2014, 200.4 (B)

[sparky=t]

I believe the intent is to group the grounded conductors of a MWBC when in a gutter, wire way, junction box ect, how ever if you went to article 100 and looked up enclosure it may not apply to switch boxes or 4 squares.

2014 NEC Change
New 200.4(B), Multiple Circuits, requires grouping the common neutral
conductor for multiple circuits with their associated ungrounded conductors
when contained in the same enclosure. New exceptions were also added
to relax this grouping requirement where the grouping is obvious or where
looped conductors or conductors simply pass through the enclosure.

:?

 

[sparky=t]

any other interpetations / opinions?

 

[don_resqcapt19]

It appears that the CMP fell into the trap of using "common" language and not "code" language.

I agree that enclosure does not include device or outlet boxes.

 

[Smart $]

It appears that the CMP fell into the trap of using "common" language and not "code" language.

I agree that enclosure does not include device or outlet boxes.

Agree with "common" language. However, I will say Exception No. 2 infers this requirement also applies to boxes. But only branch circuits?

Also note the requirement starts with neutral conductor, then stipulates the grounded circuit conductors is what the requirement applies to. In most cases the neutral is the grounded conductor, but what about when the grounded conductor is not a neutral (or vice versa)?

And just to nitpick, Exception No. 1 uses the if rather than where.

Perhaps should be something like...

(B) Multiple Circuits. Where multiple-circuit conductors are accessible and otherwise not distinguishable by characteristic, such as but not limited to size or entry, the conductors shall be identified or grouped to make the conductors of each circuit obvious.

If you like this verbiage, feel free to propose it for next cycle.

 

[infinity]

There is also a code change (underlined) written by one of our mods in 210.4 that would apply specifically to panelboards.

210.4(D) Grouping. The ungrounded and grounded circuit con-
ductors of each multiwire branch circuit shall be grouped
by cable ties or similar means in at least one location within
the panelboard or other point of origination.
Exception: The requirement for grouping shall not apply if
the circuit enters from a cable or raceway unique to the
circuit that makes the grouping obvious or if the conductors
are identified at their terminations with numbered wire
markers corresponding to the appropriate circuit number.

 

[don_resqcapt19]

Agree with "common" language. However, I will say Exception No. 2 infers this requirement also applies to boxes. But only branch circuits?

I don't see how the exception can add the terms "box" and "conduit body" to the actual rule. Sure it does imply that, but it does not change the fact that the rule uses the term "enclosure".

Also note the requirement starts with neutral conductor, then stipulates the grounded circuit conductors is what the requirement applies to. In most cases the neutral is the grounded conductor, but what about when the grounded conductor is not a neutral (or vice versa)?

As written the rule only applies to all grounded circuit conductors, but does not apply to the rare neutral conductor that is not also a grounded conductor.

And just to nitpick, Exception No. 1 uses the if rather than where.

Perhaps should be something like...


If you like this verbiage, feel free to propose it for next cycle.

They say it usually takes 3 code cycles to get a new rule correctly written.

 

[Smart $]

I don't see how the exception can add the terms "box" and "conduit body" to the actual rule. Sure it does imply that, but it does not change the fact that the rule uses the term "enclosure".

Ok, I'll agree to imply...

As written the rule only applies to all grounded circuit conductors, but does not apply to the rare neutral conductor that is not also a grounded conductor.

But it only applies if there is a neutral... which is not the case for say a corner grounded delta. We could even debate a 120/208 1? system.

They say it usually takes 3 code cycles to get a new rule correctly written.

If that... :lol:

 

[don_resqcapt19]

...
But it only applies if there is a neutral... which is not the case for say a corner grounded delta. We could even debate a 120/208 1? system.
...

I can see the wording not applying the grounded conductor of a corner grounded system. Based on the current definitions I don't see any question as to the neutral conductor of a single phase 3 wire circuit that is supplied from a 208/120Y system.

 

[Smart $]

... Based on the current definitions I don't see any question as to the neutral conductor of a single phase 3 wire circuit that is supplied from a 208/120Y system.

Yes, it would be a technicality, especially in that case. However, it is entirely possible on the customer side of the service point to have a 120/208 1? 3W system, where the grounded conductor is not a neutral. The definition of neutral conductor and neutral point uses the term system. It is not required of the POCO to use a 208Y/120 3? 4W transformer secondary to supply it.

 

[don_resqcapt19]

How do you get 120/208 single phase if it does not originate from a 208/120Y system?

 

[Smart $]

How do you get 120/208 single phase if it does not originate from a 208/120Y system?

Just imagine two secondary windings instead of three. Not likely... but possible. However, even with it originating from a 3? system, the point is that may be on the POCO side of the service point and not under the scope of the NEC or its definitions. As such, the system starts at the service point.

As I said, debatable... and regardless, it definitely does not cover a corner grounded system.

 

[fmtjfw]

Neutral Conductor. The conductor connected to the neutral
point of a system that is intended to carry current under
normal conditions.

Neutral Point. The common point on a vee- or wye-connection in a
polyphase system or midpoint on a single-phase, 3-wire system,
or midpoint of a single-phase portion of a 3-phase delta
system, or a midpoint of a 3-wire, direct-current system.

Informational Note: At the neutral point of the system, the
vectorial sum of the nominal voltages from all other phases
within the system that utilize the neutral, with respect to the
neutral point, is zero potential.

So do we need to add a vee-connection in a polyphase system to cover the case of two hots and neutral in a 120/208 circuit. These are quite common in condos served by 120/208 Wye services.

Would we also need to fix the informational note?

 

[Smart $]

So do we need to add a vee-connection in a polyphase system to cover the case of two hots and neutral in a 120/208 circuit. These are quite common in condos served by 120/208 Wye services.

Would we also need to fix the informational note?

I say leave the def's as is and change the section wording.

 

[cowboyjwc]

By the time you get to the devices, it's usually pretty evident which neutral goes to which hot. The real reason for this section is when you are running multiple runs in one conduit. Read the section again, it says "within the panelboard or other point of origination." Point of origination, not point of termination.

 

[don_resqcapt19]

By the time you get to the devices, it's usually pretty evident which neutral goes to which hot. The real reason for this section is when you are running multiple runs in one conduit. Read the section again, it says "within the panelboard or other point of origination." Point of origination, not point of termination.

Are you sure you are looking at 200.4(B)?

 

[GoldDigger]

So do we need to add a vee-connection in a polyphase system to cover the case of two hots and neutral in a 120/208 circuit. These are quite common in condos served by 120/208 Wye services.

Would we also need to fix the informational note?

The way I look at it, regardless of how many of the phase wires are brought to a given point, the neutral (and usually grounded conductor) is the one which is a true neutral with respect to a three phase source.
(Does POCO ever provide a service or only two of three phases, or is that subdivison always made downstream of the service point? Smart $ used it as a hypothetical situation.)
What I would say however, is that a circuit containing only two of three possible phases and a neutral wire is a different kind of MWBC and the code explicitly recognizes that the way you count current carrying conductors is different in that case.
Two out of three phases plus neutral = 3 CCC. Three phases plus neutral also = 3 CCC.
Other rules relating to neutrals in a circuit or circuits may also have to be interpreted differently.

Of course the fact that the NEC, in 210.4, uses the term MWBC but does not bother to define it is a source of some of the problems.

 

[don_resqcapt19]

Branch circuit, multiwire is defined in Article 100. There is confusion between the neutral used with a MWBC and a common neutral.

 

[GoldDigger]

Branch circuit, multiwire is defined in Article 100. There is confusion between the neutral used with a MWBC and a common neutral.

Silly me, looking under M. :slaphead:

 

[cowboyjwc]

Are you sure you are looking at 200.4(B)?

Oops sorry I was thinking of 210.4(B) the handle ties, someone was asking about identifying the neutral conductors, I thought, which is 210.4(D) and I saw infinity quote 210.4(B)