The Siemens 5SL6204-7 is a SENTRON miniature circuit breaker, 2-pole, C-curve, rated 4 A with a 6 kA breaking capacity per both EN 60898 and IEC 60947-2. It's designed for residential and infrastructure branch-circuit protection on 400 V AC systems at 50/60 Hz.
If your panel's prospective short-circuit current exceeds 6 kA, step up to a 10 kA rated unit like the 5SL4363-7. The 2-pole design (2 MW) switches both phase conductors simultaneously, making it suitable for single-phase 230 V or two-phase 400 V circuits. DC rating maxes out at 72 V — not a primary DC breaker, but usable on low-voltage DC control circuits within that limit. Power loss per pole at rated current in hot state is 0.7 W, so total dissipation for the 2-pole unit is 1.4 W; negligible for thermal management in a standard enclosure.
Mounting position is any orientation — no derating needed for horizontal or inverted mounting. Sealable (can be locked in OFF position with a padlock), halogen-free and silicon-free — important for clean-room or corrosive-environment installations where outgassing matters. Pollution degree 2, overvoltage category III, energy limitation class 3.