TECO GROUP provides professional primary injection testing services that verify your circuit breaker trip units will respond correctly under real fault conditions. Unlike secondary injection which tests only the relay, a primary injection test applies actual current — up to 2,000A — through the entire protection circuit including the breaker, current transformers, wiring, and trip unit. This end-to-end verification confirms that every component in the protection chain functions as designed, giving you confidence that your LV switchgear and MV installations will safely disconnect fault currents and protect people, equipment, and your facility.
Our primary injection testing capabilities include:
- Primary current injection up to 2,000A for 10 minutes using ZERA UB 2004 I test equipment — suitable for testing MDB, MCC, and SMDB breaker trip units across all ratings.
- Secondary current injection up to 100A for 1 minute using ZERA RP 7440 — for relay-only verification and protection coordination checks.
- Voltage injection testing using ZERA UB 2001 U for undervoltage and overvoltage trip verification.
- End-to-end testing of the complete protection circuit — breaker, CT, wiring, relay, and trip coil — confirming the entire chain operates as a system.
- Trip time measurement and trip current verification against manufacturer settings and design protection coordination curves.
- Applicable to both new installations (factory acceptance and commissioning) and existing installations (periodic maintenance verification).
- Testing of all breaker types — MCCB, ACB, and ATS changeover breakers — in LV and MV switchgear.
Why primary injection testing is essential for your electrical installation:
- Confirms breakers will actually trip at the correct fault current — not just that the relay is calibrated, but that the entire circuit responds end-to-end.
- Detects wiring errors, incorrect CT ratios, faulty trip coils, and mechanical failures that secondary injection alone cannot reveal.
- Required for commissioning new MDB and MCC installations to verify protection before energisation.
- Recommended as part of periodic maintenance testing to ensure protection integrity has not degraded over time.
- Essential for hospital and critical facility switchgear where protection failure could endanger lives.
- Complements our comprehensive electrical testing and thermal imaging inspection services for complete installation verification.
TECO GROUP performs primary injection testing for all project types:
- Commercial buildings — MDB and SMDB breaker trip verification before occupancy handover.
- Hospitals — critical protection testing for ATS, MDB, and emergency distribution panels.
- Hotels — commissioning tests for new switchgear installations.
- Factories — MCC protection verification for motor feeder breakers and VFD input breakers.
- Wastewater treatment plants — breaker trip testing across MV substations, MDB, and MCC installations.
- Pumping stations — protection verification for autotransformer starter and soft starter breakers.
If you are interested in having your breakers tested, get in touch with us using the contact form →
