Cabling Procedure - Emerson Liebert NX 10-30kVA Installation 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 7.0 - 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 left side panel 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 and neutral 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 11.
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
44 lb-in. (5 N-m) using the M6 bolt provided.
6. The input neutral cable must be connected to the input neutral busbar (N). See Figure 5.
Dual Input Connections
7. For 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 44 lb-in. (5 N-m) using the M6
bolt provided.
8. For Rectifier Input connect AC input supply cables between the power distribution panel and the
UPS input circuit breaker (A-B-C terminals)
9. The bypass and rectifier input neutral cables must be connected to the input neutral busbar (N).
See Figure 5.
NOTE
Both the rectifier and bypass feeds MUST come from the same utility source, except if the UPS
system includes either a configuration F or P external maintenance bypass cabinet.
Output System Connections—Ensure Correct Phase Rotation
10. Connect the system output cables between the UPS output busbars (A-B-C N terminals) and the
critical load and tighten the connections to 44 lb-in. (5 N-m) (M6 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.
13
Electrical Connections