Key Changes in the 2014 NEC Code
Every three years the National Electrical Code® is revised and new standards are published. Suggestions for these changes come primarily from professional electrical contractors like you and reflect the changing way we use electricity, new products, and emerging technologies.
Among the more significant revisions in the 2014 NEC® Code are a change from 600- to 1,000-volt thresholds throughout as a result of the increasing adoption of wind and solar power generation. The 2014 Code also incorporates requirements for direct current (DC) systems and wiring throughout.
Other major changes are discussed below. The actual code change is in italics, with deleted sections indicated as strikethroughs, followed by an analysis of the changes.
Wiring Methods and Materials - Other Places Used for Environmental Air (Plenum)
Nonmetallic cable ties and other nonmetallic cable accessories used to secure and support cables shall be listed as having low smoke and heat release properties.
This new requirement was added to the end of Section 300.22(C)(1) and requires nonmetallic cable ties and other nonmetallic cable accessories to be specifically “listed” for installation in other spaces used for environmental air.
Outlet, Device, Pull, and Junction Boxes; Conduit Bodies; Fittings; and Handholes – Smaller Dimensions
Listed boxes or listed conduit bodies of dimensions less than those required in 314.28(A)(1) and (A)(2) shall be permitted for installations of combinations of conductors that are less than the maximum conduit or tubing fill (of conduits or tubing being used) permitted by Table 1 of Chapter 9.
Listed conduit bodies of dimensions less than those required in 314.28(A)(2) having a radius of the curve to the centerline not less than as indicated in Table 2, Chapter 9 for one shot and full shoe benders, shall be permitted for installations of combinations of conductors permitted by Table 1 of Chapter 9. These conduit bodies shall be marked to show they have been specifically evaluated in accordance with this provision.
Where the permitted combinations of conductors for which the box or conduit body has been listed are less than the maximum conduit or tubing fill permitted by Table 1 of Chapter 9, the box or conduit body shall be permanently marked with the maximum number and maximum size of conductors permitted.
This section was revised to eliminate the specific conductor marking requirements for listed conduit bodies of smaller dimensions having a radius of the curve to the centerline not less than as indicated in Table 2, Chapter 9. This is the same minimum radius of curve required for field bends in IMC, RMC, and EMT found in Sections 342.24, 344.24, and 358.24 respectively. Therefore, these are suitable for installations of combinations of conductors of the maximum conduit or tubing wire fill (of conduit or tubing being used) permitted by Table 1 in Chapter 9.
These designs greatly simplify wire fill calculations for conduit bodies for both design and inspection and do not require conductor size markings. The 2011 NEC® text in Section 314.28 (A) (3) was restrictive for these designs as it technically did not permit installation of the full Table 1, Chapter 9 wire fill for the conduit or tubing being used. These conduit body designs effectively negate the concern for wire jamming addressed in Informational Note No. 2 to Tables in Chapter 9.
Liquidtight Flexible Nonmetallic Conduit: Type LFNC - Uses Not Permitted
LFNC shall not be used as follows:
(1) Where subject to physical damage
(2) Where any combination of ambient and conductor temperatures is in excess of that for w