One of the major Code defects in my current house that I want to rectify at some point is the fact that the (only) panelboard is mounted too high up on the wall (the current panelboard's service disconnect handle is around the 6'7" limit). Since the panelboard is a 60+ year old, all-fuse Wadsworth that is already short on circuit spaces for the house — what is suspected to be the air conditioner circuit breaker is mounted in a cutout box, sans cover, above the panelboard — replacement with a modern unit seems like the cleanest option.
However, this creates a problem — the existing service-entrance conductors likely don't have enough length to reach the new panelboard location, and likewise for the branch circuit conductors entering the panelboard. So, I was thinking that the ideal solution to the problem would be to use an auxiliary gutter atop the panelboard to house splices between "pigtails" extending from the panelboard to their mating service-entrance and branch-circuit conductors, thus providing a neatly packaged solution without having to abuse the old panelboard cabinet as a junction box.
However, NEC 230.7 prohibits commingling service conductors with non-service conductors in the same "raceway or cable".
230.7 Other Conductors in Raceway or Cable.
Conductors other than service conductors shall not be installed in
the same service raceway or service cable.Exception No.1: Grounding electrode conductors and
equipment bonding jumpers or conductors.Exception No.2: Load management control conductors
having overcurrent protection.
This raises two questions, though. First, the Code uses "service-entrance conductor" instead of "service conductor" to presumably refer to the conductor from the meter base to the service disconnect with "service conductor" referring to the utility's conductors up to the meter, which would mean that under my interpretation, the commingling issue is moot. However, there's also the interpretation that a "service-entrance conductor" is a kind of "service conductor", which'd mean that 230.7 would apply to "service-entrance conductors" as well.
Furthermore, is an auxiliary gutter a raceway? One would think not, since they do not follow raceway fill rules, are authorized to contain splices and taps "by default" in 366.56 (which is not cited as an exception by 300.13 which normally prohibits splices in raceways) as well as 300.15(A), and follow different ampacity derating rules as per 366.23. However, I am sure that someone who just looked at the Article 100 definition of "raceway" by itself would see no reason it wouldn't apply to auxiliary gutters:
Raceway. An enclosed channel of metallic or nonmetallic
materials designed expressly for holding wires, cables, or bus-
bars, with additional functions as permitted in this Code.
Finally, in 366.2, the Code definition of what an auxiliary gutter is designed to be used with refers to "meter centers, distribution centers, switchgear, switchboards, and similar points of wiring systems".
Metallic Auxiliary Gutter. A sheet metal enclosure used
to supplement wiring spaces at meter centers, distribution
centers, switchgear, switchboards, and similar points of
wiring systems. The enclosure has hinged or removable
covers for housing and protecting electrical wires, cable,
and busbars. The enclosure is designed for conductors to be
laid or set in place after the enclosures have been installed
as a complete system.
Does that phrase include panelboards (including residential-type panelboards/load centers)? Or is using an auxiliary gutter with a panelboard/load center a Code violation as the gutter suddenly ceases to be a gutter by way of what it's mated to, leaving you with wires and splices in something that's not any kind of enclosure the Code recognizes?
Best Answer
It may be Code, but that doesn't mean it's a wise idea!
First off, I was under a mistaken impression about service-entrance conductors, so I'll clear that up now. It turns out that the Article 100 definition of "service conductors" includes both "service-entrance conductors" from the service drop/lateral splice to the service disconnect and "service drop conductors" that go from the utility transformer or service tap ("service point" in the Code) to the drop/lateral splice that connects them to the service-entrance conductors.
Second, an auxiliary gutter is not a raceway (unlike the physically similar product known as "wireway") -- this is based on the informational note to the Art. 100 definition of "raceway":
and the fact that 366.2's definitions refer to auxiliary gutters as enclosures, not "raceways".
This means that the 230.7 prohibition does not apply to auxiliary gutters, as the service-entrance conductors and the branch circuit conductors are not in the same "cable or raceway". However, the intent of 230.7 is to keep overcurrent-protected conductors away from unprotected conductors, and my proposed configuration would not provide that segregation.
Finally, in practice, auxiliary gutters are used with panelboards as they are similar in function to switchboards or distribution centers.
Options for similar situations to mine
If you don't want to do a dumb thing that your inspector may or may not flag as it's not against Code, you have two options in a similar situation to mine:
This is what Harper did to recover from his encounter with some very nasty copper thieves. This works provided you can get length in the existing cables to route them to multiple distribution boxes, and enough box space to accommodate all the splices (in addition to 4" square boxes for branches and feeders, Harper had to use a pair of 10" square NEMA boxes for incoming wiring).
This was Ed Beal's solution to having a feeder, branch circuits, and data wires in the same gutter -- partitions can be used to provide separated spaces within the gutter for each type of wiring. This is similar to how boxes that contain both mains and Class II or data wiring are partitioned to separate the high and low voltage sides from each other.
This has the advantage that all the wires can be routed to a single, existing point instead of having to be spread apart to route to many junction boxes, but is costlier as it may require a larger gutter to accommodate the fills within the various partitions.