Article 348 Flexible Metal Conduit Type FMC

I. General





This is a circular raceway of helically wound, formed, interlocked metal strip.


Listing Requirements

Must be listed.

II. Installation


Uses Permitted

It can be used in exposed and concealed locations.


Uses Not Permitted

It cannot be used in wet locations unless approved for this and the liquid does not get into the conduit, in hoistways unless permitted by Section 620.21(A)(1), in storage battery rooms, in hazardous locations unless allowed by Sections 501.4(B) and 504.20, where materials might deteriorate conductors, underground or in poured concrete or aggregate, and where subject to physical damage.



Minimum size permitted is metric designator 12 (trade size 3/8). The use of metric designator 12 (3/8) is allowed for leads to motors [Section 430.145(b)], not longer than 1.8 m (6 ft.) as part of a listed assembly or taps to lighting fixtures [Section 410.67(C)] or utilization equipment, for manufactured wiring systems [Section 604.6(A)], in hoistways Section 620.21, and as permitted by Section 410.77(C) as part of a listed assembly to connect wired fixture sections. There are five exceptions. The maximum size permitted is metric designator 103 (trade size 4).


Number of Conductors

Cannot exceed the percentage fill of Table 1, Chapter 9. Cables can be used if not prohibited by cable articles. Cable cannot exceed the fill requirements of Table 1, Chapter 9.


BendsHow Made

Bends must not damage the conduit and must not reduce the internal diameter of the conduit. Bends can be made with auxiliary equipment manually. The radius of the curve to the centerline can not be less than that shown in Table 1, Chapter 9. Use the "Other Bends" column.


BendsNumber in One Run

The maximum number that is permitted is not more than 360 degrees in bends between pull points. The radius of curve of the inner edge of a field bend must comply with Table 346.10.




Securing and Supporting

Securely fasten within 300 mm (12 in.) of a termination point and supports must be not more than 1.4 m (4½ ft.) apart. There is a provision for supports through framing openings. There are four exceptions.


Couplings and Connectors


Splices and Taps

They can be made only in accordance with 300.15.


Grounding and Bonding

An equipment grounding conductor must be installed when the conduit is used to connect equipment where flexibility is needed. It can be used as an equipment grounding conductor where flexibility is not required in accordance with 250.48(5) or (6). The equipment grounding conductor must be installed in accordance with 250.134(B). Equipment bonding conductors must be installed in accordance with 250.102.

Article 90 Introduction


Wiring and Protection

Wiring Methods and Materials

Equipment for General Use

Special Occupancies

Special Equipment

Special Conditions


Annex C. Conduit and Tubing Fill Tables for Conductors and Fixture Wires of the Same Size

Annex D. Examples

Annex E. Types of Construction

Pocket Guide to the National Electrical Code 2005
Pocket Guide to the National Electrical Code(R), 2005 Edition (8th Edition)
ISBN: 0131480014
EAN: 2147483647
Year: 2004
Pages: 120 © 2008-2020.
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