Overview
IEC TS 62993:2017 provides technical guidance for the determination of clearances, creepage distances and solid insulation requirements for equipment with rated voltages above 1 000 V AC / 1 500 V DC and up to 2 000 V AC / 3 000 V DC. Intended as a transition between low-voltage insulation rules (IEC 60664‑1) and high-voltage practice, this Technical Specification addresses safety-related insulation coordination, electric test methods and altitude considerations (applies up to 2 000 m and gives guidance for higher altitudes).
Key topics and requirements
- Scope and applicability: Guidance for equipment rated >1 000 V AC / >1 500 V DC up to 2 000 V AC / 3 000 V DC; excludes distances through liquids and gases other than air.
- Clearances: Principles for air distances between conductive parts, dimensioning rules, and tables for withstand to transient and recurring overvoltages.
- Creepage distances: Guidance on surface distances to avoid tracking and surface flashover, including treatment for multiple materials, ribs, floating conductive parts and DC-specific considerations.
- Solid insulation: Requirements for solid insulating materials, material group selection, conditioning severities and verification tests to withstand voltage stresses.
- Insulation coordination factors: Overvoltage categories, recurring peak voltage determination, pollution degrees, and material groups used to size insulation.
- Tests and measurements: Electric testing methods, test voltages (with altitude correction factors), procedures to verify clearances and solid insulation, and measurement practices for creepage/clearance.
- Tables and figures: The specification includes dimensioning tables, altitude correction factors, test voltage tables and illustrations for rib geometry and measurement rules.
Applications and who uses it
IEC TS 62993 is practical for:
- Design engineers and insulation coordinators specifying air and surface distances in medium‑high voltage equipment.
- Manufacturers of power converters, switchgear, high-voltage drives, DC systems and other equipment operating in the 1–3 kV range.
- Test laboratories and certification bodies applying electrical tests and altitude corrections.
- Standards and technical committees developing product standards that must bridge the gap between IEC 60664‑1 and higher‑voltage IEC standards.
Practical benefits include safer insulation design, clearer testing requirements, and consistent product safety criteria for equipment that falls between conventional low- and high-voltage standards.
Related standards
- IEC 60664‑1 (insulation coordination for low-voltage equipment up to 1 000 V AC / 1 500 V DC)
- IEC 60071‑1 (high-voltage insulation coordination; starts at higher voltages and does not provide creepage guidance)
- Other referenced test standards (e.g., IEC 60112, IEC 61180) for material tracking and high‑voltage test techniques.
Keywords: IEC TS 62993:2017, clearances, creepage distances, solid insulation, insulation coordination, 2 000 V AC, 3 000 V DC, pollution degree, overvoltage categories, electrical testing.