Liebert NX UPS System user manual Cable Termination, Common Input Connections

Single Module UPS Installation

1.6.1Cable Termination

NOTE

The operations described in this section must be performed by authorised electricians or qualified technical personnel. If you have any difficulties, do not hesitate to contact our Customer Service and Support Department. See the back page of this manual for contact information.

Once the equipment has been finally positioned and secured, connect the power cables as described in the following procedure.

Refer to the appropriate cable connection drawing in 4.0 - Installation Drawings.

1.Verify that the UPS equipment is isolated from its external power source and all the UPS power isolators are open. Check that these supplies are electrically isolated and post any necessary warning signs to prevent their inadvertent operation.

2.Open the door to the UPS cabinet and remove the front protective cover to gain access to the connections bars.

3.Connect the safety earth and any necessary bonding earth cables to the copper earth busbar located on the floor of the equipment below the power connections. All cabinets in the UPS must be connected to the user’s ground connection.

NOTE

The earthing and neutral bonding arrangement must be in accordance with local and national codes of practice.

Identify and make power connections for incoming cables according to one of the two procedures below, depending on the type of installation.

Common Input Connections

4.For common bypass and rectifier inputs, connect the AC input supply cables between the mains distribution panel and the UPS input (mA-mB-mC-N terminals) and tighten the connections to 5Nm (M6 Bolt). Ensure correct phase rotation.

Split-Bypass Connections

5.If a split-bypass configuration is used, connect the AC input supply cables to the rectifier input busbars (mA-mB-mC-N terminals) and the AC bypass supply cables to the bypass input (bA-bB-bC-N terminals) and tighten the connections to 5 Nm (M6 Bolt). Ensure correct phase rotation.

NOTE

For split-bypass operation, ensure that the linking busbars between bypass and rectifier input are removed.

The AC input and the AC bypass supplies must be referenced to the same neutral point.

Frequency Converter Mode

If a frequency converter configuration is used, connect the AC input supply cables to the rectifier input busbars (U1-V1-W1-N terminals) to 5Nm for M6 bolts, to 13Nm for M8 bolts or to 26Nm (M10 bolt). Ensure correct phase rotation and tighten the connections. There will not be any AC bypass supply cables to the bypass input (U3-V3-W3-N terminals).

NOTE

For frequency converter operation, ensure that the linking busbars between bypass and rectifier input are removed.

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