Emerson 115-120 Manuel D’Utilisation

When the Liebert BDC is in Bypass mode, it provides an alternate path for power to the connected 

equipment. Should the UPS need to be taken out of service for limited maintenance or repair, manual 

activation of the bypass will cause an immediate transfer of the equipment from the UPS inverter to 

the bypass source. In this mode, power will still be supplied to the UPS; however, the load is NOT 

protected by the UPS. 

When the Liebert BDC is in Maintenance mode (MBB closed; BIB/MIB open), it provides an alternate 

path for power to the connected equipment should the UPS need to be taken out of service for limited 

maintenance or repair. In this mode of operation, no power is supplied to the UPS and the load is 

NOT protected by the UPS.

This Liebert BDC may be mounted to the left of the UPS or installed as a stand-alone unit. In either 

case, ensure that the unit is in a well-ventilated area and that there is clearance for access to the 

switches and cable connections as required by national and local codes.

Be sure that the unit is not connected to any AC utility power source or UPS before installing any 

wiring to this unit. This Liebert BDC should be installed by a qualified / certified electrician.

Plates cover the input and output terminals on the front of the Liebert BDC (see Figure 26). Remove 

these and keep the screws and plates for reinstallation.

Risk of electrical shock and arc flash. Can cause property damage, injury and death.
Read this section thoroughly before attempting to install wiring to this unit. Read and 

comply with all warnings and cautions in this manual.