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Unusual MCB

Sparkymania
Here's an interesting one.

Federal Electric 20A MCB. Had no type on it and was taking a long time to trip. Opened one up and discovered why it didn't have a type.

Others with it were ECC but virtually the same design. Only thermal. Both are plug in types called stab-lok and are bakerlite.


No instantaneous trip mechanism. Only a thermal one.



34200b5e07a12e120f5fc679b8b1b9aa-huge-mcb-with-no-instantanious-trip-mechanism-4.jpg
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    mapj1:

    Common on US made equipment like UPS and so on. looking at the arc trap, or lack of it, that may not have much of a rating for maximum breaking PSSC either - or it may be a 110V part and not really intended for mains.


    Was on a 3Ph DB. Due to the issue with the time it was taking to trip it was investigated and found to have no magnetic trip mechanism so the DB was changed. It was me who opened this one up to investigate.


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  • 0
    mapj1:

    Common on US made equipment like UPS and so on. looking at the arc trap, or lack of it, that may not have much of a rating for maximum breaking PSSC either - or it may be a 110V part and not really intended for mains.


    Was on a 3Ph DB. Due to the issue with the time it was taking to trip it was investigated and found to have no magnetic trip mechanism so the DB was changed. It was me who opened this one up to investigate.


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