Vertiv Liebert MCM080 - Page 51

3. Primary High-Voltage Entrance—Two knockouts, each 7/8” (22.2mm) diameter, located at the
bottom of the enclosure.
4. SPD Field Connection Terminals—High-voltage surge protective device (SPD) terminals. SPD
is an optional device.
5. CANbus Terminal Connections—Field terminals for CANbus cable connection.
• 5A is the CANbus connectors
TB49-1 is the input terminal for CANbus high.
TB49-3 is the input terminal for CANbus low.
TB50-1 is the output terminal for CANbus high.
TB50-3 is the output terminal for CANbus low.
Each CANbus cable shield is connected to terminal “SH;” seeCANbus Shield Terminal—
Terminal for field shield connection of the CANbus field-supplied cables. The shield of
CANbus field-supplied cables must not be connected to ground at the condenser. below
below.
• 5B is the “END OF LINE” jumper.
• 5C is the CANbus “DEVICE ADDRESS DIP SWITCH.” CANbus cable not by Vertiv™. See
requirements in Notes on Electrical Connections on page43.
6. Remote Unit Shutdown—Replace exiting jumper between Terminals TB38-1 and TB38-2 with
field-supplied, normally closed switch having a minimum 75VA, 24VAC rating. Use field-
supplied Class1 wiring. (This is an optional feature.)
7. Alarm Terminal Connections
a. Common Alarm Relay indicates when any type of alarm occurs. TB74-1 is common; TB74-
2 is normally open; and TB74-3 is normally closed. 1A 24VAC is the maximum load. Use
field-supplied Class1 wiring.
b. Shutdown Alarm Relay indicates when condenser loses power or when a critical alarm has
occurred that shuts down the condenser unit. TB74-4 is common; TB74-5 is normally
open; and TB74-6 is normally closed. 1 Amp 24VAC is the maximum load. Use
field-supplied Class1 wiring.
8. Indoor Unit Interlock and SPD Alarm Terminals
a. On any call for compressor operation, normally open contact is closed across Terminals
70 and 71 for Circuit 1 and normally open contact is closed across Terminals 70 and 230
for Circuit 2 from indoor unit.
b. During SPD alarm, normally open contact is closed across Terminals 12 and 13. (SPD is an
optional device.)
9. CANbus Shield Terminal—Terminal for field shield connection of the CANbus field-supplied
cables. The shield of CANbus field-supplied cables must not be connected to ground at the
condenser.
10. Primary Low-Voltage Entrance—One knockout, 7/8” (22.2mm) diameter, that is free for
customer low-voltage wiring.
11. SPD entrance—One knockout, 7/8” (22.2mm) diameter at the bottom of the enclosure.
(High-voltage surge protective device is optional.)
Vertiv | Liebert® MC™ Installer/User Guide | 51