ABB SPAJ 140C Combined OC and Earth Fault Relay

The ABB SPAJ 140C is a combined overcurrent and earth-fault protection relay for medium-voltage feeders, motors, and transformers, providing four-step protection with independent time delay settings for phase overcurrent and earth fault elements. It is part of ABB's proven SPAJ relay family that has been installed in hundreds of thousands of distribution and industrial switchgear panels worldwide since the 1980s, and its robust static analog design has established a reputation for extreme reliability in harsh tropical and desert environments. The relay provides two-step phase overcurrent protection (I> definite-time overcurrent; I>> instantaneous overcurrent) and two-step earth fault protection (Io> delayed earth fault; Io>> instantaneous earth fault), with individual time multiplier settings and current thresholds for each element adjusted via calibrated front-panel rotary switches — a simple, direct adjustment method that does not require a laptop or parameterisation software.

The SPAJ 140C uses independent IDMT (Inverse Definite Minimum Time) or definite time characteristics for the I> and Io> elements, selectable by jumper. IDMT characteristics available include IEC Standard Inverse (SI), Very Inverse (VI), and Extremely Inverse (EI) per IEC 60255-151, providing grading flexibility for coordination with both upstream power fuses and downstream circuit breaker protection. The two output relays trip the associated circuit breaker via the MV switchgear trip coil, and the integral mechanical flag indicator clearly shows which protection element — I>, I>>, Io>, or Io>> — operated to cause the trip, enabling rapid fault classification by maintenance engineers without SCADA access.

The SPAJ 140C remains the most widely installed protection relay in Saudi Arabia's legacy 13.8 kV and 33 kV distribution network due to its original specification by SEC in the 1990s and 2000s. Thousands of units remain installed in both SEC public distribution substations and in industrial switchgear at ARAMCO, SABIC, MARAFIQ, SWCC, and large private sector facilities across the Kingdom. Genuine ABB replacement SPAJ 140C relays are required when existing relays fail or when secondary injection testing reveals calibration drift beyond acceptable limits. Razz Middle East maintains SPAJ 140C relays sourced to order as genuine ABB products for direct replacement, and supplies the relay for new switchgear panels specified with SPAJ 140C for compatibility with existing installed base.

Razz Middle East provides SPAJ 140C relays with secondary injection test reports confirming calibration of all protection elements, and can provide legacy relay settings translation for sites replacing failed relays and requiring settings to be reproduced from the original protection coordination study.