CMP-8 Raceways, Wireways, Busways, Gutters, Cable …grouper.ieee.org/groups/scc18/NFPA_70_NEC/NFPA_70_NEC_2011_Cy… · Report to IEEE SCC-18 February 2009 CMP-8 Raceways, Wireways,

NEC Panel 8Report to IEEE SCC-18 February 2009

CMP-8 Raceways, Wireways, Busways, Gutters,

Cable Tray, Etc. (per NEC Chapter 3)And

Tables 1-4 of Annex C (Conduit & Tubing)

M. Shan Griffith – PrincipalDuane Carlson - Alternate


ACTIONSTotal - 298 Proposals (Incl. 6 By Panel)205 – Rejected (R)55 – Accepted (A)29 – AIP4 – AP2 – APP3 – Referred to Other Panels


Split-Vote Proposals Requiring IEEE SCC-18 Direction -

- Support of Conduit Nipples (5) - A

- Addition of EGC in Conduit (3) - R- ‘Flexibility’ Clarified for FMC/LFMC (2) – R

(To Include ‘Vibration’)- Wire Mesh Cable Tray (1) - R

- S.C. Force Calcs for Tray Cable (2) – R

To Comment On or Oppose Panel Action


Support of Conduit Nipples (5 Proposals) - A

8-24a (IMC), 8-35 (RMC), 8-78 (PVC),

8-105 (RTRC), & 8-125 (EMT)

Delete Following Language (Added in 2008 NEC);

Where oversized, concentric or eccentric knockouts are not encountered, Type (IMC) shall be permitted to be unsupported where the raceway is not more than 450 mm (18 in.) and remains in unbroken lengths (without coupling). Such raceways shall terminate in an outlet box, junction box, device box, cabinet, or other termination at each end of the raceway.Previous IEEE Position Was to Support Present Text

(Oppose Panel Action?)


Addition of EGC in Conduit (3) – R

RMC / 8-39 (Section 344.60) Delete: ‘Rigid metal conduit is permitted to be an equipment ground.’

EMT / 8-129 & 8-130 (Section 358.60)8-129Delete: ‘358.60 Grounding. EMT shall be permitted as an equipment grounding conductor.’Insert: ‘358.60 Grounding. When equipment grounding is required, a separateequipment grounding conductor shall be installed in the raceway.’

8-130Revise to read ‘EMT shall (not) be permitted as an equipment groundingconductor.’

Traditional IEEE Position Should ‘Accept’ (Oppose Panel Action)


‘Flexibility’ Clarified for FMC/LFMC (2) – R(To Include ‘Vibration’)

FMC / 8-51 (Section 348.60)

LFMC / 8-65 (Section 350.60)Revise text as follows: “Where used to connect equipment where flexibility is required to minimize the transmission of vibration from equipment or to provide flexibility for equipment that requires movement after installation, an equipment grounding conductor shall be installed.”Panel Statement: Proposed changes do not improve clarity or content of existing text.

Both Should be Accepted (To Guide Design Toward NEC Compliance)

(Oppose Panel Action)


Wire Mesh Tray (1) – R

8-267 / Cable Tray Tables 392.9 & 392.10(A)This proposal is a table revising (adding additional tray widths) to be similar with NEMA VE 1, 4.3 (2 in., 8 in., 16 in., and 20 in.).

Substantiation: The 2 in., 4 in., 4 in., 8 in., 16 in., and 20 in. widths are often inquired regarding fill rates which are standard widths for wire mesh tray. Since these widths are not listed, it causes confusion, etc.

Panel Statement: The submitter's proposal introduced new information without any substantiation. The submitter's proposal has incorrect information in the data.

Should be Accepted w/Correction of Coefficients in Table 392.9. With NEMA Recognition & Widespread Use No Additional Substantiation is Needed

(Affirm w/Comment)


S.C. Force Calcs for Tray Cable (2) – RSection 392.8(D)8-265Revise text to: Single conductors shall be securely bound in circuit groups to prevent excessive movement due to fault-current magnetic forces unless single conductors are cabled together, such as triplexed assemblies. The restraint method employed shall protect the single conductors fromdamage due to the fault-current magnetic forces and be rated for the spacingbetween conductors and maximum available fault current.

8-266Delete Italics: Single conductors shall be securely bound in circuit groups toprevent excessive movement due to fault-current magnetic forcesunless single conductors are cabled together, such as triplexed assemblies.

Should IEEE Accept 8-266 (As Is or w/Modification)?


General Interest Proposals- Article 392 Re-write (Cable Tray)

No (Intentional) Technical Change- Cellular Concrete/Metal Floor R’way (8)

- Metal Floor Raceway (6)- Circuit Derating / Parallel

Conductor Sets (2)


General Interest Proposals (Cont.)

-Cellular Concrete/Metal Floor R’way (8)

- Metal Floor Raceway (6) Article 374By H.H. Robertson & ‘Associates’8-180, -181*, -182, -183, -184, & -185

Proposals seek to relax the standard ampacity de-rating factors aspresently applied to Metal Floor Raceway or to eliminate them altogetherfor installations involving 30, or less, conductors consistent with the requirements for Auxiliary Gutters (Art. 366), Metal Wireways (Art. 376)& Strut-Type Channel Raceway (Art. 384).

* - Carry-over from Last Code Cycle


General Interest Proposals (Cont.)-Cellular Concrete/Metal Floor R’way (8)

- Derating Limit / Parallel Conductor Sets (2)

8-179 (Concrete – 372.17) 8-186 (Metal – 374.17)

Proposal - Add Exception: Where more than one outlet on the samecircuit is individually supplied by one set of conductors it shall bepermitted to count only the current-carrying conductors of one such setof conductors for the purpose of ampacity adjustment.

Recommend IEEE Ballot Vote be to Accept (AIP) w/Modification



General Interest Proposals (Cont.)-Cellular Concrete/Metal Floor R’way (8)

- Derating Limit / Parallel Conductor Sets (2)

8-179 (Concrete – 372.17) 8-186 (Metal – 374.17)

AIP with Wording Modified as Follows –Add Exception: Where multiple outlets on the same circuit aresupplied by separate conductor sets it shall be permitted to countonly one such set of current-carrying conductors for the purpose ofampacity adjustment.

Recommend IEEE Ballot Vote be to Accept (AIP) w/Modification


Documents

CMP-8 Raceways, Wireways, Busways, Gutters, Cable …grouper.ieee.org/groups/scc18/NFPA_70_NEC/NFPA_70_NEC_2011_Cy… · Report to IEEE SCC-18 February 2009 CMP-8 Raceways, Wireways,