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What is Load Center?
Load Center mainly is the iron box. The work behavior is similar to the Consumer Unit, but the difference is there are multiple rows and can be applied with more than 1 area. It is suitable for controlling electrical system in medium and large sizes of buildings or industrial buildings which majorly use 3-phase 4-wire power. Load Center is divided into 2 types, which are:
1. Main Lug: will use lug in wiring which is used to connect with 3-phase main lines, and terminal to connect with the neutral line, without the main control unit or Main Circuit Breaker. To distribute the current of this type of Load Center, it will distribute through busbar towards Branch Circuit Breaker, 1-pole or 3-pole. The Branch Circuit will be more or less depending on the ability to withstand the busbar current, such as, 100A, 225A, etc. The use selection is considered based on the number of Branch Circuit required, such as, 12, 18, 24, 30, 36, and 42 (1 Branch Circuit can put in 1 of 1-pole Branch Circuit Breaker). The total use current should not exceed 80% of Load Center rated capacity. For instance, select the rated capacity of busbar 100A the total use current should not exceed 80A. However, because this type of Load Center has no main control unit, the use is often applied with safety switch, or main control device.
2. Main Circuit breaker: is similar to a Main lugs type, but there will be Main Circuit Breaker, 3-pole type MCCB (Molded Case Circuit Breaker). It is served as the primary control unit in distributing current through busbar towards MCB (Miniature Circuit Breaker). The maximum rated withstand current of Main Circuit Breaker must not exceed the rated withstand current of busbar. For instance, the busbar model 100A can be used with Main Circuit Breaker (from 15, 20, 30, 40, 50, 60, 70, 80, 90, and 100A). The use selection, apart from considering on the number of Branch Circuits like Main lugs type, must take the Main Circuit Breaker in to consideration for suitability as well.
Inside the Load Center, it consists of conductor or busbar, arranged from left to right, phase A, B, C respectively. There is the arrangement from left to right, top to bottom. The use selection of Load Center must consists of Branch Circuits not over than 42 circuits, and should provide for several types of loads, such as, branch lighting circuit, branch socket circuit, small branch appliances circuit, specific branch circuit, etc. For branch lighting circuit and branch socket circuit, generally, the loads in the circuit should not exceed 60%, which is consider to reservation for the future loads. However, it should exceed 80% in overall of rated circuit. In case the branch circuit is 3 phases, the arrangement of circuit to be balanced will help electricity use to be efficient. Therefore, the loads should be arranged, i.e., connected to the circuit No. 1, 3, 5, following 2, 4, 6, and 7, 9, 11, so on and so forth. Each circuit should divide load to be equal or nearly equal to one another.
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