Ground potential OK?
As far as the ground potential goes I have a 4 wire set up in the house, and I also ran 4 wires out to the garage so I would think I would be OK there? There is a dedicated ground going from the ground buss in the house to the ground buss in the garage.
What I was worried about is the old cable I pulled out had the center wire protruding about 1/4 inch out of the end. The new wire I put in had that center wire recessed back in a compression connector. It screwed on to the splitter OK but I am not sure if that center wire is making contact inside since it was shorter?