Engineering notes
MCB or MCCB: a house breaker is not an incoming
MCBs belong on small branches. Incomers and large feeds need an MCCB with the drawn Icu.
The schedule says “125 A 3P breaker”. Stores issue a domestic MCB. After a transformer the fault level is tens of kA — the MCB’s breaking capacity is short. Welded contacts on a short are a materials choice, not bad luck.
MCBs for lighting, sockets, one FCU. MCCBs for incomers and large branches where the file states Icu. Same 125 A, two families. Add voltage, poles, curve (C or D), and Icu from the drawing.
Send the single-line. We will not swap an MCCB for an MCB to save money. Electrical materials