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25A slow blow circuit breaker?

Farmboy

What is a 25A slow blow circuit breaker? It's to supply an Xray machine in a dental practice. The data sheet states it draws 12A, and a 13A switch fuse has been asked for as the point of connection, along with this 25A type B slow blow CB at the supply end, but I've never heard of it - wouldn't surprise me if they meant fuse not CB.

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  • 0

    I'm replying to myself to bump my question up the list - it had been blocked due to some of the words contained therein being in the moderators banned list but has now been resolved - thanks Lisa!

    So, what is this slow blow CB?

    F 

  • 0 in reply to Farmboy

    I suspect that they mean a type C MCB as these are relatively slow acting if compared to the more common type B items. Not that common in a 25 amp rating.

    As protection is also provided by a 13 amp fuse, then in my view the 25 A MCB should be regarded as a MINIMUM, and not as a requirement. 32 amps would in my view be fine, with cable to suit.

    I suspect that the equipment has a significant inrush current, that a 13 amp fuse should withstand, but that might trip a standard type of circuit breaker of 20 amps or less. Hence the requirement for a minimum of 25 amps.

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  • 0 in reply to Farmboy

    I suspect that they mean a type C MCB as these are relatively slow acting if compared to the more common type B items. Not that common in a 25 amp rating.

    As protection is also provided by a 13 amp fuse, then in my view the 25 A MCB should be regarded as a MINIMUM, and not as a requirement. 32 amps would in my view be fine, with cable to suit.

    I suspect that the equipment has a significant inrush current, that a 13 amp fuse should withstand, but that might trip a standard type of circuit breaker of 20 amps or less. Hence the requirement for a minimum of 25 amps.

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