Watlow CPC400 - Manual (Page 34)

Chapter 2: Installation CPC400 Series User’s Guide
20 Watlow Anafaze Doc. 0600-2900-2000
System Wiring
Successful installation and operation of the control system
can depend on placement of the components and on selec-
tion of the proper cables, sensors and peripheral compo-
nents.
Routing and shielding of sensor wires and proper ground-
ing of components can insure a robust control system. This
section includes wiring recommendations, instructions for
proper grounding and noise suppression, and consider-
ations for avoiding ground loops.
WARNING! To reduce the risk of electrical shock, fire, and
equipment damage, follow all local and national
electrical codes. Correct wire sizes, fuses and
thermal breakers are essential for safe operation
of this equipment.
CAUTION! Do not wire bundles of low-voltage signal and
control circuits next to bundles of high-voltage ac
wiring. High voltage may be inductively coupled
onto the low-voltage circuits, which may damage
the controller or induce noise and cause poor
control.
Physically separate high-voltage circuits from
low-voltage circuits and from CPC400 hardware.
If possible, install high-voltage ac power circuits
in a separate panel.
Wiring Recommendations
Follow these guidelines for selecting wires and cables:
• Use stranded wire. (Solid wire can be used for fixed
service; it makes intermittent connections when you
move it for maintenance.)
• Use 20 AWG (0.5 mm 2 ) thermocouple extension wire.
Larger or smaller sizes may be difficult to install, may
break easily or may cause intermittent connections.
• Use shielded wire. The electrical shield protects the
signals and the CPC400 from electrical noise. Connect
one end of the input and output wiring shield to earth
ground.
• Use copper wire for all connections other than thermo-
couple sensor inputs.