125 A, 500 mA, 4-pole type AC RCCB
The Siemens 5SV4745-0 is a 4-pole residual current operated circuit breaker (RCCB), type AC, rated at 125 A with a 500 mA trip sensitivity at 400 VAC. This is a high-current RCCB for main incoming protection or sub-distribution feeders where earth leakage detection is required. The 500 mA rating means it's sized for equipment protection or fire-prevention leakage monitoring, not personnel shock protection — that's the domain of 30 mA devices. Note the manufacturer's restriction: use of this device is not permitted in all countries; national installation regulations must be observed.
Packaged as a single unit with dimensions 78 x 97 x 85 mm. As a 4-pole RCCB, it occupies four modular-width DIN-rail spaces in a standard distribution board. The 125 A rating requires incoming cable sized accordingly — typically 35 mm² copper for the line and neutral conductors. The 500 mA sensitivity avoids nuisance tripping on circuits with natural leakage from long cable runs or equipment filters.