I have 3 bundles of 3 12AWG THHN wires each,
- black-white-green (red tape)
- black-white-green (blue tape)
- black-white-green (black tape)
these 3 bundles come out of the load center and into 1/2 EMT. So 9 wires total, 6 of them current-carrying. (With 6 CCC's, I derated them 80% from 30A and put them on 20A/15A breakers)
At any rate, to avoid mixing up which neutral/ground goes with which hot, etc., at each junction box where two or more bundles exists, I have them bound together with colored electrical tape so as not to confuse myself or the person following behind me.
In the load center the bundles are marked with their color just as they go out into the conduit, then again at a junction box where they go their separate ways. Actually at any place where two or more bundles co-exist.
Is this going to trip out the person who follows me, or worse yet, be dangerously misleading?
Best Answer
It's mandatory
When putting identical-appearing circuits in a conduit, you must differentiate them somehow. It's mandatory.
I would not bundle them but mark them individually. Black(blue) and White(blue) for instance being the obvious pair. Bonus points: use a decent length (2") of shrinkwrap so the tape doesn't come off someday.
The reason I don't like bundling them is pulling. It will make pulling harder by making wires bind.
Get rid of those grounds
Grounds don't count against wire-size derate (on 10, 12, 14 AWG you are allowed 9 active conductors per conduit without worrying about derate). Having considered this math in every way possible on 120/240 split-phase, this means 4 circuits of any kind.
But they do count against conduit fill - in 1/2" EMT you are allowed 9 wires fullstop... and you are now full. Dump two of the grounds and you will be able to fit a fourth circuit. Use the 10-32 ground screws in the boxes to splice grounds.
EMT itself is a ground path. One ground in EMT is belt-and-suspenders. Three is inexperience. The only reason to pay the fill cost for that is if you were splitting the circuits into nonmetallic conduit downline, and the split point lacked any place to splice the grounds - I have had to do that.