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Type-A RCD failing 180 degree ramp test

Former Community Member
Former Community Member
Hi


We are testing a type-A RCD (see image: "ABB") with a METREL MI 3152 (see image: "MI 3152 test").

As the image shows, the ramp test (I delta) is failing to trip the RCD for the negative half wave.


Have oneone seen this before?


Br Sebastian
attachments.zip
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  • Former Community Member
    0 Former Community Member

    mapj1:

    yes that is a "ramp test" to the older hands among us.


    If you can please re-test, lying to the meter that it is an AC type, and also verify that all phase to phase voltages are similar.

    how is the meter connected - how are you choosing the phases to test - your diagram may imply live no1 and earth ,

    does it work if you shuffle them  and use say L3 and earth ?


    Is this the only RCD of its type you have tested with this meter, or has another one tested OK?


    What is the NE voltage, and where is the NE bond ?


     




    A new test has to be coordinated and will take some time to be done, unfortunately.


    The test was only done between phase 1 and earth (PE) as shown on "RCD_schema plus neutral.PNG". Also see figure 7.27 on page 105 in the METREL manual for the setup (see :"connection diagram.PNG").


    There is no NE bond on the primary side of the "T1" transformer as this is done on the supplier side (I assume (this could be a mistake))

    The NE voltage on the primary side was measured to be 0.1 Vdc and 0.5Vrms


    We have tested other RCDs of this type that have passed, but it seems to only be related to this specific installation type. 

    attachments.zip
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  • Former Community Member
    0 Former Community Member

    mapj1:

    yes that is a "ramp test" to the older hands among us.


    If you can please re-test, lying to the meter that it is an AC type, and also verify that all phase to phase voltages are similar.

    how is the meter connected - how are you choosing the phases to test - your diagram may imply live no1 and earth ,

    does it work if you shuffle them  and use say L3 and earth ?


    Is this the only RCD of its type you have tested with this meter, or has another one tested OK?


    What is the NE voltage, and where is the NE bond ?


     




    A new test has to be coordinated and will take some time to be done, unfortunately.


    The test was only done between phase 1 and earth (PE) as shown on "RCD_schema plus neutral.PNG". Also see figure 7.27 on page 105 in the METREL manual for the setup (see :"connection diagram.PNG").


    There is no NE bond on the primary side of the "T1" transformer as this is done on the supplier side (I assume (this could be a mistake))

    The NE voltage on the primary side was measured to be 0.1 Vdc and 0.5Vrms


    We have tested other RCDs of this type that have passed, but it seems to only be related to this specific installation type. 

    attachments.zip
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