than metric designator 155 (trade size 6) shall not be used.
FPN: The trade sizes and metric designators are for identification purposes only and do not relate to actual dimensions. See
300.1(C).
355.22 Number of Conductors. The number of conductors shall not exceed that permitted by the percentage fill specified in Table 1, Chapter
9. Cables shall be permitted to be installed where such use is not prohibited by the respec- tive cable articles. The number of cables shall not exceed the allowable percentage fill specified in Table 1, Chapter 9.
355.24 Bends - How Made. Bends shall be so made that the conduit will not be damaged and the internal diameter of the conduit will not be effectively reduced. Field bends shall be made only with bending equipment identified for the purpose. The radius of the curve to the centerline of such bends shall not be less than shown in Table 2, Chapter 9.
355.26 Bends - Number in One Run. There shall not be more than the equivalent of four quarter bends (360 degrees total) between pull points, for example, conduit bodies and boxes.
355.28 Trimming. All cut ends shall be trimmed inside and outside to remove rough edges.
355.30 Securing and Supporting. RTRC shall be installed as a complete system in accordance with 300.18 and shall be securely fastened in place and supported in accordance with
355.30(A) and (B) or permitted to be unsupported in accordance with 355.30(C).
(A) Securely Fastened. RTRC shall be securely fastened within 900 mm (3 ft) of each outlet box, junction box, device box, conduit body, or other conduit termination. Conduit listed for securing at other than 900 mm (3 ft) shall be permitted to be installed in accordance with the listing.
(B) Supports. RTRC shall be supported as required in Table 355.30. Conduit listed for support at spacing other than as shown in Table
355.30 shall be permitted to be installed in accordance with the listing. Horizontal runs of RTRC supported by openings through framing members at intervals not exceeding those in Table 355.30 and securely fastened within 900 mm (3 ft) of termination points shall be permitted.
(C) Unsupported Raceways. Where oversized, concentric or eccentric knockouts are not encountered, Type RTRC 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, device box, cabinet, or other termination at each end of the raceway.
355.44 Expansion Fittings. Expansion fittings for RTRC shall be provided to compensate for thermal expansion and
Table 355.30 Support of Reinforced Thermosetting
Resin Conduit (RTRC)
Maximum
Spacing
Conduit Size Between
Supports
Metric
Designator Trade Size mm or m ft
16-27 '/2-1 900 mm 3
35-53 1 VAT-2 1.5 m 5
63-78 2'/2-3 1.8 m 6
91-129 3'/ 2-5 2.1 m 7
155 6 2.5 m 8
contraction where the length change, in accordance with Table 355.44, is expected to be 6 mm (]A in.) or greater in a straight run between securely