Cut Sheet

Series 3110
Armored Cable Connector
& Flexible Metal Conduit
Series 390
Anti-Short Bushing
Suggested Specifications for Armored Cable and Flexible Metal Conduit Fittings
• Armored cable (metal clad cable type
AC) and flexible metal conduit shall
conform to provisions of following
applicable standards:
Armored Cable…UL 4/ANSI
C33.9/CSA 22.2 No. 51
Flexible Metal Conduit…UL 1/ANSI
C33.92/WW-C-566/CSA 22.2 No. 56
Type of cable used and conductors
within flexible metal conduit shall
be suitable for conditions of use
and location.
• Where approved armored cable or
flexible metal conduit is used as an
equipment grounding conductor,
terminating fitting used shall be of
the grounding type as manufactured
by Thomas & Betts, series 3110
• Where armored cable or flexible
metal conduit terminates into a
threadless or threaded opening, it
shall be assembled with approved
fittings; fittings shall be of malleable
iron/steel construction, electro zinc
plated inside outside, equipped with
nylon insulated throat and shall be of
angled saddle type as manufactured
by Thomas & Betts, series 3110.
Direct bearing screw type fittings
shall not be used
• Suitable bushing as manufactured
by Thomas & Betts, series 422
or 390, shall be provided between
the conductors and armor
Metal Clad Cable, Armored Cable and Flexible Metal Conduit — continued
Flexible Metal Conduit — Ref. NEC Article 348
Flexible metal conduit can be used for exposed
or concealed work in dry locations. It can be
used for wet locations provided conductors
within are lead covered or other approved type.
Flexible metal conduit cannot be used
underground or embedded in poured concrete
or aggregate. With rubber covered conductors,
the conduit cannot be exposed to oil, gasoline
or other materials having a deteriorating effect
on rubber.
With minor exceptions use of flexible metal
conduit is not permitted in hoists, in storage
battery rooms and in any hazardous locations.
Use of flexible metal conduit is restricted to
systems under 600 volts.
According to NEC Article 350-5, flexible metal
conduit no longer than six feet and containing
circuit conductors protected by overcurrent
device rated for 20 amps or less is suitable
as a grounding means provided, it is terminated
in fittings approved for the purpose.
Flexible metal conduit longer than six feet
is permitted to be used as a grounding means
provided the conduit and the fitting are approved
for the purpose. To date, there is no flexible
metal conduit approved for the purpose by
the Underwriters Laboratories.
In Class I & II, Division 2 hazardous areas, the
conduit itself cannot be used as the grounding
means. A bonding jumper must be installed in
accordance with NEC Section 250.102. Flexible
metal conduit is available with steel or aluminum
armor in trade size
5
⁄16" to 4". With few exceptions
where
5
⁄16" and
3
⁄8" trade sizes are used, Code
prohibits use of conduit less than d" trade size.
Bends in concealed work are restricted to 360
degrees total. No angle connectors are permitted
in concealed raceway installations.
Portions of this section reprinted by
permission from NFPA 70-2005, National
Electrical Code
®
, Copyright
©
2004, National Fire
Protection Association, Boston, MA.
Please refer to the following for further details
and complete information:
1. NEC Article 348…Flexible Metal Conduit
2. UL 1, ANSI C33.92…Safety Standards
for Flexible Metal Conduit
3. UL 514B, Safety Standards for Outlet
Boxes and Fittings
4. A-A-50552…Federal Specification. Fittings
for Cable, Power, Electrical and Conduit,
Metal Flexible
5. WW-C-566…Federal Specification.
Conduit, Metal, Flexible
6. NEMA FB1…Standards Publication.
Fittings and Supports for Conduit
and Cable Assemblies
7. CEC 12-1100…Wiring Method (Rigid
& Flexible Conduit)
8. CSA C22.2 No. 56…Safety Standards for
Flexible Metallic Conduit and Liquid-Tight
Flexible Metal Conduit
9. CSA C22.2 No. 18…Safety Standards for
Outlet Boxes, Conduit Boxes and Fittings
Metal Clad Cable, Armored Cable and Flexible Metal
Conduit Fittings
A-156
United States
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