Emerson 480V Manuel D’Utilisation

The safety ground busbar is located below the Maintenance Bypass circuit breaker or to the right of 

the UPS Output breaker for 160-200KVA models as shown in Figure 4. The safety ground cable must 

be connected to the ground busbar and bonded to each cabinet in the system.
All cabinets and cable conduit should be grounded in accordance with local regulations.

For safety, it is necessary to install circuit breakers in the input AC supply and external battery bat-

tery cabinets, external to the UPS system. Given that every installation has its own characteristics, 

this section provides guidelines for qualified installation engineers with knowledge of operating prac-

tices, regulatory standards and the equipment to be installed.

• Protection from excessive overcurrents and short circuits in power supply input

External overcurrent protection for the AC output circuit is to be provided. See 5.4 - UPS Elec-

trical Characteristics and Table 9 for overload capacity.
When an external battery supply not made by Liebert is used, the customer must provide overcur-

rent protection for the battery circuit.

When wiring the UPS with dual inputs, the Rectifier input and the Bypass input must be pro-

tected separately. Size the breakers according to the input currents shown in Table 8.

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 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.

Failure to follow proper grounding procedures can result in electric shock hazard to personnel 

or the risk of fire, should a ground fault occur.

NOTE
Proper grounding significantly reduces electromagnetic interference problems in systems.

NOTE
The ground busbar is easily accessible when the lower protective cover plate is removed.

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 Services.

NOTE
Hydraulic pressure pliers, combinative tools and piston ring pliers should be used to connect 

NOTE
The grounding bonding arrangement must comply with the National Electrical Code and all