[Question] Sans Regulation for Circuit breakers

[JosiasLeRoux]

Good afternoon all

What does the SANS regulation states relating to using a bigger size breaker compared to a smaller size cable.

Thus, can you use a 25mm cable and connect it to a 250A Schneider CB, with a Micrologic trip unit, that can be turned down to protect the cable?

[GCE]

Hi

There was a previous thread on basically the same question - have pasted the reg that I thought cleared me and the thread link further down

5.4.3 Current
The equipment shall be suitable for operation at the maximum steady
(r.m.s.) current to which it is likely to be subjected. It shall also be able to
carry the current that is likely to flow under abnormal conditions and for the
period that the current is likely to flow.
NOTE The period that an abnormal current will flow is equal to the operating time of
any protective device

6.7.2.4 Protective devices that have adjustable overload settings shall only
be used if the means of adjustment is not accessible without the use of a
tool and the adjustment can only be made by means of a tool.

https://www.theforumsa.co.za/forums/showthread.php/24087-Settable-C-Breaker