Floating Shield - Johnson Controls IFC-200 Wiring Manual

Floating Shield

3.5 Floating Shield
If using shielded wire with IFC-320, IFC2-640/E, IFC-640/E, IFC2-3030, IFC-3030,
LCM-320, LEM-320, JLIB-200A and JLIB-400
Twisted-unshielded wire is recommended for IFC-320/E/C, IFC2-640/E, IFC-640/E, IFC2-3030,
IFC-3030, LCM-320, LEM-320, JLIB-200A and JLIB-400. If twisted-shielded pair wire is used in
these installations, use a floating shield to terminate the wire. The following precautions must be
met:
• If the SLC is more than 3000 ft. (914.4 m), divide the shield into floating segments of less than
1000 ft. (304.8 m).
• To divide the shield wire into floating segments, cut shield even with jacket and tape as shown:
NOTE: Using shielded wire in applications where it is not recommended will reduce the maximum
SLC length. If shielded wire must be used where not recommended, failing to float the ends will
reduce the maximum SLC length even further.
Johnson Controls, Inc. SLC Wiring Manual — P/N 51870:G 04/23/2009
Tape
Figure 3.4 Floating the Shield
Shielded Wire Termination
25