By sion932 
As a core national standard in the field of electrical accessories in China, GB/T 11918.1-2014, titled “Plugs, Socket-Outlets and Couplers for Industrial Purposes—Part 1: General Requirements”, plays a crucial role in regulating the design, production, and application of industrial electrical connection accessories. Issued on June 24, 2014, and officially implemented on January 22, 2015, this standard replaces the previous GB/T 11918-2001 and has been revised and improved in response to the development needs of industrial production and technological progress, aligning more closely with international technical trends while adapting to domestic industrial requirements.
1. Scope of Application
GB/T 11918.1-2014 specifies the structural, mechanical, and electrical technical requirements for industrial plugs, socket-outlets, and couplers. It applies to plug and socket-outlets, cable couplers, and appliance couplers primarily for industrial use, both indoors and outdoors, with a rated operating voltage not exceeding 1000 V DC or AC and 500 Hz AC, and a rated current not exceeding 800 A. Notably, these accessories are intended to be installed and used only by trained electrical personnel (as defined in GB/T 2900.73-2008, Definition 195-04-02) or skilled electrical technicians (as defined in GB/T 2900.73-2008, Definition 195-04-01), ensuring the safety and standardization of the installation and use process.
The standard is applicable to electrical accessories used in an ambient temperature range of -25 ℃ to +40 ℃ and designed to be connected only to copper or copper alloy cables. It also covers electrical accessories with screwless terminals or insulation piercing terminals, specifically those in Series I with a rated current not exceeding 32 A and Series II with a rated current not exceeding 30 A. While primarily for industrial use, it does not exclude applications in construction sites, agriculture, commerce, or even households. Additionally, socket-outlets or appliance inlets installed in or fixed to electrical equipment, as well as those intended for extra-low voltage installations, fall within the scope of this standard. However, it does not apply to electrical accessories mainly for household and similar general purposes, and additional requirements may be necessary for special locations such as ships or explosive environments.
2. Key Technical Requirements
2.1 General Design Principles
The design and construction of electrical accessories compliant with GB/T 11918.1-2014 must ensure reliable performance during normal use and pose no hazards to users or the surrounding environment. Under normal operating conditions, these accessories are intended for use in a pollution degree 3 environment as specified in GB/T 16935.1-2008. For other pollution degrees, the creepage distance and clearance must meet the requirements of GB/T 16935.1-2008, and the Comparative Tracking Index (CTI) should be evaluated in accordance with GB/T 4207. Furthermore, the minimum degree of protection for accessories shall be IP23 as per GB 4208, and the combination of plugs, socket-outlets, appliance inlets, and connectors used together must comply with this standard and relevant standard sheets (if any).
2.2 Core Safety Requirements
Electric Shock Protection: The design of electrical accessories must ensure that live parts are not easily accessible when socket-outlets and connectors are wired in accordance with normal use requirements. Additionally, when plugs and appliance inlets are partially or fully mated with matching electrical accessories, their live parts must also be inaccessible. It should be impossible for the pins of plugs or appliance inlets to make contact with the sleeves of socket-outlets or connectors when any contacts are accessible. Compliance is verified through visual inspection and, if necessary, tests using a standard test finger (as shown in Figure 2 of the standard) with an electrical indicator with a voltage of not less than 40 V to check for contact with relevant parts.
Earthing Measures: Electrical accessories with earthing contacts shall be equipped with earthing terminals. For fixed metal-clad electrical accessories with internal earthing terminals, an external earthing terminal may be installed, which shall be visible from the outside unless it is a flush-mounted socket-outlet. Earthing contacts shall be directly and reliably connected to earthing terminals, except for socket-outlets installed in the output circuit of an isolating transformer, whose earthing terminals shall not be connected to the earth. Easily accessible metal parts of electrical accessories with earthing contacts that may become live in the event of insulation failure shall be reliably connected to the internal earthing terminal in terms of structure. A test is required to verify this: a 25 A AC current with an open-circuit voltage not exceeding 12 V is passed between the earthing terminal and each easily accessible metal part, the voltage drop is measured, and the resistance is calculated from the current and voltage drop. In any case, the resistance shall not exceed 0.05 Ω. Additionally, earthing contacts shall be capable of carrying the current specified for phase contacts without overheating.
Terminals and Termination: Terminals shall be securely fixed in the electrical accessory such that connecting or disconnecting conductors does not cause the terminals themselves to loosen. Clamping devices shall not be used to fix any other components. Threaded terminals shall be capable of connecting copper or copper alloy conductors of the nominal cross-sectional area specified in Table 3 of the standard. If the body of the earthing terminal is not part of the metal frame or housing of the electrical accessory, it shall be made of the materials described for terminal components; if it is part of an aluminum or aluminum alloy frame or housing, measures shall be taken to avoid corrosion risks caused by contact between copper and aluminum or aluminum alloy (e.g., using appropriately plated screws or nuts is considered to meet this requirement).
2.3 Other Important Technical Provisions
The standard also includes detailed requirements for dimensions, marking, interlocking devices and retaining devices, aging resistance of rubber and thermoplastic materials, structural design of socket-outlets, plugs and connectors, degree of protection, insulation resistance and dielectric strength, breaking capacity, normal operation, temperature rise, flexible cables and their connections, mechanical strength, screws, current-carrying parts and connections, creepage distance, clearance and distance through potting compound, heat resistance, flame resistance and tracking resistance, corrosion resistance and rust prevention, short-circuit current limiting withstand test, and electromagnetic compatibility. These requirements collectively form a comprehensive technical system to ensure the overall performance and safety of industrial electrical accessories.
3. Main Changes from Previous Version
Compared with the replaced GB/T 11918-2001, GB/T 11918.1-2014 has several significant changes: expanding the rated operating voltage from 690 V to 1000 V and the rated current from 250 A to 800 A; clarifying the user group (trained or skilled personnel); supplementing the scope of application for electrical accessories with screwless terminals or insulation piercing terminals; adding definitions of screwless terminals and insulation piercing terminals; amending the definition of integral switching devices; clarifying the minimum degree of protection as IP23 and specifying requirements for accessory combinations; adding 750 V and 1000 V as rated voltages and supplementing preferred rated currents for Series I (315 A, 400 A, 630 A, 800 A) and Series II (300 A, 350 A, 500 A, 600 A); revising the classification basis for protection degrees; adding new classification items; and supplementing indication requirements for the standard code on products or packaging units.
4. Significance and Application Value
GB/T 11918.1-2014 is classified under CCS K30 (Low-Voltage Electrical Appliances in General) and ICS 29.120.30 (Plugs, Socket-Outlets, Connectors), reflecting its important position in the field of electrical engineering. By establishing unified and strict technical requirements, this standard effectively improves the safety, reliability, and interchangeability of industrial plugs, socket-outlets, and couplers, reducing potential safety hazards in industrial production due to substandard electrical accessories. It also provides important technical support for the standardized development of the domestic electrical accessory industry, facilitating the integration of domestic products with international standards and promoting the healthy development of related industries such as manufacturing, construction, and agriculture.
It should be noted that GB/T 11918.1-2014 will be replaced by GB/T 11918.1-2025 (issued on October 5, 2025, and implemented on May 1, 2026), which is modified based on IEC 60309-1:2021. However, during the transition period, GB/T 11918.1-2014 remains the current effective standard and continues to guide the production and application of industrial electrical accessories in China.
References
[1] General Administration of Quality Supervision, Inspection and Quarantine of the People’s Republic of China; Standardization Administration of the People’s Republic of China. GB/T 11918.1-2014 Plugs, Socket-Outlets and Couplers for Industrial Purposes—Part 1: General Requirements[S]. Beijing: China Standards Press, 2014.
[2] National Standardization Administration of China. GB/T 11918.1-2014[EB/OL]. https://openstd.samr.gov.cn/bzgk/gb/newGbInfo?hcno=E726029B44D9B9128D0114C3C0368D1F, 2014-06-24.
[3] Chinese Standard Service Network. GB/T 11918.1-2014 Plugs, Socket-Outlets and Couplers for Industrial Purposes—Part 1: General Requirements[EB/OL]. https://std.qis.org.cn/qingdao/front/85240500.html, 2014-06-24.