By sion932 
GB 19212.1-2008, titled “Safety of power transformers, power supplies, reactors and similar products – Part 1: General requirements and tests”, is a mandatory national standard in the People’s Republic of China. It was released on September 19, 2008, and officially implemented on June 1, 2009, jointly issued by the General Administration of Quality Supervision, Inspection and Quarantine of the People’s Republic of China and the Standardization Administration of China. This standard is identical to IEC 61558-1:2005 (IDT), ensuring alignment with international safety standards for electrical products while adapting to domestic application scenarios.
1. Scope of Application
GB 19212.1-2008 specifies safety requirements (including electrical, temperature, and mechanical aspects) for power transformers, power supplies, reactors, and similar products. It applies to dry-type transformers, power supplies (including switching power supplies), and reactors (both encapsulated and non-encapsulated windings) that meet the following basic characteristics: rated supply voltage not exceeding 1000V AC, rated supply frequency not exceeding 500Hz, and being stationary or mobile, single-phase or three-phase, air-cooled (natural or forced air cooling), and either standalone or accessory-mounted (not part of the distribution network).
The standard categorizes applicable products into three main types, with clear specifications for each:
- Isolating and safety isolating transformers: For isolating transformers, the rated output is no more than 25kVA for single-phase and 40kVA for three-phase; no-load and rated output voltages range from 50V AC to 500V AC (or up to 1000V AC as per national wiring regulations or special applications). For safety isolating transformers, the rated output is no more than 10kVA for single-phase and 16kVA for three-phase; no-load and rated output voltages do not exceed 50V AC between conductors or between any conductor and protective earth.
- Separating transformers, autotransformers, variable transformers, and small reactors: For both standalone and accessory-mounted transformers, no-load and rated output voltages do not exceed 15kV AC; for standalone transformers, the rated output voltage is not less than 50V AC. The rated output limits are 1kVA for single-phase transformers, 2kvar for single-phase reactors, 5kVA for three-phase transformers, and 10kvar for three-phase reactors.
- Power supplies and switching power supplies with built-in transformers/reactors: For those with isolating transformers, the rated output does not exceed 1kVA, and output voltages range from 50V AC (120V DC ripple-free) to 500V AC (708V DC ripple-free), or up to 1000V AC/DC as per regulations. For those with safety isolating transformers, output voltages do not exceed 50V AC (120V DC ripple-free). For those with separating/autotransformers, the specifications align with the second category above. The internal operating frequency does not exceed 500Hz for power supplies and 100MHz for switching power supplies.
Notably, the standard excludes external circuits and components connected to input/output terminals or sockets of the aforementioned products. Additional requirements may apply for products intended for use in vehicles, ships, aircraft, or special environments (e.g., tropical regions), which should comply with other relevant standards or national regulations.
2. Core Technical Requirements and Test Provisions
GB 19212.1-2008 establishes comprehensive safety requirements to prevent electrical, mechanical, and fire hazards during normal and abnormal operation. The core technical requirements cover multiple aspects, with supporting test methods specified in normative appendices:
2.1 General Design Requirements
Products must be designed and manufactured to ensure no foreseeable risks to personnel or the environment when used, installed, and maintained in accordance with the manufacturer’s instructions, even in cases of inadvertent use during normal operation. For accessory-mounted transformers used with equipment covered by specific appliance standards, tests may be conducted under conditions simulating actual application scenarios with the matched equipment.
2.2 Terminals and Insulation Requirements
The standard revises and supplements definitions of key terms such as safety isolating transformers, accessory-mounted transformers, internal transformers, and rated output current. It also adds new terms including switching power supplies, reactors, intermediate conductive components, and protective earthing conductors. Critical insulation requirements include specified creepage distances, clearances, and through insulation distances, which are detailed in normative appendices A, C, and D, categorized by material groups (CTI values).
2.3 Temperature and Overload Protection
Chapter 7 of the standard classifies products by the maximum rated operating temperature of windings and expected service life under specified conditions, as well as by environmental conditions of the intended use site. Chapter 8 specifies the maximum rated operating temperature of windings (in increments of 5°C) and marking requirements for expected service life, forced air cooling, indoor-only use, and special installation/use notes. Additionally, overload tests for transformers protected by intentionally weak components are added in Chapter 15.
2.4 Electrical Safety Tests
Chapter 18, renamed “Insulation resistance, dielectric strength and leakage current”, adds limits and measurement methods for touch current and protective earthing conductor current. Other key tests include: discharge voltage measurement 1 second after plug removal (Chapter 9), glow wire test (Appendix E), tracking test (Appendix G), and routine production tests (Appendix L). Test circuit examples for single-phase equipment on TN or TT systems with star connection are also provided in the text.
3. Key Revisions from Previous Version (GB 19212.1-2003)
As the first revision of GB 19212.1-2003, GB 19212.1-2008 introduces significant technical changes to enhance safety and align with international standards:
- Revised the document structure and format in accordance with GB/T 1.1-2000 “Directives for standardization – Part 1: Structure and drafting of standards”.
- Updated the standard title to include “reactors” and clarify the scope of power supplies.
- Added a note in Chapter 1 distinguishing transformers, power supplies, and switching power supplies; expanded the scope to include transformers marked with “t”.
- Modified and supplemented 30+ terms and definitions in Chapter 3, covering new product types and safety-related concepts.
- Enhanced marking requirements for winding temperature, service life, and environmental adaptability.
- Added new test items and requirements, such as touch current measurement and overload protection for transformers with weak components.
- Updated requirements for power supply cords of transformers with protection level higher than IPX0 (Chapter 22) and revised through insulation distance requirements (Chapter 26).
- Added new normative appendices (e.g., Appendix R on application of GB/T 16935.1-1997 Clause 4.1.1.2.1) and informative appendices (e.g., Appendix U on transformers with optional marking).
4. Replacement and Succession
GB 19212.1-2008 was officially replaced by GB/T 19212.1-2016 “Safety of transformers, reactors, power supply units and combinations thereof – Part 1: General requirements and tests” on March 1, 2017. The successor standard further refines the scope of application, updates technical requirements, and maintains consistency with the latest international standards. Subsequently, GB/T 19212.1-2023 was released, continuing the evolution of safety standards for transformers and related products in China.
5. Significance and Application Value
During its implementation period, GB 19212.1-2008 played a crucial role in regulating the safety performance of transformers, power supplies, and reactors in China. By adopting international standards (IEC 61558-1:2005) identically, it facilitated the integration of domestic electrical products into the global market while ensuring the safety of personnel and property in domestic applications. The standard provided clear technical guidelines for manufacturers, inspection institutions, and regulatory authorities, promoting the healthy development of the electrical equipment industry. Although superseded, its technical framework and safety principles continue to influence the formulation and implementation of subsequent standards in the field.
References
- General Administration of Quality Supervision, Inspection and Quarantine of the People’s Republic of China, Standardization Administration of China. GB 19212.1-2008 Safety of power transformers, power supplies, reactors and similar products – Part 1: General requirements and tests. 2008.
- IEC 61558-1:2005, Safety of transformers, reactors, power supply units and combinations thereof – Part 1: General requirements and tests.
- Standardization Administration of China. GB/T 19212.1-2016 Safety of transformers, reactors, power supply units and combinations thereof – Part 1: General requirements and tests. 2016.