Similarities Between IEC and GB Standards

IEC (International Electrotechnical Commission) standards and GB (Chinese National Standards) share many similarities in the electrical field. This is because many Chinese electrical standards are developed by referencing or directly adopting IEC standards. Below is a detailed analysis of their similarities and relationships:

---

1. Purpose and Scope of Standards

• Similarities:
  • Both aim to ensure the safety, reliability, and compatibility of electrical products and systems.
  • They cover a wide range of areas, including the design, manufacturing, testing, installation, and operation of electrical equipment.
• Examples:
  • IEC 61439 Low-Voltage Switchgear and Controlgear Assemblies is highly consistent with GB/T 7251 Low-Voltage Switchgear and Controlgear Assemblies.
  • IEC 60947 Low-Voltage Switchgear and Controlgear is almost identical to GB/T 14048 Low-Voltage Switchgear and Controlgear.

---

2. Technical Content of Standards

• Similarities:
  • Nearly identical in terms of technical requirements, testing methods, and acceptance criteria.
  • For example, IEC 62271 standards for high-voltage switchgear and controlgear are very close to GB/T 11022 standards regarding classification and testing methods (e.g., temperature rise tests, dielectric strength tests).
• Examples:
  • IEC 62271 (High-Voltage Switchgear and Controlgear) vs. GB/T 11022:
    • Identical specifications for temperature rise limits, electrical clearances, and creepage distances.
    • Similar testing procedures, such as power-frequency withstand voltage tests and lightning impulse voltage tests.

---

3. Modes of IEC Standard Adoption in China

• Three Modes of Adoption:
  1. Identical Adoption: Direct translation and implementation without changes.
     • E.g., GB/T 14048.2 is identical to IEC 60947-2.
  2. Equivalent Adoption: Largely consistent with IEC standards, with minor adjustments for local conditions.
     • E.g., GB/T 7251 series modifies environmental adaptability requirements.
  3. Referenced Adoption: Developed based on IEC standards but with significant adjustments for practical needs.
     • E.g., Standards for specific voltage levels unique to China.

---

4. Certification Systems

• Similarities:
  • The certification systems of both standards are compatible:
    • Products meeting IEC standards can obtain CCC certification (China Compulsory Certification) for the Chinese market.
    • Products meeting GB standards that align with IEC standards can obtain international IEC certification (e.g., CE certification).
  • Testing and certification laboratories often recognize both IEC and GB standards.

---

5. Trend Toward Standardization

• Similarities:
  • Increased alignment between IEC and GB standards due to globalization.
  • China has progressively harmonized its standards with international ones, especially in the energy, power, and automation sectors.
  • Large enterprises, such as State Grid Corporation of China, require compliance with both IEC and GB standards, further driving standardization.

---

6. Application in the Electrical Industry

• Practical Examples:
  • Transformers:
    • IEC 60076 vs. GB 1094 series are nearly identical in technical parameters (e.g., temperature rise limits, insulation levels) and testing methods.
  • Low-Voltage Circuit Breakers:
    • IEC 60947-2 vs. GB 14048.2 share the same requirements for short-circuit and overload protection.
  • High-Voltage Switchgear:
    • IEC 62271-200 vs. GB 3906 have very similar specifications for design, testing, and operating conditions.

---

7. Differences and Adjustments

Despite the similarities, there are some differences:

1. Environmental Adaptability:
   • GB standards include stricter requirements for insulation and protection levels to account for China’s humid and highly polluted environments.
2. Voltage Levels:
   • GB standards specify certain voltage levels (e.g., 10kV, 35kV) unique to China, which are not explicitly addressed in IEC standards.
3. Language and Expression:
   • IEC standards are written in English, while GB standards are in Chinese, tailored to local user preferences.

---

Summary

IEC and GB standards are highly similar in the electrical field, especially in the areas of low-voltage equipment, high-voltage equipment, and power transmission and distribution systems. GB standards extensively reference IEC standards while making localized adjustments. This similarity facilitates Chinese companies’ participation in international markets and provides international companies with easier access to the Chinese market.