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Type B time delayed rcd

Baldyhugh
Hi


As part of a job I’m currently on I have connected a single phase supply to a Danfoss variable speed inverter drive. I wasn’t aware that this would be part of the job but there you go. Anyway I connected it and powered it up and a few seconds later it tripped the rcd. I informed the installers of the drive incase it was faulty but they said that it’s probably the wrong type of rcd. I researched the spec of the drive which says that I need a type B time delayed rcd. I spoke to Hager technical dept as these are the boards I have used and they said that they only do a 4 pole B type but not time delayed. There is an A type time delayed available which is double pole but they didn’t think that it would work as it doesn’t monitor dc which the B type does. These different types are new to me so would anyone have experience of them to offer some advice?


Thanks
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  • 0
    A B-type should trip on everything an A type should trip on - plus it'll also trip on pure d.c. leakage.


    Likewise a A type should trip on everything an AC type should trip on - plus pulsing d.c.


    So changing to a B-type of itself isn't likely to solve an 'unwanted tripping' situation.


    Changing from a non-delayed to delayed might help - in that the equipment might be producing short bursts of leakage beyond normal limits - which a time delayed unit might ignore, but an instantaneous one respond to.


       - Andy.
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  • 0
    A B-type should trip on everything an A type should trip on - plus it'll also trip on pure d.c. leakage.


    Likewise a A type should trip on everything an AC type should trip on - plus pulsing d.c.


    So changing to a B-type of itself isn't likely to solve an 'unwanted tripping' situation.


    Changing from a non-delayed to delayed might help - in that the equipment might be producing short bursts of leakage beyond normal limits - which a time delayed unit might ignore, but an instantaneous one respond to.


       - Andy.
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