IEC 60664-1:2020

Overview

IEC 60664-1:2020 - Insulation coordination for equipment within low-voltage supply systems - Part 1: Principles, requirements and tests - defines principles and requirements for insulation coordination of equipment rated up to AC 1 000 V or DC 1 500 V connected to low-voltage systems. It applies to frequencies up to 30 kHz, covers use up to 2 000 m altitude (with guidance for higher altitudes), and sets out requirements for clearances, creepage distances and solid insulation criteria. The standard also describes electrical test methods (impulse, AC, DC, partial discharge and high-frequency) used to verify insulation coordination.

Key topics and requirements

• Voltage and overvoltage categories: definitions for steady-state, recurring peak, temporary and transient overvoltages used to determine insulation levels and test voltages.
• Clearances and creepage distances: dimensioning criteria, environmental factors (pollution, humidity, altitude, temperature) and special considerations for functional, basic, supplementary and reinforced insulation.
• Solid insulation requirements: stress, material characteristics and withstand criteria, including partial discharge limits and conditioning.
• Electrical testing and measurements: test voltages, partial discharge methods (normative Annex C), impulse/AC/DC and high‑frequency tests, and measurement of attenuation of transient overvoltages.
• Environmental and installation factors: altitude correction (updated Table F.10), pollution degrees, and limitations (excludes liquid insulation, gases other than air, and compressed air).
• Practical guidance tools: new flowcharts in Annex G (clearances) and Annex H (creepage distances) to support design decisions.
• Exclusions & cautions: minimum clearances in the standard do not apply where ionized gases are present; special technical-committee requirements may be needed.

Applications

IEC 60664-1 is essential for professionals involved in the design, testing and certification of low-voltage electrical equipment. Typical users include:

• Design and product engineers specifying insulation coordination, clearances and creepage for PCBs, power supplies, controlgear and consumer/industrial devices.
• Test laboratories and compliance teams performing dielectric and partial discharge testing.
• Manufacturers and safety managers preparing technical documentation for conformity assessment.
• Technical committees developing product-specific standards that require clearances, creepage and insulation tests.

Related standards

• This edition has the status of a basic safety publication in accordance with IEC Guide 104.
• For complete compliance, IEC 60664-1 should be used alongside other IEC product and test standards relevant to the specific equipment family (e.g., product safety and dielectric test standards).

Keywords: IEC 60664-1, insulation coordination, low-voltage, clearances, creepage distances, solid insulation, partial discharge, dielectric tests, altitude correction.