The Siemens 5SJ6114-7 is a SENTRON 5SJ6 miniature circuit breaker rated at 0.3 A with a C tripping characteristic, designed to protect a single pole at 240 V AC and up to 60 V DC.
The 0.3 A C-curve is the headline decision point here. At 0.3 A it's a very low-current branch; verify your load's full-load amps don't exceed 0.24 A continuous (80% rule for continuous loading per NEC if applied). The mechanical service life of 20 000 switching cycles is typical for an MCB — not a cycling device, but it will handle routine on/off for maintenance without issue.