Siemens 5SL3603-7 — 4-pole C-curve MCB for branch-circuit protection
The Siemens 5SL3603-7 is a SENTRON miniature circuit breaker with 4 poles (3P+N), a C tripping characteristic, and a 3 A rated current. It breaks fault currents up to 4.5 kA per EN 60898 at 400 V AC, making it suitable for final-circuit protection in residential and light commercial distribution boards where moderate inrush (motorized loads, fluorescent banks) is expected.
At 3 A, this is a low-current branch breaker, not a main or feeder device. The 4.5 kA breaking capacity is standard for domestic and light commercial panels per EN 60898; it is not rated for high-fault industrial mains. The 4-pole 3P+N configuration switches all three phases plus the neutral, which is required for TN-S or TT systems where neutral isolation is needed. Rated voltage 400 V AC covers three-phase line-to-line supplies common in European distribution. Terminals accept solid or stranded conductors from 0.75 to 25 mm², with a recommended tightening torque of 2.5 to 3 N·m. The 72 mm width occupies 4 width units on a DIN rail — standard for a 4-pole MCB. Ambient temperature range is -25 to +45 °C, with IP20 protection when conductors are connected, so it belongs inside a closed panel or enclosure.