Interpretation And Analysis Of Quality Inspection Report For Terminal Blocks

The quality inspection report of terminal blocks is an important basis for evaluating the performance and safety of terminals. Its interpretation should focus on key inspection items, compliance with standards, and practical significance. The following will be discussed from three aspects: testing content, standard basis, and result analysis:

1、 Analysis of core testing items

Physical Performance Testing

Including wire stripping quality (such as conductor cuts, copper wire missing quantity must meet standards, such as 0 missing wires allowed for 0.35mm ² wires), conductor crimping height/width (must meet terminal manufacturer's mold parameters, such as crimping height deviation ± 0.1mm), insulation crimping form (such as symmetrical crimping requiring at least 120 ° insulation layer wrapping).

For example, in a terminal inspection, after stripping the 0.5mm ² wire, there were no missing copper wires, and the crimping height was 1.2mm (in accordance with the 1.1-1.3mm standard). The insulation crimping symmetry reached 130 °, and it was judged as qualified.

mechanical testing

Verify the connection strength through tensile testing, such as testing the minimum cross-sectional line for double wire crimping. A report shows that the tension of the 0.75mm ² wire reaches 25N (exceeding the standard requirement of 20N), indicating a firm crimping.

Electrical performance verification

Voltage drop test is a key indicator, and the voltage drop difference after 200 hours of power on should be less than 0.3mV/A. During the 2-hour and 200 hour tests, the voltage drop of a certain terminal was 1.2mV and 1.4mV, respectively, with a difference of 0.2mV, which meets the requirements.

2、 Standard basis and compliance

Testing must comply with international/national standards, such as GB (China) and IEC (International Electrotechnical Commission). For example, the inspection report of a certain terminal box clearly indicates that it is based on GB 7251.1-2013 "Low voltage switchgear and control equipment", and its insulation resistance, withstand voltage strength and other items have passed.

3、 Result analysis and improvement suggestions

Qualification judgment

If all testing items meet the standards (such as the tension, voltage drop, and insulation resistance of a certain terminal), the report conclusion is "qualified" and it can be put into use.

Handling of non-conforming items

If a certain item does not meet the standard (such as the crimping height exceeding 0.3mm), the reason (such as mold wear) needs to be analyzed, and the process needs to be adjusted before re inspection.