Rockwell Automation 2100 CENTERLINE Low Voltage Motor Control Centers - Manual (Page 45)

Rockwell Automation Publication 2100-IN012E-EN-P - February 2012 45
Installing Conduit and Cable Chapter 3
Securing Cables with Hardwood
In this example, a hardwood brace (maple hardwood) made for the specific
application is used. Holes are bored approximately the size of the cable diameter.
Several bolt holes are also bored the breadth of the hardwood brace. The brace is
cut in two pieces and is used as a clamp to secure the cables. Through bolts are
inserted into the brace and tightened so that cables are held tightly in place.
Figure 26 - Securing Cables with Hardwood
A second form of hardwood brace (not shown) is a yolk type in which the cables
are passed through. Holes should be small enough to provide a snug fit for the
cables. The connectors or lugs are attached to the cables and cables are bolted to
the terminals.
When using the hardwood bracing method and the short circuit current is less
than 42,000 A, cables should be braced every 12 in. (305 mm). When the short
circuit current is 42,000 A or greater, cables should be braced every 6 in.
(153 mm).
Incoming Line Brace
Allen-Bradley manufactures an incoming line brace similar to the hardwood
clamping-type brace. To order an incoming line brace, contact your local Allen-
Bradley sales office and reference assembly number 40113–848.
IMPORTANT Lugs should be installed so they are in line with each other and proper
spacing is used between phases. Hardware must be torqued per the
torque tables found on the enclosure door.