What Is the IEC Standard for Impulse Testing?
Sep 18, 2026
Ask which standard governs impulse testing and the short answer is IEC 60060-1 - but that's only the front door. A small family of documents sits behind it, and each one answers a different question: what waveform, measured how, in which environment.
IEC 60060-1: where the waveform lives
IEC 60060-1 is the base standard, and it's the one you cite when someone asks what a lightning impulse actually is. The 2025 edition (Edition 4.0, published April 2025) carries the title "General terminology and test requirements" - a change from the 2010 Edition 3.0, which was titled "General definitions and test requirements." It applies across dielectric tests with alternating voltage, direct voltage, and impulse voltage, and it defines the standard shapes together with their tolerances:
| Waveform | Front time (T1) | Tail time (T2) |
|---|---|---|
| Lightning impulse (LI) | 1.2 µs ±30% (0.84–1.56 µs) | 50 µs ±20% (40–60 µs) |
| Switching impulse (SI) | 250 µs ±20% (200–300 µs) | 2500 µs ±60% (1000–4000 µs) |
Those windows are the whole point. A generator can fire and produce a visually perfect trace that still fails compliance because the tail drifted outside ±20%. Evaluating waveform parameters correctly is the difference between a valid test and an expensive repeat.
IEC 60060-2 and IEC 61083: proving the measurement
Generating an impulse is half the job - the other half is proving you measured it accurately. IEC 60060-2 covers measuring systems: dividers, step response, and accuracy. The 2025 edition (Edition 3) extends applicability to measuring systems used at all standard insulation levels specified in IEC 60071-1. For digitizers and the software that evaluates the recorded trace, IEC 61083-1 and IEC 61083-2 set the requirements.
IEC 60060-3 and IEC 62475: on-site work and impulse currents
Two documents branch off the main line. IEC 60060-3:2006 defines the definitions and requirements for on-site testing, where grounding, limited space, and electromagnetic interference make clean laboratory conditions impossible. Impulse currents are a separate story altogether: exponential current impulses at 1/20 µs, 4/10 µs, and 8/20 µs, plus 10/350 µs lightning current impulses, are now governed by IEC 62475 rather than the 60060 series.
IEC vs IEEE: the same test, different arithmetic
North American projects usually cite IEEE Std 4 instead. The two are broadly harmonized but not interchangeable. Front time is the clearest example: IEC 60060-1 derives it as 1.67 times the 30%-to-90% interval, while IEEE Std 4 measures the 10%-to-90% rise time directly. A test report evaluated to one standard is not automatically compliant with the other, which matters when a transformer built to IEEE requirements is handed a specification referencing IEC.
Applying it to real equipment
Base standards define the test; product standards define the values. Cable impulse testing follows IEC 60230. For transformers, the chopped lightning impulse - a full wave deliberately truncated by a chopping gap, typically within 2 to 6 µs - is a required type test, with test voltage and time to chopping tabulated in IEEE C57.12.00 Table 5.6. If you're specifying a test or buying an impulse generator, confirm which standard the acceptance criteria reference before the equipment is ordered, not after the first waveform fails.
