where about in the on-site guide 17th or the regs book do you find the section on what breaker is used or cables, how much current cables can take?? and where to choose breakers for circuits? cheers
You start with you design current. From this you select the appropriate MCB, from the MCB rating you select a cable from appendix 4 iirc taking into account any correction factors. You then check the volt drop using the mV/A/m value given in appx 4 for the given cable type using the design current.
In a nustshell yes. However there are a few exceptions i.e. where you have cables in parallel or where the overcurrent protection is downstream and the MCB provides fault protection only.
The most common time you will see the latter is in a spur from a ring final circuit where the MCB is providing the fault protection but overcurrent protection is by the plugtop fuse in the spur.
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