Colin asks this question, which concerns whether there is a suitable RCD available to cope with inrush currents resulting from the internal switching inherent in variable speed drives that control electric motors. It has been answered by ABB (Theme – Distribution Equipment including Cable Management):
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Question: Do you have an RCD that can withstand the inrush leakage associated with switching in a 0.25kW variable speed drive (VSD)?
Answer: The selection of RCDs for the supply of VSDs depends upon several points – as follows:
Type of RCD - for single-phase VSD, it is only necessary to use an A-Type RCD, but for three-phase VSDs there is a need to use the B-Type because of the possibility of unidirectional earth faults caused by a failure within the drive electronics.
The sensitivity of the device needs to be based upon the protection requirements - for personnel shock risk, you will need 30mA type, but if this is not required, then 300mA is recommended to prevent unwanted tripping.
The current rating of the RCD will be based upon the full load current (FLC) of the motor.
ABB can offer A- or B- Types in either MCB or MCCB styles depending upon required current. For your wattage, the MCB style F200 series should be suitable.
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