The China Quality Certification Center (CQC) is a national-level certification body that has been approved by the Central Organization Establishment Committee and established by the General Administration of Quality Supervision, Inspection and Quarantine and entrusted by the State Certification and Accreditation Administration. CQC is the earliest, largest and most authoritative certification body for quality certification in China. It has accumulated rich experience in international quality certification for decades, and its business has achieved outstanding results. The number of certified customers ranks first among the national certification bodies and the global certification body. Forefront.

 

The above introduction is taken from Baidu Encyclopedia, detailing that you can find it yourself. After a brief introduction, we believe that the report written by CQC is authoritative. Let's move on to the topic and see what this report explains.

 

The "nominal" cross-sectional area of ​​the cable conductor

 

 

Nominal cross-sectional area: refers to the quantity specified in the product standard and is often used in the table. The value derived from the nominal value is usually checked by measurement under the specified tolerance.

 

From this concept, we can know that this nominal cross-sectional area is only used to describe the specification of wire and cable, just the code name or name of the specification, which is convenient for production management and representation on documents.

 

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The "actual" cross-sectional area of ​​the cable conductor

 

Actual cross-sectional area: It refers to the actual cross-sectional area of ​​the conductor, which is the value measured by the micrometer. For wire and cable manufacturers, the design of a conductor section of a nominal section can meet the standard requirements. It means that the design section (electrical section) under this nominal section should meet the standard requirements, that is, whether the DC resistance meets the standard requirements.

 

With the improvement of the production process of conductor materials and the advancement of science and technology, the advanced production process of oxygen-free copper has been widely applied. The resistivity of copper conductor materials is sufficient to ensure that the copper wire of less than the nominal diameter can meet the requirements of DC resistance of the corresponding specifications.

 

To sum up: At present, the DC resistance is more common in the cable industry, but the actual diameter of the core is smaller than the nominal diameter or the actual cross section is smaller than the nominal cross section, which is in line with the product standard requirements.

 

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Requirements for conductor cross-sectional area in the standard

 

At present, the product standards of major mainstream standards of wire and cable adopt nominal cross-sectional area or specification code to correspond to conductors with different cross-sections. For example, IEC standards, European standards and national standards (GB/T5023, GB/T12706, etc.).

 

Among them, the evaluation of the code of different cross-section specifications is required by the resistance value of the conductor, instead of actually measuring the cross-sectional area of ​​the conductor.

In the national standards GB/T 5023-2008, GB/T 5013-2008 and GB/T 12706-2008, the main provisions of the cable conductors meet the requirements of GB/T3956, the main assessments are: (1) the maximum diameter of the single conductor of the soft conductor and The minimum number of single wires in a hard conductor; (2) the resistance of a conductor at 20 °C.

 

The above is our simple interpretation of this report. I believe that after reading it, you will know whether the cable is qualified, not its cross-sectional area, but resistance. If you encounter such a dispute again, it is better to show him this article and correct this incorrect concept together.