The original ROP for the 2008 version was submitted by Mike Holt. It was then butchered in the ROC to substantially change it.
The result was deleted in 2011.
2008 ROP
8-104 Log #1349 NEC-P08 Final Action: Accept
(358.30(C))
________________________________________________________________
Submitter: Mike Holt, Mike Holt Enterprises
Recommendation: Add the following text to 358.30
(C) Unsupported raceways: Type EMT shall be permitted to be unsupported
where the raceway is not more than 900 mm (3 ft) in length and remains in
unbroken lengths (without coupling). Such raceway shall terminate in an outlet
box, junction box, device box, cabinet, or other termination at each end of the
raceway.
Substantiation: Unsupported raceways are violations of the Code that occur
everyday. As written, a 3 inch length of conduit between enclosures is required
to be supported, despite the fact that it adds little if any structural value to the
system. Quite often, particularly with conduit nipples, securing and supporting
a raceway shorter than 36 inches is not possible. Furthermore, securing and
supporting is of little value on lengths less than 36 inches where the conduit
terminates at a box on each end, where the box is installed and supported in
compliance with its applicable Code section.
This proposal is written with the parallel effect of Code sections that have
been strived for in chapter 3, and matches the numbering system used in the
Cable Articles. It also uses existing text taken from both the Cable Articles and
the Raceway Articles.
Panel Meeting Action: Accept
Number Eligible to Vote: 12
Ballot Results: Affirmative: 10 Negative: 2
Explanation of Negative:
DABE, J.: See my comment for 8-9.
HUMPHREY, D.: This proposal does not address other issues that may
have a direct impact on the durability of the electrical installation. The affects
of weight and vibration on concentric and eccentric knockouts at each end
of a three foot run between pieces of equipment, a scenario that would be
frequently in many electrical installations, may compromise the strength of the
installation. The raceway having even a single point of support would help to
mitigate these deleterious affects. In addition, the EMT installation in question
may be used as an equipment grounding conductor and any loosening that
could occur would serve to compromise the equipment grounding function
of the raceway. 300.11 further requires that raceways be securely fastened in
place. I would assert that this proposal would conflict with the requirements
of 300.11. In summation, depending on connectors, double locknuts etc. to
support and secure this up to 36 in. installation especially where concentric or
eccentric knockouts are encountered is dubious at best. 36 in. should provide
ample space in which to install normal supporting and securing hardware. A
proposal involving a shorter distance and where no concentric or eccentric
knockouts are encountered may be in order.
2008 ROC
8-57 Log #784 NEC-P08 Final Action: Accept
(358.30(C))
____________________________________________________________
Submitter: David G. Humphrey, Midlothian, VA
Comment on Proposal No: 8-104
Recommendation: Revise text to read as follows:
Where oversized, concentric or eccentric knockouts are not encountered,
Type EMT shall be permitted to be unsupported where the raceway is not more
than 900 mm (3 ft) 450 mm (18 in.) and remains in unbroken lengths (without
coupling). Such raceways shall terminate in an outlet box, device box, cabinet,
or other termination at each end of the raceway.
Substantiation: The existing text does not address issues that could have
a direct negative impact on the durability of the installation. The affects of
weight and vibration of the raceway, especially with larger raceway sizes,
may cause loosening at the raceway termination points. This loosening
would certainly impose an impediment to the raceways ability to safely carry
the maximum fault current likely to be imposed on the raceway. Reducing
the length to 450 mm (18 in.) would half the weight of the raceway in the
current text, and still provide ample room to install normal supporting and
securing hardware for longer lengths. Prohibiting unsupported raceways where
oversized, concentric, or eccentric knockouts are encountered would serve to
maintain the integrity of the equipment grounding function of the raceway.
In summation, the proposed revised text would meet the submitter’s intent
and address system durability issues.
Panel Meeting Action: Accept
Number Eligible to Vote: 12
Ballot Results: Affirmative: 11 Negative: 1
Explanation of Negative:
GRIFFITH, M.: Panel action on this Comment should have been to “Reject”
rather than to “Accept” for the following reasons:
1. The new language suggesting an 18 in. limit completely changes the intent
of the original proposal which was to clarify a widespread practice in industry
that is already implied to be acceptable by existing code language and for
which there is no evidence to change.
2. The spacing of 18 in. is new material that has not had public review and is
not substantiated.
3. The limitation to installations “where oversized...knockouts are not
encountered” has not been substantiated. In addition, concerns about knockouts
can be addressed by any of several installation methods representing good
workmanship that result in adequate support.
Panel action on the original Proposal 8-104 should continue to apply.
8-59 Log #1398 NEC-P08 Final Action: Accept in Principle in Part
(358.30(C))
____________________________________________________________
Submitter: James M. Imlah, City of Hillsboro
Comment on Proposal No: 8-104
Recommendation: Revise text to read as follows:
(c) Unsupported raceways: Type EMT shall be permitted to be unsupported
where the raceways is not more than 600 mm (2 ft) 900 mm (3 ft) in length and
remains in unbroken lengths (without coupling). Such raceway shall terminate,
where oversized, eccentric or concentric knockout are not encountered in an
outlet box, junction box, device box, cabinet, or other termination at each end
of the raceway.
Substantiation: This allowance should only be allowed for 24” nipples or
less in length. Many times EMT nipples, as described in Table 9 Note 4,
are installed for the intent of allowing additional conductor conduit fill. By
following the 24” length of this note for nipples provides consistency for short
sections of raceway being installed and meet submitters intent. Additionally,
support shall be installed if oversized, eccentric, or concentric knockouts are
encountered to maintain assured grounding and bonding continuity due to
vibration or loose oversized knockouts.
Panel Meeting Action: Accept in Principle in Part
Panel Statement: The panel action on Comment 8-57 satisfies the
eccentric or concentric issue of the submitter; however, the panel rejects the
recommendation to increase the unsupported length to 2 feet.
Number Eligible to Vote: 12
Ballot Results: Affirmative: 11 Negative: 1
Explanation of Negative:
GRIFFITH, M.: Panel action should have been to “Reject” this comment.
There is no substantiation for the limit(s) imposed by the submitter’s suggested
revision. See also my Explanation of Negative Vote on Comment 8-57.
