Residual-current monitoring unit (RCMU)

The product is equipped with an all-pole sensitive residual-current monitoring unit in accordance with IEC/EN 62109-2 and VDE 0126-1-1. The all-pole sensitive residual-current monitoring unit monitors AC and DC residual currents and redundantly disconnects the product from the utility grid if residual current jumps of > 30 mA occur. If the residual-current monitoring unit malfunctions, all poles of the product are immediately disconnected from the utility grid. If the protection provided by automatic disconnection of the power supply in accordance with DIN VDE 0100-410 is fulfilled by an appropriate overcurrent protective device, the product does not require an external residual-current device to operate safely. If local regulations require the use of a residual-current device, the following must be observed:

• The product is compatible with type B residual-current devices. The rated residual current of the residual-current device must be 500 mA or higher (for information on selecting a residual-current device, see Technical Information "Criteria for Selecting a Residual-Current Device" under www.SMA-Solar.com). Each inverter in the system must be connected to the utility grid via a separate residual-current device.

• When using residual-current device with a lower rated residual current, there is a risk of false tripping of the residual-current device, depending on the system design.