392.30(B) Cables and Conductors.
Code Change Summary: New requirements for cable ties used to support cables in a cable tray.
A common method used to secure and support cables in a cable tray is a cable tie or zip tie.
Not all cable ties are created equal. Some have only been evaluated to secure or position a cable. UL certifies a cable tie to UL 62275 as a “cable positioning device”.
The information listed below can be found using UL Product iQ under product category ZODZ: (Pay close attention to the last paragraph below).
RATINGS
Type Designations for Products Investigated to ANSI/UL 62275
- Type 2 — A Type 2 product retains 100% of its declared loop tensile strength (cable ties) or declared mechanical strength (fixing devices) after test conditions. The declared maximum operating temperature for products designated and marked as "Type 2" is based solely on performance criteria in ANSI/UL 62275. The polymeric material comprising the product has not been separately investigated for long-term thermal properties according to ANSI/UL 746B, "Polymeric Materials - Long Term Property Evaluations."
- Type 21 — A Type 21 product retains 100% of its declared loop tensile strength (cable ties) or declared mechanical strength (fixing devices) after test conditions. The declared maximum operating temperature for products designated and marked as "Type 21" is limited to the Relative Thermal Index - Strength (RTI - Strength) at 1.5 mm (0.06 in.) thickness for the polymeric material that comprises the product. The RTI - Strength for the material is determined by separate investigation for long-term thermal properties according to ANSI/UL 746B, and the declared maximum operating temperature of the product is based on the performance criteria in ANSI/UL 62275.
- Type 2S and Type 21S — Type 2S and Type 21S products meet the same requirements as Type 2 and Type 21 products, respectively, but have been additionally investigated for use as primary support for a flexible conduit, flexible tubing, or cable in accordance with the NEC®. Such products may also be marked "Support" in lieu of the "S" designation.
In the 2020 NEC®, cable ties used to support cables in a cable tray shall be listed, identified for the application and for securement and support. This aligns with similar language in other Chapter 3 articles such as 311, 320, 337, 330, 334, 348, and 393.
Below is a preview of the NEC®. See the actual NEC® text at NFPA.ORG for the complete code section. Once there, click on their link to free access to the 2020 NEC® edition of NFPA 70.
2017 Code Language:
392.30(B) Cables and Conductors. Cables and conductors shall be secured to and supported by the cable tray system in accordance with (1), (2) and (3) as applicable:
(1) In other than horizontal runs, the cables shall be fastened securely to transverse members of the cable runs.
(2) Supports shall be provided to prevent stress on cables where they enter raceways from cable tray systems.
(3) The system shall provide for the support of cables and raceway wiring methods in accordance with their corresponding articles. Where cable trays support individual conductors and where the conductors pass from one cable tray to another, or from a cable tray to raceway(s) or from a cable tray to equipment where the conductors are terminated, the distance between the cable trays or between the cable tray and the raceway(s) or the equipment shall not exceed 1.8 m (6 ft). The conductors shall be secured to the cable tray(s) at the transition, and they shall be protected, by guarding or by location, from physical damage.
2020 Code Language:
392.30(B) Cables and Conductors. Cables and conductors shall be secured to and supported by the cable tray system in accordance with (1), (2), (3), and (4) as applicable:
(1) In other than horizontal runs, the cables shall be fastened securely to transverse members of the cable tray.
(2) Supports shall be provided to prevent stress on cables where they enter raceways from cable tray systems.
(3) The system shall provide for the support of cables and raceway wiring methods in accordance with their corresponding articles. Where cable trays support individual conductors or multiconductor cables and where the conductors or multiconductor cables pass from one cable tray to another, or from a cable tray to raceway(s) or from a cable tray to equipment where the conductors are terminated, the distance between the cable trays or between the cable tray and the raceway(s) or the equipment shall not exceed 1.8 m (6 ft). The conductors shall be secured to the cable tray(s) at the transition, and they shall be protected, by guarding or by location, from physical damage.
(4) Cable ties shall be listed and identified for the application and for securement and support.