If your facility runs on switchgear, transformers, breakers, and relays, those assets are only as safe and reliable as the last time they were properly tested. NETA testing is the independent, standards-based process that confirms your electrical power system will perform when it matters — and shut down safely when something goes wrong. Yet many plant and facility managers aren’t sure what NETA testing actually covers, when it’s required, or who is qualified to perform it. This guide breaks it down.
What is NETA testing?
NETA stands for the InterNational Electrical Testing Association, the body that accredits independent electrical testing firms and publishes the ANSI/NETA standards used across North America. “NETA testing” refers to acceptance and maintenance testing of electrical power equipment performed to those standards by qualified, NETA-certified technicians. The goal is simple: verify that equipment is installed correctly, free of defects, and operating within safe tolerances — before a failure causes downtime, damage, or injury. Because NETA-accredited firms are independent third parties, and not the installer or the manufacturer, their results carry weight with insurers, authorities having jurisdiction, and corporate safety programs.
NETA acceptance testing vs. maintenance testing
NETA publishes two core specifications you’ll see referenced in a scope of work:
- ANSI/NETA ATS (Acceptance Testing Specifications) — used on new equipment or new installations to confirm everything was delivered and installed to spec before it is energized.
- ANSI/NETA MTS (Maintenance Testing Specifications) — used on existing, in-service equipment to catch degradation early and keep it running reliably.
Acceptance testing happens once, at commissioning. Maintenance testing repeats on a schedule for the life of the asset.
What does NETA testing include?
A NETA testing scope is tailored to your equipment, but it commonly covers:
- Insulation resistance testing on cables, transformers, and switchgear
- Contact resistance (ductor) testing on bus and connections
- Circuit breaker primary injection and timing tests
- Protective relay testing and calibration
- Transformer testing — turns ratio, power factor, and oil analysis
- Infrared thermography scans of energized equipment
- Ground resistance testing and functional trip testing of protective devices
Each result is compared against ANSI/NETA tolerances and the equipment’s nameplate data, then documented in a report you can hand to an auditor or insurer.
How do you build a testing schedule?
Acceptance testing is a one-time event at installation; maintenance testing then repeats on a schedule set by equipment type, criticality, operating environment, and loading. The 2023 edition of NFPA 70B, Standard for Electrical Equipment Maintenance, elevated electrical preventive maintenance from a recommended practice to a standard, so a documented, condition-based program is now the expectation — and regular NETA testing is what generates the trend data it relies on. For a closer look at how to set intervals for specific equipment, see our guide on how often electrical equipment should undergo NETA testing.
Why NETA testing matters for reliability and compliance
Testing catches loose connections, insulation breakdown, and miscalibrated relays before they become arc flash events or unplanned outages. It also feeds directly into your arc flash study: accurate protective-device settings are exactly what make incident-energy calculations valid, which is why testing and arc flash analysis go hand in hand. Skipping maintenance testing doesn’t save money — it defers a bigger, less predictable cost.
Who performs NETA testing?
NETA testing must be performed by qualified technicians working to current ANSI/NETA standards, ideally through a NETA-accredited or NETA-compliant independent firm. When choosing a provider, confirm they test to the current specifications, carry properly calibrated instrumentation with traceable records, and deliver clear, audit-ready reports. Bowtie Engineering provides NETA-compliant electrical maintenance and testing for industrial and commercial facilities from our base in metro Atlanta, serving clients nationwide. You can review the full ANSI/NETA standards on the InterNational Electrical Testing Association website.
The bottom line
Not sure when your critical equipment was last tested? That uncertainty is exactly the risk NETA testing removes. A right-sized testing program turns your electrical system from a black box into a documented, predictable asset. Contact Bowtie Engineering to scope a NETA testing program built around your facility.