The Siemens 3UL2303-1A is a residual current transformer designed for use in residual current monitoring systems, specifically for fire protection applications. It features a compact design with an opening of 55 mm, suitable for routing cables through the transformer. The device operates with a rated residual current of 30 mA and a rated current up to 40 A, making it appropriate for monitoring leakage currents in electrical installations. Housed in a white enclosure, this transformer is part of the Siemens 3UL series and complies with relevant safety standards for residual current monitoring. It is intended for permanent installation in distribution boards or similar enclosures. The product is manufactured by Siemens, a trusted brand in electrical engineering, ensuring reliable performance and long service life. Key specifications include a rated frequency of 50/60 Hz and an insulation class suitable for industrial environments. This component is ideal for integration into fire protection systems to detect ground faults and prevent fire hazards. The transformer is easy to install and connect, with clear terminal markings for wiring. It supports monitoring of single-phase or three-phase circuits, providing versatility for various applications. The compact dimensions allow for space-saving installation, while the robust construction ensures durability under normal operating conditions.