What this 4-pole D-curve MCB does on the line
The Siemens SENTRON 5SL4406-8 is a 4-pole (4P) miniature circuit breaker with a D tripping characteristic, rated 6 A at 400 V AC. Rated current derates with ambient temperature: 6 A at 30 °C drops to 5.76 A at 40 °C and 5.37 A at 55 °C, so if the panel runs hot — say next to a drive cabinet or in a sealed enclosure — factor that derating into your load calculation. The breaker is sealable (tamper-proof tag possible) and carries touch protection on the terminals, which matters for IP20 panels where live parts stay exposed only when the cover is off.
The 4-pole design switches all three phases plus the neutral (no neutral conductor switching function on this variant — the neutral is switched through the breaker).
Environmental and compliance range
Halogen-free and silicon-free construction, so it's suitable for clean environments where outgassing matters (data centers, medical, food processing). The breaker is classified under IEC 81346-2 and DIN EN 61346-2 as function code F (protective device).