So I have a situation where I need to use a direct burial 10/2 with Ground to feed Two 120vac branch circuits by using the ground wire as a shared neutral.
Worse yet, the 10/2 cable has no neutral wire but does have a ground wire. This Direct burial 10/2 is installed in 3/4" PVC Sch 40 conduit. All of this is fed via a 30amp double pole breaker (L1 and L2).
Ground and neutral bus bars are connected together in this panel so effectively Ground and Neutral are one and the same leaving this panel.
So, can I take for example take one hot wire (Black wire (L1)) using the ground wire in the same cable having it act as a shared neutral, knowing it's a ground wire typically? I read the GFCI will work without Ground, yes no Ground.. keep reading...
So it would be a 120vac circuit Using L1 and Ground/Neutral. KNOWING I have no ground (a recipe for disaster), can I then run a ground rod and ground all the outlets back to the earth ground where this branch circuit will be located? All the outlets are plastic NEMA boxes with GFCI outlets installed 15amp.
The panel box is 150' from where the GFCI circuits are located so yes there is a potential for a small difference in potential from the ground rod to the panel box.
I understand there are two ways to wire multiple 20A 120V circuits. You can wire each one separately, in which case they use separate neutrals (e.g., 12/2 to each string of receptacles) or they can share the neutral. If they share the neutral, that is a Multiwire Branch Circuit or MWBC. An MWBC shares neutral, which saves the cost of one wire, and can do that because the current on the neutral from each leg cancels the other one out.
I think the Jury is in... the overwhelming majority so NO GO !!
I happen to have an Isolation Transformer by Victron Energy https://www.victronenergy.com/upload/documents/Datasheet-Isolation-Transformers-EN.pdf 2000watt, will this work? The theory would be to feed this with the 240vac 10/2 and just feed one 120vac circuit off of it. This appears to give me a true neutral and point for PE ground.