I finally started digging into the 2014 changes. I expect this will be the first thread I will draw attention to various changes, and comment accordingly. I truly hope this leads to some lively discussion, and maybe even improves t NEC the next time around.
We are now required to identify neutrals with their associated 'hot' wires. This can be by marking, grouping, or obvious association (like them all coming out of tame pipe).
This section also adds a NEW prohibition against a single wire serving s the neutral for more than one circuit. (re on this in my next post).
"We need to start identifying our neutrals!" That was a comment made here by myself, long ago. It sure has it's advantages- and can easily become essential when there are AFCI's, GFCI's, and harmonics involved. But .... should it be code?
I was a lot more worried about it before I got involved with UPS-protected data circuits. For those jobs, keeping the neutrals rate was pretty important. When time came to pull wire though, it proved to be an exaggerated fear. Come connection time, it was virtually impossible to screw things up - unless you decided to put ALL the white wires under one wire nut.
The only time this as an issue was on a lighting circuit, where 5 separate circuits got mingled in one box, and only 2 neutrals made it home to the panel. I'll discuss that in the next post.
As for AFCI's, etc ... well, aren't we using Romex for those? Since the wires are all 'grouped' in the same cable, no other marking is required.
Now, I would LOVE to see a termination adjacent to the breaker for the neutral. That would encourage a natural 'grouping.' There is nothing in 200.4 to st such a design change by the panel makers.
I think this requirement is a bad one. At best, the sparky is forced to compensate for poor panel design- which forces all the neutrals to become a tangled mess in one corner of the panel.
The second new requirement in 200.4(B) is that you cannot combine neutrals from different circuits.
I one had the honor of paying for the $600 worth of damage caused when I failed to properly connect all the neutrals under a nut, and one worked loose. In that instance, the original installer had run out of room in the pipe back to the panel for all the wires- and the one that came loose resulted in 200+ volts on a 120v circuit. Oops. I have not liked putting 8 wires under the same big wire nut ever since!
Seriously, though .... this change forbids my solution to a similar pipe-fill issue. I had a house re-wire, where I was able to run only 1-1/4" pipe from the panel into the attic, where all the new circuits terminated. My solution was to place a gutter in the attic, and run all the circuits to the gutter. Inside the gutter I mounted a neutral bar and a ground bar. Thus, to the panel I only had to run one (larger) neutral and one (larger) ground. Each 'hot' continued to the panel.
I think it's foolish to try to reduce the trade to only "simple" solutions. There's a place for the professional to actually design things; we're reduced to 'cookbook' approach.
I suspect all these 'problems' are only being discovered now, because -after a century of electrical work- we're seeing a new class of inspectors, plan reviewers, managers, etc. who have only 'book' learning, and have not mastered any trade. We're being governed by the ignorant.
I never thought it was legal to combine neutrals. I assumed it happened occasionally in those octopus ceiling boxes and gang boxes with 5 switches in them but I thought AFCIs stopped that stuff.
I do think grouping neutrals in multiwire circuits, along with the other ungrounded conductors is a good idea. A tywrap does that.
I guess a related question is how do you identify the neutrals if you have a few ungrounded conductors with 2 or more circuits? Is it legal to put a wrap of colored tape on the white wire to identify it as going with a like colored ungrounded conductor?
The deal is, because of the electronics and their embedded algorithms for detecting circuit faults, residential circuits are going all the way over to dedicated neutrals.
As this progresses, I expect to find the NEMA players to have crafted use specific circuit breakers for yet other circuits.
A lot of this is actually coming by way of the US Navy. They've had a DARPA program -- now getting on in years -- to entirely recraft the circuit protection logic of naval circuits. The Navy wants to move entirely away from 'dumb' circuit protection. Smart protection is to be built in -- up and down the line.
Eventually, the hope is that an internal smart grid will give combatant ships almost 'Star Trekian' diagnostic routines. This is but another way that Star Trek has lept from the silver screen into 3-D space.