Use of Type B MRCDR with no Neutral

We have Type B MRCDR's installed within our MDU/MDA assemblies. The manufacturer/model is Doepke - ELR-3BN+ residual current transformer.

They have been installed on supplies to VFD controlled equipment so we have followed manufacturers guidance.

My question is this.....The VFD equipment does not require a Neutral therefore only the 3 phases pass through the associated residual current transformer. 

We were able to test the device as both a Type AC and a Type A and the device operates, it does not however operate as type B when this is selected on the MFT.

I may be worried about nothing as they are operational.

Please share your thoughts

Parents
  • RCD testers are designed and manufactured to BS EN 61557-6 Effectiveness of residual current devices (RCD) in TT, TN and IT systems for testing electrical installations. The standard requires that the instrument be able to verify correct disconnection of the supply in the event of a fault but it does not provide requirements for extensive product standard testing.  Subsequently, not all instruments will be well suited to carrying out anything more than the most rudimentary of tests. 

    electrical.theiet.org/.../

Reply
  • RCD testers are designed and manufactured to BS EN 61557-6 Effectiveness of residual current devices (RCD) in TT, TN and IT systems for testing electrical installations. The standard requires that the instrument be able to verify correct disconnection of the supply in the event of a fault but it does not provide requirements for extensive product standard testing.  Subsequently, not all instruments will be well suited to carrying out anything more than the most rudimentary of tests. 

    electrical.theiet.org/.../

Children
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