Vertiv Liebert EXS - Page 9

WARNING! Backfeeding protection
This UPS is fitted with a dry contact closure signal for use with an external automatic disconnect device
(supplied independently) to protect against backfeeding voltage into the incoming terminal through the
rectifier or bypass static switch circuit. The airgap of the disconnect device should be minimum 1.6 mm. A
label must be added to all external incoming primary supply disconnect device to warn service personnel that
the circuit is connected to a UPS. The text of the label has the meaning: Risk of voltage backfeed! Isolate the
UPS, then check for hazardous voltage between all terminals including the protective earth before working
on this circuit.
User serviceable components (for service personnel)
• All equipment maintenance and servicing procedures involving internal access requires the use of a tool and
should be carried out only by trained personnel. There are no user serviceable parts behind covers requiring a
tool/key for removal.
• The UPS meets the safety requirements completely in operator access area. Only service personnel can contact
the hazardous voltage inside the UPS. However, the risk of contacting these voltages is minimized because the
components with hazardous voltage have protective covers, which must be removed/installed using proper
safety tools. No risk will exist if you follow the general norms and in accordance with the procedures
recommended in this manual on equipment operation.
Battery voltage exceeds 240 VDC (for service personnel)
• All physical battery maintenance and servicing procedures requires the use of a tool and should be carried out
only by trained personnel.
• Operation on the battery can result in electric shock and high short-circuit current, therefore, before operating
the battery, the following precautions should be observed:
• Remove the watches, rings, and other metal objects.
• Use the tools with insulation handle.
• Wear rubber gloves and shoes.
• Try not to place the tools and metal objects on the battery surface.
• Cut off the charge power supply before connecting or disconnecting the battery terminals.
• Check whether the battery is earthed accidently, if yes, disconnect the earthing. Contacting with earth
battery parts will result in electric shock. Therefore, make sure that the battery is not earthed during
installation and maintenance.
• Battery manufacturers provide the details of the precautions to be observed when working on, or in the vicinity of
the batteries. These precautions should be followed implicitly at all times. Attention should be paid to the
recommendations concerning local environmental conditions and the provision of protective clothing, first aid,
and fire fighting facilities.
• If the flame retardancy rating of the battery case is HB, the UPS is not intended for computer room.
WARNING! When selecting the UPS system upstream distribution protection equipment, ensure that it
complies with the local electric regulations. The specified upstream breakers are required to obtain the
conditional short circuit current rating, Icc at 30 kA symmetrical rms. The specified upstream breakers
should comply with a UL248 series standard.
1 Important Safety Instructions Proprietary and Confidential ©2023 Vertiv Group Corp. 3
Vertiv™ Liebert® EXS Installer/User Guide