ABB SPAJ140C Retrofit-Ready Protection Relay for REJ/SPAJ

ABB SPAJ140C Retrofit-Ready Protection Relay for REJ/SPAJ Control Systems

The ABB SPAJ140C is a combined overcurrent and earth-fault protection relay engineered for seamless retrofit into existing REJ and SPAJ series protection schemes. Whether you are modernizing an aging substation panel, replacing a discontinued relay in a medium-voltage switchgear cabinet, or restoring protection coverage after an unexpected failure, the SPAJ140C delivers the electrical compatibility and functional equivalence that retrofit engineers demand. Its compact DIN-rail and flush-panel mounting options allow direct installation into existing cutouts without structural modification, dramatically reducing downtime during planned or emergency replacement campaigns.

For facilities running legacy ABB SPAJ110C, SPAJ131C, or SPAJ141C relays, the SPAJ140C represents the most straightforward upgrade path. The relay maintains the same terminal block layout and auxiliary power supply input range (typically 24–250 V DC/AC), which means existing wiring harnesses, CT secondary circuits, and trip output cabling can be reused without re-termination. Before installation, engineers should verify the CT ratio, the IDMT characteristic curve selection (Normal Inverse, Very Inverse, or Extremely Inverse), and the high-set instantaneous pickup settings to ensure the new relay mirrors the protection philosophy of the outgoing unit.

Upgrade Compatibility Table

Retrofit Planning for Existing Automation Systems

A successful SPAJ140C retrofit begins well before the relay arrives on site. The first step is a thorough audit of the existing protection panel. Engineers should document the current SPAJ131C or SPAJ110C settings — including overcurrent pickup (I>), time multiplier setting (TMS), high-set pickup (I>>), and earth-fault thresholds (Io>, Io>>) — so these can be replicated exactly on the SPAJ140C during commissioning. The ABB CAP505 or CAP531 relay setting tool can be used to upload and verify parameter files before the relay is energized.

On the hardware side, the SPAJ140C shares the same 24-terminal rear connector standard as the broader SPAJ family, which means the existing wiring from the ABB SACO 16D2 or SACO 24D4 output relay modules can typically be reused. If the panel also houses an ABB REM543 or REM545 feeder protection terminal, the SPA-bus communication chain must be re-addressed after the relay swap to avoid node conflicts on the RS-485 loop. A short-circuit test on the SPA-bus segment using the ABB SPA-ZC 17 or SPA-ZC 22 converter will confirm communication integrity before the panel is returned to service.

For panels that include an ABB SPAM150C or SPAM150D motor protection relay in the same cubicle, the earth-fault CT secondary circuit must be carefully isolated during the SPAJ140C installation to prevent spurious trips on adjacent feeders. Similarly, if the protection scheme relies on an ABB SPTU relay for trip circuit supervision, the trip output wiring from the SPAJ140C should be verified against the SPTU input voltage threshold before closing the circuit breaker. Panels equipped with ABB REF615 or REF630 feeder protection IEDs may offer a direct IEC 61850 GOOSE-based replacement path, but for sites where SPA-bus infrastructure is already in place, the SPAJ140C retrofit is the faster and more cost-effective solution.

Where the existing panel uses an ABB SPTO 1D3 or SPTO 1D5 trip output module, the SPAJ140C’s binary output contacts (normally open, normally closed) are fully compatible with the existing trip coil wiring. Confirm the trip coil voltage and current rating against the SPAJ140C output relay specification (typically 250 V DC, 5 A continuous) before energizing. If the panel also includes an ABB SPCU 1C1 or SPCU 3C1 control unit for local/remote switching, the SPAJ140C’s binary input terminals can be wired to the control unit’s output contacts to preserve existing interlock logic without PLC reprogramming.

Downtime Control During System Migration

Minimizing unplanned downtime is the primary concern for any protection relay retrofit. The SPAJ140C’s wide auxiliary supply range eliminates the need for a separate power supply module swap, which is one of the most common sources of delay in legacy relay replacements. Because the relay accepts both DC and AC auxiliary power within the same input range, it can be energized and tested on the bench using the existing panel supply voltage before the old relay is removed from service.

A recommended practice is to pre-configure the SPAJ140C off-line using the ABB CAP505 setting tool, loading all protection parameters from the documented settings of the outgoing relay. This allows the on-site swap to be completed in a single planned outage window — typically 30 to 90 minutes for a single feeder — rather than requiring multiple visits for setting verification. Once the relay is installed and wired, a secondary injection test using a portable relay test set (such as the Omicron CMC 356 or equivalent) should be performed to verify pickup accuracy and trip timing before the feeder is re-energized.

For sites where continuous production cannot tolerate even a brief outage, a temporary bypass scheme using a portable protection relay can be deployed on the feeder while the SPAJ140C is installed and commissioned. After commissioning, the bypass is removed and the SPAJ140C assumes full protection responsibility. This approach is particularly effective in water treatment plants, continuous chemical processes, and mining conveyor systems where feeder protection must remain active at all times.

All SPAJ140C units supplied by SMARTNEXMSK are pre-tested prior to shipment. Each unit undergoes a full functional verification covering pickup accuracy, IDMT timing curves, output relay operation, and SPA-bus communication port integrity. Units are shipped with original or equivalent documentation and are backed by a 12-month warranty covering manufacturing defects and functional failure under normal operating conditions. Stock is maintained for fast dispatch to support both planned retrofit projects and emergency replacement requirements.

Retrofit Support FAQ

Q1: Is the SPAJ140C a direct drop-in replacement for the SPAJ131C and SPAJ110C?
Yes. The SPAJ140C shares the same rear terminal layout and auxiliary supply range as the SPAJ131C and SPAJ110C, making it a direct mechanical and electrical replacement in most panel configurations. Setting parameters must be re-entered manually or uploaded via the ABB CAP505 tool. Verify the CT ratio and IDMT curve selection before energizing.

Q2: What pre-shipment testing is performed on each unit?
Every SPAJ140C unit is functionally tested before dispatch. Testing covers overcurrent pickup accuracy (I> and I>>), earth-fault pickup (Io> and Io>>), IDMT trip timing at 2× and 10× pickup, output relay contact operation, and SPA-bus communication port response. A test record is available upon request.

Q3: Can the SPAJ140C communicate with existing SCADA systems via SPA-bus?
Yes. The SPAJ140C supports the ABB SPA-bus protocol (RS-485) natively. It can be integrated into existing SCADA or DCS architectures using an ABB SPA-ZC 17 or SPA-ZC 22 optical/electrical converter. Assign a unique node address (1–254) to avoid conflicts with other relays on the same bus segment.

Q4: What warranty and long-term supply support is available?
All units are covered by a 12-month warranty from the date of shipment. SMARTNEXMSK maintains ongoing inventory of SPAJ140C and related SPAJ/REJ series relays to support both immediate replacement needs and long-term maintenance contracts. Contact our team for volume pricing, lead time confirmation, and retrofit project support.

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