What it is and what it does
The Siemens 5SV4445-0 is a 4-pole residual current operated circuit breaker (RCCB), Type AC, rated 125 A with a 100 mA trip sensitivity on a 400 V AC supply. Type AC means it detects sinusoidal AC residual currents only — standard for general-purpose circuits where no pulsed DC or smooth DC fault currents are present. The 100 mA sensitivity is a common choice for fire protection and equipment protection in industrial panels; it's less sensitive than the 30 mA required for personal shock protection, so it's typically used downstream of a 30 mA RCCB or on circuits where nuisance tripping from leakage is a concern. This RCCB sits in the Siemens 5SV4 family of RCCBs, designed for DIN-rail mounting in distribution boards and sub-distribution panels. The 4-pole configuration covers three-phase plus neutral, making it a fit for three-phase loads like motor starters, heating banks, or general power distribution where earth-fault protection is needed on all poles.
Lifecycle and compliance
The product class is B: return restricted — contact your Siemens partner for returns or warranty issues. This is a standard restriction for Siemens circuit protection products; it doesn't affect normal procurement.