The Siemens 5SY4515-8CV is a miniature circuit breaker (MCB) with a D1.6 tripping characteristic, rated for a 1.6 A load on a single-pole-plus-neutral (1P+N) configuration.
The 1.6 A rating sets the continuous current the breaker carries without tripping; the D curve allows a magnetic trip threshold of 10 to 20 times rated current (16 to 32 A instantaneous), so it holds through the inrush and clears only on a hard fault. The 15 kA Icu at both 230 V and 400 V covers the most common industrial supply voltages, and the 1P+N form factor fits standard DIN-rail distribution boards, switching the line conductor only while the neutral passes through unswitched.