I have a 3 section 3 phase MCB rated at 25A. Is this 25A total or 25A on each phase?
TIA.
3 Phase MCB
Mar 30, 2008
7 Replies
Consult the manufacturer's specification for the product.
Never take any "advice" with safety implications off a usenet group - especially this one.
Oops, I have just given some advice with safety implications....
-- Sue
UK by the way
It's almost certainly 25A each phase. I've never seen it rated any other way.
Thanks James.
| I have a 3 section 3 phase MCB rated at 25A. | Is this 25A total or 25A on each phase?
Some models have 1, 2, and 3 pole variations. The 3 pole ones can still be used on 3 separate single phase circuits. So that would seem to imply that it's the specified amperage for each phase, sensed individually (so one of them going over-current would trip them all together ... not the sum of currents exceeding some rating or sum of ratings).
Each. Draw 25+ amps on any phase = trip
RE
As James wrote, it is almost certainly a rating per contact pair. I've never encountered one that hasn't been.
But if I was in any doubt, I'd turn to the manufacturer's data sheet.
Three phase at ~25A could cause a great deal of damage.
-- Sue
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