Vertiv Liebert MC, Installer/User Manual

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2.4.3 Surge Protective Device
An optional Surge Protective Device (SPD) can be field-wired to protect the condenser from power surges
that threaten sensitive equipment. The condenser’s electrical panel provides a terminal block to allow the
SPD to be wired in parallel with the high-voltage power. An additional low-voltage terminal block is
provided on condensers to allow monitoring of the SPD alarm circuit.
ASCO Series 420 surge-protective device provides 50 kA per mode of surge current protection. An
illuminated green LED indicates the SPD is On and operating properly. An illuminated red LED indicates
that the device may require replacement.
When both LEDs are Off, there is no power to the condenser, either from a power failure or because the
condenser disconnect is in the Off position.
Vertiv | Liebert® MCV™ Installer/User Guide | 10