The next series of inverter-chargers is equipped with a programmable earthing relay able to bond the neutral wire (on load side) to the earth (case of the device). This relay can be configured in the following mode:
Offgrid self-managed (default): With “Offgrid self-managed” selected the system will handle the connection and disconnection of the earthing relay depending on the inverter working mode: Offgrid or Ongrid. This mode can only be selected in a discontinuous neutral wiringconfiguration. Between each Ongrid-Offgrid transition a relay inspection is realized and the grounding path is validated to ensure system safety.
Typical installations where “Offgrid self-managed” should be selected are:
- Mobile installations.
- Installations connected to grid/genset via a plug connector.
- Standard stationary installations.
With this mode a permanent check of the neutral voltage is performed. RCD breakers should
be placed on the load side.
Solid neutral: This configuration is used when continuous neutral is required. In this case the system will never close the earthing relay since the Neutral to earth bonding should exist downstream. Grounding path is monitored to ensure system safety. An error is raised if grounding is not correct or if neutral continuity is not correct.
Typical installations where “Solid neutral” should be selected are stationary installations where local rules specify explicitly continuous neutral wiring.
Disabled: Disabled mode keeps earthing relay opened and no earthing path verification is realized. This mode should be used with precaution since user must ensure installation safety in any case. Typical installations where “Disabled” should be selected are installations with IT earthing system. In an IT network there is no grounding connection and safety isolation is ensured by an external impedance check device.