Liebert NX UPS System Protection, Battery Ground Fault Detection, Terminal Name Definition

Options—For Assembly Inside the UPS Cabinet

8.0OPTIONS—FOR ASSEMBLY INSIDE THE UPS CABINET

Several items of optional equipment are available for connection to the Liebert NX UPS. These are described in this section of the manual and should be fitted prior to installation.

8.1Protection

8.1.1Battery Ground Fault Detection

In addition to any residual current device mounted externally and upstream the UPS or when optional isolation transformers are fitted to the UPS, an optional residual battery current device can be fitted to detect leakage current from the battery into the PE (Protective Earth) Residual current range monitored: 30~3000mA.

Power supply voltage for the set: AC230V (L-N);

When a battery ground fault is detected, an alarm will appear on the UPS display panel. An additional Dry contact fault Alarm signal is available for remote monitoring:

Table 24 Dry contact fault alarm signal is available for remote monitoring

Terminal	Name	Definition
21	Common	Battery Ground Fault Detection – can be
		programmed as Alarm or Pre-Alarm
22	NC
24	NO

The Battery ground fault detection set contains one CT (current transformer) and one DC sensitive residual current monitor. The connection of this set for UPS is illustrated as follows.

Figure 36 Battery ground fault detection set connections

Battery

Batt +

Batt-N

Batt -

Current Transformer

W1-A358 (installedBCB or externally only)

Contactor

X

X

Socket	Output
	Phase
	Output
	Neutral

K1 K2 I2 I2

A111

A214

Battery Ground Fault Detection Resys B470 (AC230)

	Monitor Board
	-U2
4	+12V
2	IN DRY-X3
BtG
	UPS

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