What the ratings mean for fit
The 5SL6406-8CC: The D-curve (10–20× In magnetic trip) is sized for motor and transformer inrush currents — not for general lighting or resistive loads. At 6 A on a 4-pole 400 V system, this breaker protects a 3-phase load drawing roughly 4 kVA. The 6 kA breaking capacity at 400 V is sufficient for most commercial panelboards but should be verified against the available fault current at the installation point. The 4-pole configuration is standard for TN-S or TN-C-S systems where the neutral requires overcurrent protection. The D-curve holds through motor starting current.
Panel integration
Snap-on DIN rail mounting for standard 35 mm rail. The 4-pole width occupies 4 module spaces (roughly 72 mm). Spring-cage terminals accept 0.2–2.5 mm² solid or ferruled stranded conductors. Verify the available DIN rail length in your enclosure before committing the BOM line.