Salam all, this work done many months ago. But, only managed to share it in here now.
ISSUE ON THE OLD DB?
Old DB system only consist 1 elcb to accomodate all mcd going into end ciruit. This includes both Permanent (Lighting circuit and other permanent appliances) and portable (power circuit-Socket outlet) circuit. Picture below shows (Fig X) our old DB arrangement for our house electrical system, where protection device are allocated for each end circuit..
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| Fig 1: Old DB |
Additionally, protection devices on old DB also not properly arranged in order which causing a concern interm of safety and upgradability. Usually, DB system arrange in the order of Main switch, ELCB, MCB for lighting and MCB for power circuit.
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| Fig 2: Old Single line diagram and DB arrangement |
ADDITIONAL LOAD REQUIREMENT
However, as we plan to add more load in the system, 3 more Air Conditioning unit and 2 water heater, 1 circuit for Surveilance supply system and 1 circuit for cooker point and dryer. Therefore, the space in the old DB are not enough to accomodate the number of MCB breaker due to added load. About 7 additional breaker are required, with 1 extra ELCB to accomodate separate end circuit between permanent and temporary (portable) circuit
SURUHANJAYA TENAGA GUIDELINES?
Plus, Old DB system only has 1 ELCB, which not follow the Suruhanjaya Tenaga (ST) guideline as on the Table 1. Therefor, new DB are required to accomodate all the additional protection devices and load and new single line diagram are design and drafted following the guide from ST.
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| Table 1: ST guideline on the Earth Leakage Protection Device [1] |
As the number of load increase in the our electrical system, thus upgrading the electrical system are also required to accomodate larger loading no.
DESIGN PROCESS?
Work is started by basic design with total load for all appliances and devices in the house are added together. From the total load, then both ELCB sizing for permanent circuit and portable circuit can be estimated based on the estimated current going through each ELCB. In this case, estimated value of ELCB shown in Table 2 below. From the total load (total current from permanent circuit and portable circuit) as well,
Main Swicth sizing can also be calculated from the total current passing both ELCB, as shown in Table 2. All these maximum current value are selected from topping up 30%-40% from estimated current. For example, if calculated current passing through ELCB 1 is 24A, then 30% can be added to this value to get nearest possible protection device. In this case, 40A ELCB are enough to protect the circuit from overload current.
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| Table 2: Estimated value of Main switch and ELCB |
NEW SINGLE LINE DIAGRAM
From the value obtained above, new single line diagram are drafted and shown below (Fig 3). All MCB value are estimated as below based on the total current. Full calculation guide can be download in [1]
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| Fig 3: New Single Line Diagram |
New DB installation procees requires several important parts and tools which need to be purchased or ready in advance, before work can be start (Fig 4).
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| Fig 4: DB box, Protection devices and arrangement |
As most of the upgarde are for Air conditioning unit and Water Heater unit, Therefor, 4mm2 size pure copper cable are purchased as in Fig 5. Each cable cost around RM215, totaled around RM645 just for cable. remaining devices are 40A ELCB with 30mA sensitivity, various current value of MCB breaker.
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| Fig 5: 4mm2 Pure Copper Cable for wiring |
FINAL RESULT?
After around 7 hours of work, alone, the final result shows in the Fig 6 below. Additional kWh meter are also added to the DB box to provides important information, such as total current, and total kWh. These critical information can provde better understanding on the electrical consumption usage, which in turn, could give better idea on how electrical consumption improvement can be done on the later stages.
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| Fig 6: New DB installed |
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