A customer has a sub-panel on an the inside of an exterior wall of a barn type building. I need to remove this panel and install a new panel on the other side of the wall (outside of the building). I guess that doesn't really matter to you.
Here's my situation. There is a meter/main combo on the side of the house which feeds a sub-panel located in the house. The main panel also fed a 240V branch circuit going to a disconnect located at the back of the house. Somebody before me removed the interior of the disconnect and used it as a junction box to feed the same sub-panel I am trying to relocate. Here's the problem, there is no equipment ground between the main and sub-panel. There are only two 120V legs and a Neutral between the two panels. For ground at the sub-panel, there is a grounding electrode. I am trying to squeeze under 2002 NEC 250.32(B)(2) and bond the neutral bar to the sub-panel can. It would be easy to pull an equipment ground between the junction box and the sub-panel, however it won't be so easy to get a ground between the junction box and the main panel (both are on exterior walls of the house). I qualify under parts 1 & 2 of the Article, but part 3 seems to catch me. Where...ground-fault protection of equipment has not been installed on the common ac service. Since this is a residential installation, there is obviously ground-fault protection located somewhere in the house. However, it is not coming from the main panel, only the sub-panel located in the house. Does this still fall under the "common ac service"? Besides this, the junction box (old disconnect), contains splices of the current carrying conductors feeding the barn sub-panel.
What can I legally get away with?