How to distinguish between European cable branch boxes and American cable branch boxes.
At present, the connecting components used in high-voltage cable distribution boxes in China are divided into two major series of products: Europe and America. European machinery and equipment introduced the cable connection definition of outdoor European style box transformers introduced from Europe in the 1980s into the cable distribution box industry, while American machinery and equipment introduced the three-phase five wire software definition of chair European style box transformers introduced from the United States in the 1990s into cable distribution boxes.
1. Differences in machinery and equipment between Europe and America.
There is no established conceptual boundary between European and American machinery and equipment, and the understanding of Chinese professionals is inconsistent. They have some differences in features and prices, so finding their differences is more meaningful for the selection process.
The insulation layer structure of components is different.
There are three layers of plastic outside the insulation of American machinery and equipment, with the innermost layer being a semi insulating shielding layer, the inner layer being the main cable sheath, and the outermost layer being a stable grounding device semi insulating shielding layer, known as the shielding type, which is slightly more expensive. The outer layer of European machinery and equipment is surrounded by double layered plastic, without the topmost layer.
The definition of branch power circuit connection is different.
European machinery and equipment use a series connection support system, with many silicone insulated T machinery and equipment connected in series from the short arm to the ground, generating a main power circuit, and leading out the support system from the excavator extension arm of each T machinery and equipment. This type of connected branch system has some drawbacks: if there is an abnormality in the T-component branch system, it must be removed and the common faulty T-component must be disassembled before it can operate again. Once the common fault is resolved, the component must be reprocessed and reassembled, which is more inconvenient; The series connection head of the main power circuit poses a threat to conductivity stability and reduces dynamic reliability; When there are many connected components, the axis cannot be maintained on the same vertical line, causing some connection head pages to deviate from all normal parts, reducing the compressive strength of the insulation layer and the working ability of the waterproof layer of the page.
The selection and connection of machine equipment in the United States has precisely eliminated the above-mentioned defects of serial connections. The parallel branch system is a set of (three-phase) insulation layer equipment fixed on the inner wall of the distribution box, called a copper busbar plate, which has the function of a current collecting busbar slot. There are several external cone connectors for electrical equipment connected in parallel on the copper busbar, and all cables, including three-phase five wire, small group outgoing lines, branch lines, etc. They are all connected to copper busbar plates. The insulation inside the copper busbar is silver brazed, which has reliable conductivity. However, the three-phase phase spacing is relatively large, and the difficulty of connecting phase cables is slightly higher. The three-phase copper busbar will expand the length and specifications of the shell.
1.3 The smoothness of the mating surfaces varies.
The European mutual cooperation smoothness is designed according to the German standard DIN47636, and the smoothness is relatively small; The smoothness of mutual cooperation in the United States is based on the IEE386 design scheme, with a slightly higher smoothness. Different levels of smoothness will result in the following two differences:
A) The compressive strength of the insulation layer at the middle edge of the machine equipment varies. By integrating the compressive strength of the insulation layer and the rebound force under working pressure, silicone has high ductility. The tighter the working pressure, the higher the compressive strength of the insulation layer. High smoothness, strong resilience, and high compressive strength of the insulation layer. The compressive strength of the insulation layer on American pages exceeds that of European pages.
b) Different waterproof capabilities. The higher the smoothness, the tighter the working pressure of the plastic material on the page, and the better the waterproof layer characteristics. Therefore, the waterproof layer characteristics of American machinery and equipment are slightly better than those of European machinery and equipment.
Differentiate the standards of machinery and equipment in Europe and America.
In the software produced and manufactured in our country, some manufacturers mix European and American structures, which is difficult to distinguish. The following three basic elements will be helpful for everyone to distinguish:
A) From the branch structure of the connector, the parallel branch is a modern American cable branch box, and the series branch is a European classical cable branch box.
B) From the perspective of insulation layer construction, the facility has three layers of plastic (inner shielding layer, main cable sheath, outer interception layer) from the United States, and two layers of plastic (inner shielding layer, main cable sheath) from Europe. For machines and equipment that spray paint non-conductive film on the outer layer of two-layer plastic, due to the high risk of damage to the non-conductive layer during installation or application, and the unreliable characteristics of the grounding device, it cannot be considered as shielded and should still be classified as European machinery and equipment.
c) The cone specifications of machine equipment that match the cone cannot be used as a basis for discrimination. Because the specifications of the cone are only related to the geometric shape specifications, and only involve the compressive strength and immersion ability of the insulation layer, whether it is European or American insulation layer machinery and equipment, the cone can be designed according to American specifications or German standards, resulting in different types of machinery and equipment, such as American cone, American cone, European cone, and European cone.
