Siemens 3UL2201-2A Residual Current Device RCCB

Siemens 3UL2201-2A is a residual-current device component — a summation current transformer (SCT) designed for use with Siemens RCCB assemblies. It provides a 0.5 A secondary, feeding the residual-current protection circuit so the RCCB trips when leakage currents cause an imbalance among the conductors. As a specialized SCT option within Siemens’ residual current protection ecosystem, the 3UL2201-2A enables accurate monitoring of current in multi-conductor paths to ensure rapid isolation of the protected circuit in the event of earth leakage. Typical applications include low-voltage electrical installations in residential, commercial, and light-industrial settings where Siemens SENTRON protection devices are deployed and integration with RCCB modules is required. The part number 3UL2201-2A uniquely identifies this SCT component for residual current monitoring, reinforcing its role as a critical accessory that supports reliable leakage protection in Siemens RCCB configurations.