Three Phase Circuit Breakers

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Can three single phase circuit breakers[one on each phase of course]be used rather than a three phase breaker?
 
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Its possible to argue that you could if you really wanted, since thats effectivly what you get with a cirucits thats protected with fuses rather than MCBS, however its as rough as **** just to avoid buying the correct mcb!
 
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Yes, of course you can. It's specifically allowed by BS7671, 431.1.1

If the circuit feeds a motor, operation of a single MCB would result in single phasing. This could lead to thermal overload and the failure of the motor.

Single phasing should not happen because all three phase motors should have single phasing protection.
 
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