I am in Michigan if that makes a difference to you.
I am wiring a subpanel (QO 100-Amp Rainproof Main Lug Load Center) to my detached barn. I am feeding the subpanel from a 30A double breaker in my house's main panel. The feeder is 10/3 with ground, buried in conduit, 2 conductors, 1 neutral, 1 ground, supplying 240V at the subpanel.
In order to make working in the subpanel more safe, I have elected to install a 30A fused safety switch (GE TG3221) inline before the subpanel inside my barn, feeding the subpanel from the safety switch. All the wires will be the same 10/3 w ground.
Inside the safety switch box, there is a 3-lug isolated neutral bar, with an optional green screw to bond that neutral bar to the box. There is no equipment grounding bar in the safety switch box.
Now, I am well read on the fact that the neutral and ground in the subpanel MUST be ISOLATED. but in the safety switch box, I'm not sure. Since I'm feeding from my main panel (where the neutral and ground are bonded) I'm thinking that they should stay bonded inside the safety switch and only get isolated in the subpanel.
I have driven an 8' grounding rod, which I plan to connect (with #8 bare Cu) to the ground inside the subpanel, which will, once again, be isolated from neutral inside the subpanel.
Can anyone advise me on the question of whether or not the ground and neutral should stay bonded inside the safety switch? I am thinking that the options are:
Bond ground and neutral simply by using the neutral bar lugs to connect all the neutrals and grounds (not sure if using the bonding screw would be needed here)
Bond ground and neutral by connecting neutrals to neutral bar, installing bonding screw. Next installing an equipment grounding bar (to the box) and connecting the grounds to that (bonded) ground bar.
Isolate by connecting the neutrals to the neutral bar (NO BONDING SCREW). Installing an equipment grounding bar (to the box) and connecting the grounds to that bar (which will be isolated from the neutral bar w/o the bonding screw).
I've tried to include all the relevant details, but let me know if I missed anything.