Cabling Procedure - Emerson Liebert NX 480V User Manual

2.1.7

Cabling Procedure

CAUTION
!
The operations described in this section must be performed by authorized electricians or
qualified technical personnel. If you have any difficulties, contact your local Liebert
representative or Liebert Global Services.
NOTE
Hydraulic pressure pliers, combinative tools and piston ring pliers should be used to connect
AC wiring.
Once the equipment has been positioned and secured for operation, and the battery and ground col-
lars have been connected (see 2.1.4 - Cable Connections), connect the power cables as described
below. (Study the reference drawing in 6.0 - Installation Drawings.)
1. Verify that all incoming high and low voltage power circuits are de-energized and locked out or
tagged out before installing cables or making any electrical connections.
2. Remove the front protective cover to gain easier access to the connections busbars.
3. Connect the safety ground and any easier bonding ground bus cables to the copper ground busbar
located on the bottom of the equipment below the power connections. All cabinets in the UPS
system must be connected to the user's ground connection.
NOTE
The grounding bonding arrangement must comply with the National Electrical Code and all
applicable local codes.
4. Identify and make power connections with incoming cables according to Steps 5 through 9.
Common Input Connections
5. For common bypass and rectifier inputs, connect the AC input supply cables between the power
distribution panel and the UPS input busbars (A-B-C terminals) and tighten the connections to
88 lb-in. (10 N-m) using the M8 bolt provided.
Dual Input Connections
6. For the bypass, connect the AC input supply cables between the power distribution panel and the
UPS input busbars (A-B-C terminals) and tighten the connections to 88 lb-in. (10 N-m) using the
M8 bolt provided.
7. For the Rectifier Input, connect AC input supply cables between the power distribution panel and
the UPS input circuit breaker (A-B-C terminals).
NOTE
Both the rectifier and bypass feeds MUST come from the same utility source.
Output System Connections—Ensure Correct Phase Rotation
8. Connect the system output cables between the UPS output busbars (A-B-C terminals) and the
critical load and tighten the connections to 88 lb-in. (10 N-m) (M8 bolt).
WARNING
!
If the load equipment will not be ready to accept power on the arrival of the commissioning
engineer, then ensure that the system output cables are safely isolated.
Observe the battery cable polarity. Be sure that the battery connector is made with the cor-
rect polarity.
9. Refit all protective covers removed for cable installation
14
Electrical Connections