I. General
sembly, metric designator 16 through 27 (trade size
Vi through 1) conduit.
(7) For encasement in concrete where listed for direct
burial and installed in compliance with 356.42.
356.12 Uses Not Permitted. LFNC shall not be used as follows:
(1) Where subject to physical damage
356.1 Scope. This article covers the use, installation, and construction specifications for liquidtight flexible nonmetallic conduit (LFNC) and associated fittings.
356.2 Definition.
Liquidtight Flexible Nonmetallic Conduit (LFNC). A race- way of circular cross section of various types as follows:
(1) A smooth seamless inner core and cover bonded to- gether and having one or more reinforcement layers between the core and covers, designated as Type LFNC-A
(2) A smooth inner surface with integral reinforcement within the conduit wall, designated as Type LFNC-B
(3) A corrugated internal and external surface without integral reinforcement within the conduit wall, designated as LFNC-C
LFNC is flame resistant and with fittings and is ap- proved for the installation of electrical conductors.
FPN: FNMC is an alternative designation for LFNC.
356.6 Listing Requirements. LFNC and associated fit- tings shall be listed.
II. Installation
356.10 Uses Permitted. LFNC shall be permitted to be used in exposed or concealed locations for the following purposes:
FPN: Extreme cold may cause some types of nonmetallic conduits to become brittle and therefore more susceptible to damage from physical contact.
(1) Where flexibility is required for installation, operation, or maintenance.
(2) Where protection of the contained conductors is re- quired from vapors, liquids, or solids.
(3) For outdoor locations where listed and marked as suitable for the purpose.
(4) For direct burial where listed and marked for the purpose.
(5) Type LFNC-B shall be permitted to be installed in lengths longer than 1.8 m (6 ft) where secured in accordance with 356.30.
(6) Type LFNC-B as a listed manufactured prewired as-
(2) Where any combination of ambient and conductor temperatures is in excess of that for which the LFNC is approved
(3) In lengths longer than 1.8 m (6 ft), except as permitted by 356.10(5) or where a longer length is approved as essential for a required degree of flexibility
(4) Where the operating voltage of the contained conductors is in excess of 600 volts, nominal, except as permitted in 600.32(A)
(5) In any hazardous (classified) location, except as permitted by other articles in this Code
356.20 Size.
(A) Minimum. LFNC smaller than metric designator 16 (trade size Vi) shall not be used unless permitted in
356.20(A)(1) or (A)(2) for metric designator 12 (trade size Vs.).
(1) For enclosing the leads of motors as permitted in
430.245(B)
(2) In lengths not exceeding 1.8 m (6 ft) as part of a listed assembly for tap connections to luminaires as required in 410.117(C), or for utilization equipment
(B) Maximum. LFNC larger than metric designator 103 (trade size 4) shall not be used.
FPN: See 300.1(C) for the metric designators and trade sizes. These are for identification purposes only and do not relate to actual dimensions.