Let me see if I understand my options. Let's forget about how the shared neutral is going to be tied in to hots on different poles, with a double pole breaker (or breakers tied together). I understand all that. Even though some don't judging by the comments here.
So basically, my options are
1. Expensive gfci breakers
2. Every outlet on a shared neutral circuit must be gfci and not just the first in line
3. Don't share neutrals. And only first outlet be a gfci and wire to standard breakers.
If that's correct, I'll probably just run the extra neutrals. All total there is going to be about 6 or 7 circuits and 30 or 40 recepticals. Not sure the exact count yet cause I don't know where all I may opt for doubles instead of singles.
I already have a ton of boxes, covers, and a 5 gallon bucket full of recepticals and switches. Also have a ton of breakers and rolls of wire. What I don't have is a ton of GFIs. I have maybe 6. So instead of buying another 30 GFIs or expensive breakers, I think it will be best to pull extra wire, since I have plenty, and use the receps and breakers I have already.
No no no. There has been a lot of bad info on this thread, with some very good info in between (from the resident electricians). If you use a GFi outlet in the first outlet position from the panel - AND wire it CORRECTLY - then you can protect the remaining outlets on that circuit as GFI also. The GFI outlet does not care that the neutral is shared - that issue is downstream of the outlet. It only cares what goes in and out of
that outlet (hot to neutral). Now when that neutral current joins up with out of phase neutral current from the other half of the circuit, they will partially cancel out, thus reducing the load on the neutral wire (which is why neutral derating is allowed), but that affects NOTHING in the outlet itself - what goes in comes out, or it trips. What it does downstream is irrelevant. With that said, some equipment just does not work well with GFIs. I have a router table with a magnetic switch that will not work on a gfi to save it's life. So I improvise to a non GFI circuit, for now.
If you want to share neutrals to save wire, here is how i see it:
1. run 3 wires plus ground from a common 2 pole breaker (basically a 220V breaker)
2. Connect one hot and the neutral to your first GFI
3. Connect your second hot and neutral to your second GFI
4. Wire in the remainder of those circuit chains from each GFI, using the correct terminals on the GFI and only one hot, one neutral, of course
Now one more point - you can put way more than 3 outlets on a circuit, even in a shop. Keep in mind these are mostly for convenience and will never be loaded to max. In a one man shop, there is only so much you will have running at once. If you isolate semi-dedicated loads like a compressor or dust collector, then everything else can easily run on only a couple 110V circuits. This is where you can save yourself some headache. I ran my shop in the old house off 2 20A circuits, and never tripped breaker. Now I have 5 circuits in the new shop, but only because the shop is bigger (like 5x). Still never tripped a breaker. I'm talking about 110 circuits here. I run separate 220V circuits as required as the bigger tools require some specific stuff, but I also ran a couple general 220v 20A circuits with multiple outlets, as that is common for a lot of stuff I have. How much can one man run at once?
You are using some common sense overall in asking, but put more outlets on one circuit, and for gods sake, don't try to pull 9x 12ga wires through a 1/2" EMT conduit. That is nutz. No matter what NEC conduit fill allows. My 2 Ohms.
