Nuvation Energy Bms: Best Practices; Grounding - Nuvation Energy High-Voltage BMS Installation Manual

Nuvation Energy High-Voltage BMS - Installation Guide

6. Nuvation Energy BMS: Best Practices

This section describes important concepts which need special attention to achieve a reliable
installation.

6.1. Grounding

It is assumed that Nuvation Energy BMS will be attached electrically to an earth or local chassis
ground point, via the DIN rail grounding provision (#8-32 , ¼" Hex-head drive, earth grounding
screw), and the mounting brackets on Nuvation Energy BMS component enclosures.
Voltages and signals on the Stack Bus and Link Bus cables are chassis/earth ground referenced. In
addition, the Stack Controller module's USB port, non-isolated RS485, and GPIO-In signals; and the
Power Interface module's Contactor coils and Interlock signals are chassis/earth ground referenced.
All connections to the battery stack are isolated from chassis ground. This includes the Current Shunt,
Thermistor, and Stack Power connections on the Power Interface; and the Battery Cells and
Temperature Sensors connections on the Cell Interface, and Ethernet and CAN interfaces on the Stack
Controller.
It is acceptable, as may be required in some cases, for the battery stack to be ground-referenced at
some single point. However, a 24 V RMS AC or 24 V DC power supply connected to the Power
Interface module's External Power connection must be isolated from earth/chassis ground, with a
working isolation voltage of at least 60 V RMS for all Power Interface models.
Protective earthing conductors must be attached to each DIN enclosure at the designated ground
screw location on the DIN clip. Furthermore, the DIN rail itself should be connected to earth ground.
14 AWG wire with a jacket color appropriate for indicating it is a protective earthing conductor must
be used.
An example of this grounding scheme is shown below:
Figure 15. Example Earth Ground Wiring Diagram
Document ID: NE-IG-001 37 Rev 2.1, 2020-03-13