What the ratings mean for fit
The 5SL6606-6BB: The 6 kA breaking capacity at 400 V is the maximum fault current this MCB can safely interrupt — sized for residential and light commercial panelboards where the prospective short-circuit current stays under that threshold. The B-curve (3–5× In magnetic trip) means it's suited for resistive or general-purpose loads with low inrush; not the right choice for motor circuits or transformers where a C or D curve would be needed to avoid nuisance tripping. The 3+N-pole configuration switches all three phases and switches the neutral, common in Italian and some European distribution boards where the neutral is switched alongside the phases.