Part I. General
- Scope. This article covers the use, installation, and construction specifications for messenger-supported wiring.
Insulated Conductor. For the purposes of this article, an insu‐ lated conductor includes the following:
- Conductor types described in 310.104, and
- Overhead service conductors encased in a polymeric material that has been evaluated for the applied nominal voltage.
Informational Note: Evidence of evaluation for the applied nominal voltage can be given by certification that the conduc‐ tors have met the requirements of ICEA S-76-474-2011, Standard for Neutral Supported Power Cable Assemblies with Weather-Resistant Extruded Insulation Rated 600 Volts.
Messenger-Supported Wiring. An exposed wiring support system using a messenger wire to support insulated conductors by any one of the following:
- A messenger with rings and saddles for conductor support
- A messenger with a field-installed lashing material for conductor support
- Factory-assembled aerial cable
- Multiplex cables utilizing a bare conductor, factory assem‐ bled and twisted with one or more insulated conductors, such as duplex, triplex, or quadruplex type of construc‐ tion
396.10 ARTICLE 398 — OPEN WIRING ON INSULATORS
Part II. Installation
396.10 Uses Permitted.
- Cable Types. The cable types in Table 396.10(A) shall be permitted to be installed in messenger-supported wiring under the conditions described in the article or section referenced for each.
- In Industrial Establishments. In industrial establishments only, where conditions of maintenance and supervision ensure that only qualified persons service the installed messenger- supported wiring, the following shall be permitted:
- Any of the conductor types shown in Table 310.104(A) or Table 310.104(B)
- MV cable
- Hazardous (Classified) Locations. Messenger-supported wiring shall be permitted to be used in hazardous (classified) locations where the contained cables and messenger-supported wiring are specifically permitted by other articles in this Code.
396.12 Uses Not Permitted. Messenger-supported wiring shall not be used in hoistways or where subject to physical damage.
- Support. The messenger shall be supported at dead ends and at intermediate locations so as to eliminate tension on the conductors. The conductors shall not be permitted to come into contact with the messenger supports or any structural members, walls, or pipes.
- Neutral Conductor. Where the messenger is used as a neutral conductor, it shall comply with the requirements of 225.4, 250.184(A), 250.184(B)(7), and 250.187(B).
- Equipment Grounding Conductor. Where the messenger is used as an equipment grounding conductor, it shall comply
Table 396.10(A) Cable Types
Cable Type Section Article
Medium-voltage cable 328
Metal-clad cable 330
with the requirements of 250.32(B), 250.118, 250.184(B)(8), and 250.187(D).
396.56 Conductor Splices and Taps. Conductor splices and taps made and insulated by approved methods shall be permit‐ ted in messenger-supported wiring.
396.60 Grounding. The messenger shall be grounded as required by 250.80 and 250.86 for enclosure grounding.