The test methods specified in the various parts of GB 5023 are listed in this part and the following standards: GB/T 2951-1997 General test methods for cable insulation and sheath materials GB/T 12666.2-90 Fire test methods for wires and cables Part 2: Vertical fire test method for single wires and cables GB 5023.2-1997 Polyvinyl chloride insulated cables with rated voltages up to and including 450/750V Part 2: Test methods GB5023.2-1997 Standard download decompression password: www.bzxz.net

1 General Provisions National Standard of the People's Republic of China Polyvinyl chlorlde insulated cables of rated valtages up to and including 450/750 V Part 2: Test methods 1.1. General requirements The test methods specified in various parts of GB 5023 are listed in this part and the following standards: GB/T 2951—1997 General test methods for insulation and sheath materials of cables GB/T 12666.2—90 Fire test methods for wires and cables Part 2: Vertical fire test method for single wire and cable 1.2 Applicable tests GB 5023.2—1997 Idt IEC 227-2: 1979 Amendment No. 1: 1985
Amendment No.2:1995
The tests applicable to various types of cables are specified by product standards (GB5023.3, GB5023.4, etc.). 1.3 Classification of tests by frequency
According to the definition in 2.2 of GB5023.1-1997, the tests are specified as type tests (symbol T) and (or) sampling tests (symbol S). Symbols T and S are used in the relevant tables of product standards (GB5023.3, GB5023.4, etc.). 1.4 Sampling
If the insulation or sheath adopts embossed embossed marks, the sampling should include the marks, unless otherwise specified. For multi-core cables, except for the tests specified in 1.9, the samples taken should not exceed three cores (if color-coded, take different colors) for testing.
1.5 Pretreatment
All tests shall be carried out after the insulation or sheath is stored for at least 16 hours after extrusion. 1. 6 Test temperature
Unless otherwise specified, the test shall be carried out at ambient temperature. 1.7 Test voltage
Unless otherwise specified, the test voltage shall be an approximate sinusoidal waveform of AC 49Hz~61Hz, with the ratio of peak value to effective value equal to /2±7%.
All voltages are effective values.
1.8 Inspection of color and mark resistance
Use a ball of absorbent cotton or a piece of cotton cloth soaked in water to gently wipe the manufacturer's name or trademark, product model, rated voltage, insulation core color or digital mark for a total of 10 times. The inspection result shall meet the requirements of the standard. 1.9 Insulation Thickness Measurement
Approved by the State Administration of Technical Supervision on July 30, 1997 and implemented on September 1, 1998
1. 9. 1 Procedure
GB 5023. 21997
The insulation thickness shall be measured in accordance with 8.1 of GB/T2951.1-1997. A cable sample shall be taken from three locations at least 1 m apart.
For cables with 5 cores or less, each core shall be checked. For cables with more than 5 cores, any 5 cores shall be checked to see if they meet the requirements. If it is difficult to remove the conductor, it can be extracted by placing it on a tensile machine, or a section of the insulated wire core sample shall be immersed in mercury until the insulation becomes loose and the conductor can be extracted.
1.9.2 Evaluation of test results
Take 3 insulation samples from each insulated wire core and measure the average value of 18 values ​​(expressed in mm). The value should be calculated to 2 decimal places and rounded as follows. Then take this value as the average value of insulation thickness. When calculating, if the second decimal place is 5 or greater than 5, the first decimal place should be rounded up to 1. For example, 1.74 should be rounded to 1.7, and 1.75 should be rounded to 1.8.
The minimum value of all measured values ​​should be taken as the minimum thickness of insulation at any location. This test can be carried out together with any other thickness measurement, such as the test item specified in 5.2.4 of GB5023.11997. 1.10 Sheath thickness measurement
1. 10. 1 stepwww.bzxz.net
The thickness of the sheath should be measured in accordance with 8.2 of GB/T2951.1-1997. A cable sample should be taken from each of the three locations at least 1 m apart. 1.10.2 Evaluation of test results
The average value of all values ​​(expressed in mm) measured from the three sheath sections should be calculated to 2 decimal places and rounded off as follows: Then take this value as the average value of the sheath thickness. When calculating, if the second decimal place is 5 or greater than 5, the first decimal place should be rounded off by 1. For example, 1.74 should be rounded off to 1.7, and 1.75 should be rounded off to 1.8.
The minimum value of all measured values ​​should be taken as the minimum thickness of the sheath at any location. This test can be carried out together with other thickness measurements, such as the test items specified in 5.5.4 of GB5023.1-1997. 1.11 Measurement of overall dimensions and ovality
Three samples should be taken as specified in 1.9 or 1.10. The measurement of the outer diameter of any round cable and the measurement of the outer dimensions of flat cables with a width not exceeding 15 mm shall be carried out in accordance with the provisions of 8.3 of GB/T2951. —1997.
When the width of the fan-shaped cable exceeds 15 mm, it shall be measured using a dry ruler, projector or similar instrument. The average value of the measured values ​​shall be taken as the average outer dimension. The inspection of the ovality of the flat sheathed cable shall be measured at two locations on the same section. 2 Electrical performance test
2.1 Conductor resistance
The conductor resistance inspection shall be carried out on each conductor on a relay sample with a length of at least 1m, and the length of each cable sample shall be determined.
If necessary, the resistance of the conductor at 20C and a length of 1km can be converted according to the following formula. Rm -R 2+ × 100
Formula: t——sample temperature during measurement, ℃; Rzo——conductor resistance at 20C n/km; R,——conductor resistance of cable with length L meters at tC, D; L——cable sample length, m (the length of the finished sample, not the length of a single insulated core or single wire). 2.2 Voltage test for finished cables
GB 5023. 2-1997
The finished cable delivered, if without metal layer, shall be immersed in water. The sample length, water temperature and immersion time shall be as specified in Table 3 of GB5023.1-1997. The voltage shall be applied in turn between all other conductors and metal layer (if any) or water connected together for each conductor pair, and then the voltage shall be applied between all the conductors connected together and metal layer. For the applied voltage and withstand voltage time, please refer to the various provisions in Table 3 of GB5023.1-1997. 2.3 Insulated core voltage test
This test is applicable to sheathed cables and flat non-sheathed flexible wires, but not to flat copper-clad flexible wires. The test should be carried out on a 5m long cable sample. The sheath and any other covering layer or filler should be stripped without damaging the insulating core.
For sectoral non-sheathed flexible wires, a small section should be cut on the insulation between the insulating cores, and the insulating core should be torn 2Ⅱ long by hand. For the applied voltage and withstand voltage time, please refer to the various provisions in Table 3 of GR5023.1-1997. The insulated core should be immersed in water according to the provisions of Table 3 of GB5023.1-1997, and the voltage should be applied between the conductor and the water. For the applied voltage and withstand voltage time, please refer to the various provisions in Table 3 of GB 5023.1-1997. 2.4 Insulation resistance
This test is applicable to all cables and shall be carried out on a 5 n long insulated wire core sample. Before measuring the insulation resistance, the sample shall be subjected to the voltage test specified in 2.3, or if not applicable, the voltage test specified in 2.2. The sample shall be immersed in water preheated to the specified temperature, and its two ends shall be exposed to the water surface for about 0.25 m. The sample length, water temperature and immersion time are specified in Table 3 of GB 5023. 1-1997. Then a DC voltage of 80 V to 500 V shall be applied between the conductor and the water.
The insulation resistance shall be measured 1 min after the voltage is applied and converted to a value of 1 km. The measured value shall not be lower than the minimum insulation resistance specified in the product standard (GB5023.3, GB5023.4, etc.). The insulation resistance value specified in the product standards (GB5023.3, GB5023.4, etc.) is calculated based on the volume resistivity of the insulation of 1×103a·m, and the calculation formula is:
R = 0.0367lg
Where: R—insulation resistance, Mn·km
D-—nominal outer diameter of insulation;
d—conductor circumscribed circle diameter or nominal inner diameter of copper-covered soft wire insulation. 3 Mechanical strength test of finished soft cable
3.1 Bend test
Test requirements are shown in 5.6.3 of GB 5023.1-1997.1. This test is not applicable to copper-clad soft wires or single-core soft conductor cables for fixed wiring. In addition, this test is not applicable to cables with more than 2 layers of concentric stranding and more than 18 stranded cores. This test should be carried out according to the equipment shown in Figure 1. The cable is installed in a horizontal state between two pulleys A and B on a movable trolley C. The trolley moves back and forth at a constant speed of about 0.33m/s over a distance greater than 1m. Take a flexible cable sample of about 5m long and place it on the pulley and tighten it, as shown in Figure [. A heavy chain is loaded at each end of the flexible cable. The weight of the heavy hammer and the diameters of pulleys A and B are listed in the following table and Table 1. Flexible cable name
Fan-shaped unsheathed flexible cable and indoor decorative lighting flexible cable Lightweight polyurethane sheathed flexible cable
Ordinary polyvinyl chloride sheathed flexible cable
Weight of heavy hammer
Pulley diameter
Flexible cable name
Nominal cross section not exceeding 1mm2
Nominal cross section 1.5 mm2 and 2.5 mm
Nominal cross section
Weight
GB5023.2—1997
Table (end)
Pulley diameter
Number of cores"
Weight
Nominal cutting surface
Weight of hammer
Pulley diameter
Clear pulley diameter
1) Cables between 7 and 18 cores but not specified in this table are "non-preferred" structures. During the test, the weight of the hammer and the pulley diameter can be selected from the specified values ​​of the number of cores in the next table of the same cross section. There is a semicircular groove for the pulley of the round relay and a flat groove for the fan-shaped cable. Install the limit clamp D so that when the trolley leaves the weight, it can always apply a pulling force with the help of the weight to make the trolley move back and forth. A current of about 1A should pass through each conductor of the sample per square millimeter. For 2-core cables and 3-core light sheathed cables, the voltage applied between the conductors should be about 220V AC. For all other cables with 3 cores or more, the voltage applied to the 3 conductors should be about 380V three-phase AC, and the other conductors should be connected to the neutral line. Fo
3.2 Bending test
Figure 1 Flexure test equipment
The test requirements should be in accordance with 5.6.3.2 of GB5023.1-1997. o
GB 5023.2- 1997
Take a soft wire sample of appropriate length, fix it on the equipment shown in Figure 2, hang a 0.5kg weight at its end, and the conductor passes about 0. 1 A The current.
The specimen shall be bent back and forth 180° in a plane perpendicular to the conductor axis. When bent to the extreme position, it shall be at 90° to each side of the conductor axis.
The bending frequency is 60 times per minute.
If the specimen does not meet the requirements after the test, two more specimens shall be taken for repeated tests, and both shall meet the requirements. 90°
Specimen fastening device
One specimen
One bending axis
Figure 2 Bending test equipment
3.3 Load fracture Core test
Test requirements shall be in accordance with 5.6.3.3 of GB5023.1-1997. Dimensions: mm
Take a soft wire sample of appropriate length, install one end of it on a rigid support, and hang a weight of 0.5kg at the sample 0.5m below the support point. A current of about 0.1A passes through the conductor. During the test, lift the heavy chain to the support point and let it fall freely, repeating 5 times. 3.4 Insulation core tearing test
Test requirements shall be in accordance with 5.6.3.4 of GB5023.1-1997. This test is applicable to flat unsheathed soft wires. On a short section of soft wire sample, cut the insulation between the insulated wire cores, and use a tensile machine to measure the force required to tear off the insulation at a speed of 5mm/s.
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