Cut Sheet

Rigid and Intermediate Metal Conduit Fittings
Locknuts
Application
• To connect externally threaded conduit or connector
to a threadless opening in a box or enclosure
• To effectively bond conduit or connector to box or enclosure
Features
• Hardened steel/malleable iron/copper-free
aluminum construction
• Tightens without deformation
• Locknuts specially designed to:
(i) Provide extended reach for clamping
on thin boxes and enclosures
(ii) Cut through protective coating on box and
enclosure, thereby ensuring ground continuity
(iii) Permit tightening from outside
(iv) Prevent loosening under vibration
• 106 Series provided with a hardened cone point screw
Standard Material
140 Series & 106 Series
3
⁄8" thru 2" steel (hardened) 2
1
⁄2" thru 6"
Malleable Iron
All screws steel
141AL Series
All copper-free aluminum
Standard Finish
All steel and malleable iron locknuts, including electro zinc-plated
bonding screws and chromate coated all-aluminum locknut, degreased
Range
3
⁄8" through 6" conduit (All threads straight pipe [NPS]) (140 Series)
1
⁄2" through 4" conduit (106 Series & 141AL Series)
Listings/Compliances
UL (UL File No. E-23018)
CSA [catalog numbers 108, 109, 110 and 111. All 140 Series
except catalog number 140.] (LR-2884, LR-4484)
UL 514B
CSA C22.2 No. 18
NEMA FB1
NFPA 70
Federal Specification replaced by A-A-50553
Federal Standard H-28 (Threads)
Case Hardened Locknuts
Case hardened locknuts make fittings faster and easier to install. Case
hardened locknuts do not slip or turn, thereby protecting the biting edge.
Case hardened locknuts bite through paint into the enclosure, providing
excellent continuity of ground (typical T&B/Thomas & Betts fitting with case
hardened locknuts successfully passed minimum fault current of 10,000
amps RMS). Case hardened locknuts, when assembled in the intended
manner, will not vibrate loose, thereby ensuring excellent ground continuity.
140 Series
141AL Series
106 Series
A-4
United States
Tel: [phone]
800.816.7809
Fax: [phone]
Technical Services
Tel: [phone]
www.tnb.com