Siemens SENTRON 5SN6340-7CN — 40 A, C-Curve, 3-Pole MCB
The 3-pole design (3P) switches all phases simultaneously, with no switched neutral (neutral conductor switching: No). Frequency range covers 50/60 Hz, so it is equally at home on 50 Hz European or 60 Hz North American supply systems (within the voltage rating).
At 54 mm wide (3 modular width units), this breaker occupies three standard 18 mm DIN-rail slots. Terminals accept solid conductors up to 25 mm², which is generous for a 40 A device — you can land the full-rated feeder without pigtailing or doubling up. Pollution degree 2 (non-conductive pollution only) is the standard for normal factory-floor environments.
The overvoltage category is III (fixed installation), and the energy limitation class is 3, meaning it limits let-through energy to a level that protects downstream equipment during a fault. The sealable design (tamper-evident seal available) is useful for utility or metering applications where unauthorized switching must be prevented.
