Configuring Your Neutral and Ground Connections

6.5Grounding Configuration, Corner-Grounded Delta or Impedance-Grounded Wye

As previously mentioned, Series 610 SCC requires a bypass input neutral for sensing and monitoring. With a wye-connected input source, the installer should always connect the building service neutral to the System Control Cabinet (SCC) output neutral to achieve this. When the building service is delta- connected, however, the installer must take special steps to ensure reliable UPS functioning.

If the building service is corner-grounded delta or impedance-grounded wye, the UPS requires the Series 610 Isolated Neutral Kit, as do each of the UPS modules. This kit uses control isolation trans- formers to create a reference point. For this application, the SCC output neutral must not be bonded to the SCC ground.

Figure 8 Preferred grounding configuration, corner-grounded delta or impedance-grounded wye

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Emerson 610 installation manual Configuring Your Neutral and Ground Connections