Low-voltage circuit breaker wiring method - Database & Sql Blog Articles

1. When the circuit breaker is installed vertically or horizontally, the parameters of the nameplate on the panel of the circuit breaker are used as the parameters. The terminal above the circuit breaker is used as the incoming end of the power supply, also known as the power supply terminal. The terminal of the load acts as the connection end of the load, also known as the load end. This type of wiring is called the upper incoming line; otherwise, the power supply end of the circuit breaker is used as the load end, and the load end is used as the power supply end. Call the next line.
2, the typical bus-connected circuit breaker connection is usually the upper line mode, but often because of the installation occasion, the circuit breaker requires the incoming line mode wiring. For example, the power supply is below the power distribution cabinet, and it is convenient to connect the power supply to the load end of the circuit breaker. There are also two or two rows of circuit breakers installed above and below the cabinet. The power supply line is introduced from the middle part, up and down. Two or two rows of circuit breakers are connected, which are the wiring mode of the lower incoming line and the upper incoming line. There is also a special occasion, no matter what measures are taken to avoid the way of entering the line, the classic form of maternal connection in building electrical.
In actual operation, three locks and two keys are commonly used to ensure the reliability of the chain. For example, the HSW1 series intelligent universal circuit breaker has this function. All three circuit breakers have the same lock, which can reliably lock the mechanism. For the buckle part, the three circuit breakers can only be equipped with two identical keys. When the key is inserted and unlocked, the circuit breaker mechanism can operate and the circuit breaker can be normally closed. The QF3 is not equipped with a key during normal operation and the circuit breaker QF3 is in the off position. When any of the two power sources, such as QF2, cannot supply power, move the QF2 key to QF3, then QF2 is disconnected, QF3 can be closed, and all loads are powered by the same power supply through QF1 and QF3. At this time, QF3 is the upper incoming line mode. . When QF1 cannot supply power, all loads are powered by the same power supply through QF2 and QF3. At this time, QF3 is the lower incoming line mode. Therefore, for the circuit breaker QF3, no matter what the connection method, for the two power supply, there is always one of the upper line mode, one is the lower line mode, so this kind of occasion can not avoid the adoption of the next line. Line of.
3. Different structures have different ways of entering and lowering the line. Is it possible for all circuit breakers to satisfy both the upper and lower lines? According to GB14048.2-94 national "Low-voltage switchgear and control equipment low-voltage circuit breaker" standard: on the nameplate of the circuit breaker or the relevant information provided in the manufacturer, the power supply end and the load end are specified (if necessary if). The DW15-200, 400, and 630 versatile circuit breakers are clearly indicated in the manufacturer's sample or instruction manual: the wiring of the circuit breaker is the upper incoming line, and the user cannot reverse the power supply end and the load end. In the DZ20 series molded case circuit breaker industry standard JB589-1997, it is stipulated: "The circuit breaker has the power supply end and the load end mark, respectively, with 1, 3, 5 indicating the power supply end, and 2, 4, and 6 indicating the load end.". Some manufacturers directly engraved "1, 3, 5" and "2, 4, 6" Arabic numerals on the molds of the DZ20 series. Some plastic case circuit breakers are directly pressed with English "Line" and "Load", or the Chinese characters "power end" and "load end", as well as self-adhesive signs, "Line" on the sign. End), Load (load end), all words indicate that the circuit breaker can only enter the line. Most of the universal circuit breakers are specified in the sample or in the manufacturing instructions. Without such identification or description, it means that they can be the power supply end and the load end.
The same is the DW15 series, the circuit breaker with the frame current greater than 630A, such as the circuit breaker with the frame current of 1600A, 2500A, 4000A, can not only enter the line, but also the incoming line, HSW1 series, DW45 series intelligent universal circuit breaker The specifications used in the middle can be used for the upper and lower incoming lines, and in the type test process, the limit circuit breaker is divided into short capacity, the circuit breaker breaking capacity and the short-time withstand test are all tested by the lower line method. Meet the standards adopted by the circuit breaker.
Why do some circuit breakers only go up the line and can't go down the line, and some circuit breakers can both enter the line and the line? This is mainly related to the structure of the product. The distance from the static contact to the terminal of the circuit breaker is short, and the distance between the movable contact and the movable contact rod connected to the soft coupling through the trip unit to the connection end is long. The terminal connected to the static contact is used as the power supply end. The isolation between the arc-extinguishing system between the moving and static contacts and the phase-interval arcing between the power terminals are fully considered in the design. Dynamic and static contacts and connecting parts, due to insulation and isolation measures, as long as the arc extinguishing system normally extinguishes the arc, the circuit breaker can also be normally broken.
However, when the circuit breaker using the lower incoming line is disconnected, the connecting parts of the phase moving contacts are all charged bodies after the dynamic and static contacts are disconnected, and in a long area, such as the gap between the shafts, there is a gap. The arc generated during the ultimate breaking is mostly extinguished in the arc extinguishing system due to the electric power and the arc extinguishing chamber. However, a small part of the charged free gas meets the adjacent phase charged body, which may cause phase-to-phase short circuit and damage the circuit breaker. Normally disconnected. The DW15 series has a frame current of 1600A and above. Because the phase spacing is larger than the circuit breaker current of 630A, and the isolation and insulation methods are used, although the DW15 series is the same, it can meet both the upper and lower lines. Claim. In the HSW1 and DW45 series, each phase is separated into separate chambers by the molded shell structure, so the specifications can be used for the upper and lower lines.
4. Summary At present, HSW1, CM1, DZ20, and H, TO, TG series of molded case circuit breakers with more domestic applications can only be used on the incoming line, but not in the incoming line. The structure is different and the extent of the decline should be different. Therefore, the user should press the limit breaking ability test report of the incoming line to judge the drop. If the circuit breaker is vertically flipped, the original load end of the circuit breaker is on the top, and as the power supply end, the circuit breaker is far below the power supply end. As the load end, the working condition is more severe than that under the vertical formal installation, so the short circuit is cut off at the limit. In addition to the phase-to-phase short circuit caused by the installation form of the under-input line, the direction of the hot air flow is upward due to the arc-breaking at the lower part, and the arc entering the arc chamber is also slightly disadvantageous.
When the circuit breaker is installed horizontally on the incoming line, when the limit circuit is broken, the arc is mainly driven by the electric power to enter the arc extinguishing grid. Even if the hot gas generated when the contact is disconnected is upward, the arc is still above. The metal grid is only in the horizontal position of the arc-extinguishing chamber. When the short-circuiter is installed horizontally, the performance of the grid is not affected. Of course, the lateral installation of the circuit breaker cannot be made into the line. If it is a leakage circuit breaker, it is even more difficult to reverse the upper incoming line and the lower incoming line, because the tripping coil of the electronic leakage circuit breaker is instantaneously charged only when the action signal is obtained, and the power is cut off immediately after the leakage circuit breaker opens the breaking circuit. If the limit is opposite, the voltage is still applied to the trip unit coil after the leakage circuit breaker is actuated, the coil will be burned, and the entire earth leakage circuit breaker loses the leakage protection function.

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