This standard specifies the test equipment, sample preparation, test steps, test results and calculations for the flexural test of flexible wires and cables. This standard is applicable to the determination of the dynamic flexural performance of rubber, plastic insulated and sheathed wires and cables under load. GB/T 2951.21-1994 Test methods for mechanical and physical properties of wires and cables Flexural test of flexible wires and cables GB/T2951.21-1994 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Test method for determining mechanical and physical propertiesof electric cables and wiresFlexing test for flexible cables and wires
Test method for determining mechanical and physical propertiesof electric cables and wiresFlexing test for flexible cables and wiresThis standard is equivalent to IEC227-2(1979) and IEC245-2(1980). 1 Subject content and scope of application
GB/T 2951.21-94
Replaces GB 2951.21-82
This standard specifies the test equipment, sample preparation, test procedures, test results and calculations for the flexural test of flexible cables and cables. This standard is applicable to the determination of the dynamic flexural properties of rubber, plastic insulated and sheathed flexible cables and wires under load. This standard does not apply to the following products:
Single-core flexible cables and flexible wires;
Flexible wires with flattened conductive cores: Rubber insulated and sheathed flexible wires and flexible cables with an outer diameter greater than 18.0 mm: Plastic insulated and sheathed flexible wires and flexible cables with an outer diameter greater than 13.0 mm. The general provisions, definitions and regular calibration of test equipment for mechanical and physical properties of wires and cables are specified in GB/T 2951.1. 2 Reference standards
GB/T2951.1-94 General principles for mechanical and physical properties test methods of wires and cables 3 Test equipment
Flexure test machine As shown in Figure 1, the equipment is equipped with a trolley with two pulleys A and B. The arrangement of the two pulleys should make the sample in a horizontal parallel state between the two pulleys. The trolley moves back and forth on a stroke of about 1 mm. The speed is approximately constant at 0.33 m/s. Approved by the National Technical Supervision Bureau on July 7, 1994 and implemented on January 1, 1995
4 Sample preparation
GB/T 2951-21-94
Figure 1 Flexure test machine
A, B--Pulley 11--Trolley; 2--Limit switch 13--Magnetic code Take a sample section of about 5m long from the finished wire and cable. 5 Test steps
5.1 Select the pulley according to Table 1 and Table 2. When the sample is circular, the groove of the pulley should be semicircular. When the sample is flat (or elliptical), the groove of the pulley should be fan-shaped.
5.2 Install the sample on the trolley pulley according to Figure 1, and after gently tightening it, hang F base weights on both ends of the sample according to Table 1 and Table 2. Fix the limit chuck and place it so that the trolley of the sample is always subject to the tension of a magnetic code when it moves back and forth. Table 1 Rubber flexible wire and cable
Flexible wire electric shrinkage type, mm
Braided sheathed flexible wire
Light sheathed flexible wire and cable
1.5-Ss2.5
Heavy sheathed flexible wire and cable
Note: S is the nominal cross section of the conductive core.
Brick weight, kR
Pulley diameter+mm
Flexible wire electric shrinkage type. mm
Non-sheathed fan flat flexible wire
PVC sheathed flexible wire and cable
GB/T 2951.21—94
Table 2 Material flexible wire and cable
Base weight, kg
5.3 Apply load current to each core of the sample as specified in Table 3. Table 3 Core load current
Nominal cross section
0.3, core.4
Polyethylene insulation
Current, A
Rubber insulationWww.bzxZ.net
Nominal cross section
Pulley diameter, mm
Polyethylene insulation
Rubber insulation
5.4 Apply voltage to the core of the sample. The AC voltage applied between the insulated cores of two-core wires is about 220V. For other two-core or one-core wires and cables, the AC voltage is about 380V on the three insulated cores. Other additional cores should be connected to the neutral line. 5.5 Start the flexure test machine
6 Evaluation of test results
6.1 After the sample has been subjected to 15,000 back and forth bends or 30,000 one-way bends, there should be no current interruption or short circuit between the conductors.
6.2 After the flex test, the three-core or more sheathed flexible wire and cable samples shall be stripped of the sheath, the insulated core shall be taken out, and immersed in 20±5℃ water for one piece. According to the provisions of the insulated core voltage test in the product standard, the water immersion voltage test shall be carried out, but the test voltage shall not exceed 2000V.
After the flex test, the samples of other flexible wires or cables shall be immersed in 20±5℃ water for 1h, and then subjected to the immersion voltage test according to the provisions of the finished product voltage test in the product standard, but the test voltage shall not exceed 2000V. Additional remarks:
This standard was proposed by the Ministry of Machinery Industry of the People's Republic of China. This standard is under the jurisdiction of the Shanghai Cable Research Institute of the Ministry of Machinery Industry. This standard was drafted at the expense of the Shanghai Cable Research Institute of the Ministry of Machinery Industry. The main drafters of this standard are Pang Huixu and Zhu Shiqing. This standard was first issued in 1982 and revised for the first time in July 1994.
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