ABB KXTFYUC4 is an undervoltage release (UVR) accessory for SACE Tmax XT circuit breakers, designed for XT5 and XT6 frame units. When supply voltage falls outside its setpoint, the UVR releases the breaker to prevent re-energization, supporting safe restart in automation control systems. Rated for 110–127 V AC (50/60 Hz), the KXTFYUC4 is intended for use with Tmax XT series breakers. Its ABB part designation is KXTFYUC4 within the XT product family.
