Pole configuration and voltage
This is a 4-pole (3P+N) design — three protected phases plus a switched neutral that opens and closes with the phases. The neutral pole is not internally protected but is mechanically linked, so you get full isolation on all four poles when you switch off. That matters for a 3-phase distribution board where you need to guarantee the neutral is disconnected for safe downstream work.
The 5SL6610-6 occupies 4 modular width units (72 mm wide) on a DIN rail, with a depth of 76 mm and a height of 90 mm. It mounts in any position and requires 70 mm of installation depth behind the panel. Sealable, halogen-free, and silicon-free construction means it's suitable for environments where outgassing or contamination is a concern, like clean rooms or food processing areas.
Supplementary devices and power loss
That's modest, but in a densely packed enclosure with multiple breakers, it adds up — account for it in your thermal budget.