Emerson AC4 User Manual

The Liebert AC4 requires 24VAC for proper operation. Liebert recommends using the optional 

Transformer Module manufactured by Liebert or another UL-approved class 2 power unit to obtain 

proper voltage. If the power unit is not a class 2 circuit, it must be protected with an IEC 5 x 20mm 

time lag 2A fuse. For information, consult your local dealer, Emerson representative or the Emerson 

Network Power Liebert Worldwide Support Group.

To connect electrical power:
1. Run conduit and electrical wiring from building to the Liebert AC4.
2. Use copper wires only; proper wiring to use for power is 18-22 AWG stranded and shielded 

(18 AWG is recommended—see Table 4). Strip wires 1/2".

3. Secure the incoming electrical service wires to the Liebert AC4’s 24VAC input by sliding the wires 

into TB7, the 24VAC input terminal block. There is no polarity requirement when connecting to 

TB7. The ground wire must be connected to the earth ground terminal located on the side of the 

panel (see Figure 6).

Risk of electric shock. Can cause property damage, injury and death.
Check that power is removed from wires prior to installation. This unit should be installed 

only by properly trained and qualified personnel.

Risk of electric shock. Can cause property damage, injury and death.
The Liebert AC4 is designed for use on properly grounded (earthed) 24VAC power, 50Hz or 

60Hz. The ground wire for the power lead must be wired to the earth ground terminal (stud 

located next to the 24VAC terminal block).
This equipment is intended to be installed by a qualified and certified electrician who must 

review and approve customer supplied wiring and circuit breakers, verify correct input and 

grounded (earthed) connections to ensure compliance with technical standards and national 

and local electrical codes.

Risk of electric shock. Can cause property damage, injury and death.
Be sure that the Power On/Off switch is set to OFF before installing any wiring to this unit. 

The switch is in the top left corner of the unit, just below the battery pack.