List of relevant testing items of 100 inspectionsThird-party testing institutions support sample sending and door-to-door testing, mainly providing sample testing services for companies, enterprises, public institutions, individual businesses, and university scientific research, and reporting CMA/CNAS/CAL qualifications, which are true and effective.

Report qualification: CNAS, CMA, CAL, etc.

Testing costs: Quotation sample size according to customer needs and experimental

complexity: Choose to send samples or come to the door according to the sample size

In recent years, China's rapid economic development has greatly promoted the expansion and development of the wire and cable industry. The large demand in the market has led to the rampant use of counterfeit and shoddy products, resulting in many personal and property safety accidents. In order to improve the product quality of wires and cables, ensure the safe operation of the power system, and accelerate the stable development of the national economy, it is necessary to have comprehensive testing projects and scientific testing methods. According to the "Code for Acceptance of Construction Quality of Building Electrical Engineering" (GB50303-2002), all raw materials, finished products, semi-finished products, equipment, etc. used in building installation engineering must undergo careful and meticulous quality inspection upon entry, and relevant records must be filled out to confirm compliance with the regulations before they can be applied in construction

The finished product inspection of wires and cables is mainly divided into three types of inspection items: appearance size and structure inspection, electrical performance inspection of wires and cables, and mechanical performance inspection of wires and cables.

Appearance size and structure inspection of wires and cables is the first inspection item of wire and cable quality control, which can be divided into: appearance inspection, size inspection, and structure inspection.

The appearance inspection of wires and cables is to ensure that their surface is round and smooth, without defects and impurities such as burrs, cracks, spots, oil stains that affect normal operation, and to ensure that their corrosion and oxidation degree meet the requirements.

Size detection includes related tests such as outer diameter, thickness, eccentricity, sector height, pitch, cross-section, and density.

. Sampling is required to test the thickness of the insulation layer and the diameter of the wire diameter. The sampling method should take a sample of a section of wire at least at 3 intervals of 1 meter, and then measure it with a micrometer. The insulation layer thickness of various wires and cables should not be less than relevant regulations, and the diameter error of various wire diameters should not be less than 1% of the nominal diameter

The structural testing of wires and cables can be divided into section testing, sheath testing, cable core structure testing, and insulation core testing.

. Structural inspection is actually a final inspection that combines appearance inspection and size inspection, ensuring that there are no defects in the appearance and that the size is roughly correct

The electrical performance of wires and cables accounts for a large part, and its quality directly affects the use of cables. Mainly divided into DC resistance detection, voltage experiment, and insulation resistance detection

DC resistance detection is a test conducted according to the law of resistance, i.e. R= ρ L/S, where ρ Is the resistivity, L is the length of the conductor, and S is the cross-sectional area of the conductor Test method: Measure the DC resistance using a single arm DC bridge or a double arm DC bridge. Measurement range: Double arm bridge measuring 1 Ω or less, single arm or double arm bridge measuring 1 Ω to 99.9 Ω, single arm bridge measuring 100 Ω or less

Conversion of standard DC resistance at 20 ℃: R20=1000Rx/[1+ α (t-20] L, where R20 is the DC resistance at 20 ℃/km, and Rx is the measured value, α Is the temperature coefficient of resistance, and L is the measured length of the sample. When conducting resistance testing, the following precautions should be taken: the temperature change in the testing environment should not exceed ± 1 ℃. When testing the temperature of the environment, the thermometer should be at least 1m away from the ground and not more than 1m away from the sample. When measuring, the appropriate selection of current density should generally not exceed 0.5A/mm for aluminum cores ²， Copper core not greater than 1A/mm ²。

The insulation strength of wires and cables depends on their insulation structure and the ability of insulation materials to withstand electric fields without breakdown damage.

. To ensure the safe operation of wires and cables, voltage experiments are generally required. Voltage experiment: Apply a certain voltage to the product under specific conditions, and determine whether the sample meets the standard by determining whether electrical breakdown occurs during a certain testing time. The voltage and time during the experiment can be selected based on different products. When conducting voltage experiments, it should be noted that there is a metal grounding guardrail and complete emergency protection measures in the experimental area. There is a grounding electrode in the experimental area, and the grounding resistance should be less than 4 Ω

Insulation resistance is an important indicator of the insulation characteristics of wire and cable products. It reflects the product's ability to withstand electrical or thermal breakdown, as well as the insulation material's ability to withstand losses under working conditions.

. The insulation resistance we often refer to is the ratio of the DC voltage U applied on the insulation to the leakage current Ig, i.e. Ri=U/Ig. The commonly used testing methods include DC comparison method and voltage current method. During the experiment, ZC-90 insulation resistance tester and other testing equipment can be selected, and the effective length of the sample, test environment, and test voltage should be executed according to relevant standards. The calculation of the final test result: RL=RX · L, where RL is the insulation resistance per kilometer of length, RX is the insulation resistance of the sample, and L is the effective measurement length of the sample

Detection and testing characteristics:

1. Full coverage of the testing industry to meet different tests;

2. Full coverage of laboratories, local testing nearby;

3. One-to-one service of engineers to make the detection more accurate

, no testing fee is charged for initial inspection

5. Self-service order Express free door-to-door sampling;

6. The cycle is short, the cost is low, and the service is considerate;

7. Authoritative qualifications such as CMA, CNAS, CAL, etc.;

8. The test report is authoritative and effective