Engineering Documentation

Appendix A – Discontinued Products
Terminal Control Unit (TCU)
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Terminal Control Unit (TCU)
NOTE:
The TCU is no longer available for new sales. Information in this section is for
reference only.
Wire Type Requirements
TCU Wire Type Requirements.
Circuit Type Class Wire Type (AWG) Distance
2
Conduit Sharing
1
AC line power
(to field panel)
Power No. 12 to No. 14,
No. 12 THHN
Check local codes Check local codes
Digital Output 1 Check local codes Check local codes Check local codes
Digital Output 2 Check local codes Check local codes Check local codes
Line Volt Relay Module; 5-
conductor cable to module
2
No. 22
5-conductor cable
150 ft (46 m)
Class 1 and 2
(check local codes)
Digital Input 2 No. 22
5-conductor cable
150 ft (46 m) Class 1 and 2
(check local codes)
Analog Input Thermistors 2 No. 22
5-conductor cable
100 ft (30.5 m) Class 1 and 2
(check local codes)
Actuator Output 2
No. 22
5-conductor cable
150 ft (46 m)
Class 1 and 2
(check local codes)
Power Trunk 2 No. 14 THHN or
No. 14 TP
180 ft (55 m)
2
Class 1 and 2
(check local codes)
1)
Conduit sharing rules were determined through EMI and shared conduit testing. These rules indicate wiring methods that have
no adverse affect on the proper operation of the equipment, but do not necessarily indicate compliance with local codes.
2)
Distances depend on transformer location. Install 100 VA transformers near the most convenient line voltage sources to
minimize line voltage wiring costs. Use one 100 VA transformer for every eight MPUs. (180 ft using 14 AWG wires is worst
case).
Power Source Requirements
TCUs can be powered in three ways. Correct sizing and fusing must be maintained for
each of these powering techniques:
● Individual transformer using a transformer rated for Class 2 service.
● Power trunk. For more information, see the section Power Trunk Guidelines
[➙ 64].
● Low voltage source of the device the controller is controlling (for example, fan
powered boxes, electric room heat, fan coils, and heat pumps).
CAUTION
The phase of all devices on a power trunk must be identical.
Phase differences can destroy equipment. Any relays, EPs, or contactors sharing
power must be clamped with MOVs at their locations.