GE Industrial Solutions GE ZENITH SERIES MDU - Manual (Page 14)

Installation Procedures
GE Z ENITH C ONTROLS
MDU Owner’s Manual
601 S HILOH R OAD January 2013
Plano, TX 75074 Page 14
3.6. Torque Specifications
3.6.1. Structural Fasteners
Structural fasteners are typically used for fastening the MDU to a supplied floor stand or
concrete slab. If structural fasteners are required per assembly instructions, refer to the
table below for typical torque values. Tighten steel hardware parts (except electrical
connections) to the values given in the following table.
Bolt Diameter Tightening Torque (in-lb)
#8 (5/32”) 15
#10 (3/16”) 20
1/4” 120
5/16” 228
3/8” 396
7/16” 648
1/2” 936
3.6.2. MCCB’s, MCSW’s, Contactors, and Other Electrical Components
Always tighten electrical component (CBs, contactors, etc.) connections to the
manufacturer’s torque specifications furnished with the component. There are some
guidelines for electrical components if no manufacturer data is available. Tighten
connections using Belleville type (spring) washers until washers are flat.
3.7. Torque Value Quick Reference
Use the following as a reference only. Always check the breaker or component labeling and/or
instructions for proper torque values. DO NOT OVER TORQUE!
Always use the manufacturer’s hardware on CBs, contactors, etc. Once connections are torqued and
sealed, make sure that removable lug covers are reinstalled,
3.7.1. Standard Circuit Breakers (Mains & Sub-feeds)
Manufacturer Breaker Frame / Bolt Required Torque (ft-lb)
Square D
F Frame 6.7
K Frame 20.9
L Frame 31.3
M Frame 25.0
Cutler Hammer
F Frame 10.0
J Frame 22.9
K Frame 22.9 (Wire Smaller than 250 MCM)
K Frame 31.3 (Wire 250 MCM or larger)
ABB ISOMAX
Rear Lug Mounting Bolt
requires
S3 22.9
S4 22.9
S5 22.9
Rear Lug Mounting Bolt 9.2