Grounding and GND/iGND connections

GND terminals

Non-isolated interfaces share their reference with the power supply. Interconnect device GND terminals even when using separate power supplies. Use a single-point connection to protective earth PE; bond a metal enclosure to PE as well.

iGND terminals

iGND is the reference for an isolated circuit, intended to connect equipment in another electrical installation with its own PE system. Where that isolation is not required, connect iGND to the PE bar. Do not interconnect isolated grounds simply for convenience: a large network of low-current input wiring can act as an antenna for interference.

One electrical installation

For one cabinet and sensors within the same equipotential zone, join GND and iGND to the common cabinet earth bar. Connect the iGND network to other grounds and the cabinet earth at one point only.

Signals from a separate installation

If external equipment has its own earth bar and equipotential bonding system separate from the Wiren Board cabinet, connect iGND to that equipment's GND. Do not also connect it to the Wiren Board cabinet earth bar.

RS-485 between separate installations

Use a galvanically isolated interface such as WBE2-I-RS485-ISO between cabinets in separate buildings with different grounding systems. Bond the cable shield to one cabinet earth bar.