External current transformer installed at the transformer neutral-to-ground bonding conductor (star-point grounding) to measure ground return current (G_ret) during earth faults. The 250 A rating suits higher-power transformer installations. The secondary signal connects to the ETU660 LSIG trip unit in Siemens 3WL10 air circuit breakers and 3VA27 moulded case circuit breakers, enabling ground-fault return protection.

Key Features

• 250 A primary rated current for ground return measurement at transformer neutral
• Designed for ETU660 LSIG trip units with G_ret protection function
• Compatible with 3WL10 (up to 1250 A) and 3VA27 (up to 1600 A) circuit breakers
• Heavier 2.4 kg core for higher current handling without saturation
• Ambient temperature range: -25 °C to +70 °C
• RoHS compliant, made in Italy

Technical Specifications