and screwed in the bonding screw so the neu and the grn bar would be bonded and the circiuts would work.Well They didn't and the bond wasn't made after screwing in the bond screw .My boss came out and made me cut the neu and take the bare grn wire and terminate it to the neu bar then everything worked.Why didn't it work after bonding the neu bar to the panel where the grn bar is bonded to the panel enclosure.