Am doing some wiring with the standard blue plastic boxes and 12/2 wire. A ceiling box is 18 cu in and the stamp on it says 8/12. Do you count the bare copper wire as a conductor?
There will be one cable going in, one cable going to the next box, and one cable going to the switch. That's 9 total wires (too many?), or 6 if you don't count the bare wire as a conductor. I've got a chart that tells how to count clamps and pigtails.

 

All the grounds are taken together and count as one wire total.


3 hots
3 neutrals
1 ground
1 clamp

Total of 8 12 AWG wires. It just passes from this point of view. Some inspectors will allow you to not count the integral clamp in plastic boxes, but most require it to be counted. The clamps inside metal boxes always count.

Presumably there is a lamp (luminaire) hanging off this box. It has wires too, which may or may not need to be counted. If the lamp has a "domed canopy" and the fixture wires are less than 14 AWG, then they do not have to be counted. If the lamp does not have a domed canopy, then the box is over-full.

I have found a couple of practices, over the years, help avoid this problem for household wiring.

1) Keep lighting and receptacle circuits separate from each other.
2) Run your lighting circuits on 15 amp circuits with 14 AWG wire. They are rarely heavily loaded and do not need the heavier wire. The smaller wire is easier to work with and has much less tendency to run into box fill problems.
3) Run power from the panel to the switch, then from there to the lamp. This ensures neutral is available at the switch for future timers or dimmers or whatever, and it avoids box fill problems in the ceiling boxes.

 

I'll go get some 14/2 wire for the lighting circut. We've got a big spool of 12/2 here and I wanted to use that because I hadn't realized how much wire ad gone up in the last year or so. WOW! $$$ The 12 gauge will keep for later. Thanks.

 

I like to have unswitched power at the lighting fixture so I can mount a ceiling fan later if needed. The dimmers I have used just required a return path thru the cold bulb filament for power to the electronics. Motorized timers would of course require a neutral. Wind-up type timers do not require a neutral.

 

Most inspectors don't want a live wire in the ceiling box. They want to have the power off when the switch is off. The price of copper is really going up ($80) I still have a $31 roll which I think I'll have framed. Bronzing is too expensive.

 

Hot wires must not be a problem for the inspectors locally. About 50% of the houses around have the hot wire in the ceiling box. In my neighborhood it is 100%.

 

It depends on the municipalilty and often, the particular inspector. The NEC 2005 specifications (electrical contractor's bible essentially) doesn't have an opinion on this one way or another.

Most modern ceiling fans require two inputs - one for the light, another for the fan, and generally speaking it's more than acceptable to wire a potential ceiling fan by using 14/3 instead of 14/2, and not connect the third connector in the ceiling box or the wall switch box, until you're ready to use it. This way the wire is there, but not "live" until you slap a switch in the wall box.

Our house was built in 1941, and most of the wiring is jacketed romex, 14/2 with the jacket being ground. Unfortunately, the prior owners who were electrical idiots, replaced many of the switch and outlet boxes with blue plastic ones, which leaves the boxes ungrounded. I've replaced most of them (as I find them) with metal boxes to restore the ground, as I replace the 2 prong outlets with more useful 3 prong outlets.

I owned an electrical contracting business in the late 80's, and I have to tell you that inspectors from even the same municipality are often not consistant among themselves. I'd go out of my way to try and get the same inspector out for the second review as was there the first - to avoid having yet another opinion of how things should be and having to do the work yet again.

Same for fire inspections for commercial facilities.