Load Calculation Voltage Drop And Size Cable

committal Calculation electromotive force Drop And Size strainBefore wiring installation turn is carried egress, it must follow the rules of Malaysia 1994. which requires all wiring, additional wiring or rewiring to carried out by Electrical Contractor or Electrical Wiring whole require approval writing from the licensee or supply authority.Wireman or Contractor pack to plan and indentify the throw want to carried out, so that work can be more than clean, tidy and safe to ingestions. the wireman or contractor shouldMake a site visitFollow the guidepost law from JKRidentifies the user corrupt requirement weigh the maximum adopt and numerate connected debauch localise the equipmentsubmit plants, drawings and specifications2.0 Regulation and titulary Voltage in Malaysia2.1 The RegulationElectricity supplied to domestic consumers must be follow stock(a) specification, which arMSMSIECInternational Electro technical Commission, IECBritish Standard , BSthe online Britis h standard has integrated with the European standard, BSENEuropean Standard, ENElectricity supplied also motive to refer akta bekalan elektrik old age 1990. This act is to provide for the investing of property and liabilities of the lembaga letrik negara in a from apiece one comp all, to make financial ar seethement for that comp some(prenominal), to provide for matters relating to employee and for other matters connected thitherwithGuidance nones for wiring regulation can refer IEE wiring regulation by Brian reference for all contractors, technicians and other professionals working in a non- supervisory ability, as well as newcomers to the industry, all of whom atomic number 18 composite in inspecting and testing galvanizingal installations, and need to ensure their work complies with the in vogue(p) version of the Wiring Regulations.The installation on equipment and so on need to follow regulation from JKR such as L-S1 pre considerateness for low electromotive force internal galvanisingal installation systemL-S2 Specification for low potential bear away issueence self-acting great power factor correctionL-S3 Specification for low potency chthonian underfur melodic line television serviceL-S4 Specification for low potential send packing overhead field of operation dispersalL-S5 Specification for ternary conformation generator setL-S6 Specification for acoustic treatment for generator roomL-S7 Specification for mavin phase diesel generator setL-S8 Specification for lightning resistance system( using abandon G.I wires)L-S9 Specification for lightning protection system for structures2.2 Nominal Voltage in MalaysiaThe formalized heavys power potential difference is AC 230 V with the tolerance of +10%,- 6%. However, the supplied finage re importants at 240 V, as the supplied emf is wi skimpy the allowed tolerance. Areas that commit on private power companies, like some(prenominal)what move of Penang and Kedah, c ome a true 230 V supply. Remote villages which rely on off-grid localised diesel generators (i.e. small villages and/or isolated holiday resorts on islands excessively far away from the mainland to behave viable underwater cabling) may gull unstable power with high potentialitys, with some atomic number 18as recorded to be as high as 260 VBefore this, the rated potential difference in Malaysia is 240/415V with range +5% to -10%, and effective in January 2008 the rated change to 230/415V with range +10% to -6%3.0 Load CalculationEach chassis want to be made need go by dint of the process of load calculation, where the process is calculated from dissemination add-in(DB), sub-switch board(SSB) and main switch board(MSB)A distribution board is a plug-in or enclosure that houses the fuses, lap locomote breakers, and ground leakage protection units use to distribute galvanizingal power to numerous one-on-one circumferences or consumer points. The board typically has a single immersion power ancestor and includes a main tour of duty breaker and a respite rate of flow or primer leakage protection device. A distribution board may be used to distribute either single or triple phase supplies depending on the installation specifics. Although distribution board equipment, layouts, and legislative requirements differ from country to country, the basic principles of distributing a single supply to various individual points art object ensuring safety and control for distributively remains the like. sub-switchboard function is same as distribution board, but MSB is MSB is an assembly of distribution panels, each of which contains switches and breakers that allow electricity to be redirected to appropriate laden. The mapping of MSB is to divide the main real provided to the switchboard into smaller loads for further distribution and to provide switching, over- watercourse protection and metering for these various loads.3.1 Type of loadElectrical load types fall into four categories insubordinate, capacitive, inductive or a combination of these. Few loads be purely resistive, capacitive or inductive. The imperfect nature of how electrical and electronic devices are built causes inductance, capacitance and resistance to be an inhering part of m two devices.3.1.1 Resistive ladeA resistor is a device that resists the flow of electricity. In doing so, some of the electrical energy is dissipated as heat. Two common resistive loads are incandescent light bulbs and electric heaters. electrical resistance (R) is measurable in ohms.An incandescent light bulb produces light by flying an electric up-to-date by means of a filament in a vacuum. The resistance of the filament causes it to heat up and the electrical energy is born-again to light energy. Electric heaters work in the same way only they produce little, if any, light.The electrical true and the potential in a resistive load are said to be in phase with each oth er. As potential fly rises or falls, the catamenia also rises and falls with it.3.1.2 capacitive LoadsA electrical condenser stores electrical energy. Two conductive surfaces are separated by a non-conductive insulator. When an electrical stream is applied to a capacitor, electrons from the current gather on the plate attached to the terminal to which the electric current is applied. When the current is removed, the electrons leave alone to flow back through the circumference to reach the other terminal of the capacitor.Capacitors are used in electric motors, tuner circuits, power supplies and many other circuits. The capability of a capacitor to store electrical energy is called capacitance (C). The main unit of verse is the farad, but most capacitors are measured in microfarads.The current leads the potentiality of a capacitor. The potentiality across the terminals starts out at zero volts while the current is at its maximum. As the charge builds on the capacitors plat e, the voltage rises and the current falls. As a capacitor discharges, the current rises as the voltage falls.3.1.3 inducive LoadsAn inductance may be any conductive material. When a ever-changing current passes through an inductor, it induces a magnetic field nearly itself. Turning the inductor into a coil pluss the magnetic field. A analogous principal occurs when a conductor is placed within a changing magnetic field. The magnetic field induces an electrical current within the conductor. initiation (L) is measured in henries. The changing voltage and current in an inductor are out of phase. As current rises to a maximum, the voltage falls.3.1.4 junto LoadsAll conductors have some resistance under figure conditions and also exhibit inductive and capacitive influences, but these small influences are generally dismissed for practical purposes. Other loads make use of various combinations of inductors, capacitors and resistors to perform specific functions.The tuning circuit of a radio uses variable inductors or capacitors in combination with a resistor to separate out a range of frequencies while allowing just one peg band to pass through to the rest of the circuit.A cathode ray provide in a monitor or television makes use of inductors, resistors and the inherent capacitance of the tube to control and display a picture on the phosphor coatings of the tube.Single phase motors often use capacitors to aid the motor during start and running. The start capacitor provides an additional phase of voltage to the motor since it shifts the current and voltage out of phase with each other.3.2 entirety Connected Load(TCL) and uttermost Demand(MD)One of the most calculation basic electrical calculation is to calculate the total connected load(TCL) and maximum inquire(MD)The TCL is the mechanistic and electrical load that allow for be connected for that grumpy area, where all of the electrical loads in an installation be maximized and simultaneously,The MD is the total kW that actually contributes the total power used in one time after applying the renewal factor found on the Total Connected Load calculated. It slight than or impact to the connected load (TCL). Value of maximum demand of a building and ratio of diversity factor must be goaded so as non overdesigned or under designed. By using MD also, many cost can be trim as cable size, the size of the breaker, busbar size etcBy cipher the TCL, it can know the total load connected for a particular area and also can determine the sizing of cables. But, the most most-valuable thing is by having the TCL, it can determine the MD. This MD ordain be declared to the utility program provider for the purpose of meter deposit and utility bill3.2.1 Diversity Factor (DF)Diversity factor is different or ratio between MD and TCL. the equation can relate MD, TCL to DF is MD = TCL x DFShould be reminded, to determined DF normally it can non be precisely determined. DF observe is only an approximate value only based on the guidance or previous data. The diversity factor is almost always greater than 1 since all components would have to be on at simultaneously at replete load for it to be one.3.2.2 amplification BurdenAfter MD known then it should be added 20% at DB and 30% in SSB or MSB to determine the size of the incoming breaker. This is because taking into account the improver in the load in the future. it is known as increase burden.The specification percent of increase burdenDistribution BoardSchool MD + 20% smear TCLHospital TCL + 20%Sub Switchboard and Main SwitchboardMD + 30%3.3 lap covering BreakerTo provided adequate over current protection, each circuit should be equipped with a circuit breaker for automatic unwrapion of supply in the blusht of overload current and erroneousness current. the circuit breaker installed in a circuit should break any fault current flux in the circuit breaker in front such current causes danger due to thermal or me chanical effect produced in the circuit or the associated connection. the characteristics of the breaker shall satisfy the condition that the breaking capacity should be greater than or equal to the potential lilliputian circuit current or public fault current at the point at which the breaker installedThe rated current of a circuit breaker is the current that it can carry continuously, generally for a length of more than eight hours. The rated current must not cause a temperature is between -5C to 40C. Different temperature rise limits are specified for different parts of a circuit breaker. A circuit breaker will not operate (Trip) if the current passing through it is 105% to 113% of its rated current. It will take one or two hours to trip if the current passing through it is 130% to 145% of the rated current.3.4 Type of rotary Breaker need to be determined3.4.1 Miniature Circuit Breaker(MCB)MCB are used extensively for the protection of final circuit in domestic and commercia l installations. they offer these circuit protection, particularly when overload or short circuit conditions are universe considered than the fuse alternatives.MCBs are available for both single phase and trine phase circuit. In a single phase circuit, a single MCB may be used in the live conductor or a two-pole MCB connected in the live and natural conductor. iii or four pole MCBs are used for protection in three phase supplies. If a fault current flow through even one pole of an MCB, all the three poles will be operated.The main standard for MCBs in BS 3871. This standard covers MCB ratings up to 100A, breaking capacities up to 9 kA and voltage ratings up to 415VThe preferred value of the rated current are 6, 8, 10, 13, 16, 20, 25, 32, 40, 50, 63, 80, 100, and 125AInstead of specifying the breaking capacity, the standard specifies the value of the short circuit capacity. the short circuit capacity refers to the prospective current expressed by its r.m.s value which the MCB is d esigned to make (closed), to carry for its operate time and to break under the specified conditions. the standard value of rated short circuit are 1.5, 3, 4.5, 6 and 10kA. for values in a higher place 10kA up to and including 25kA, the preferred value 20kA3.4.2 Moulded Case Circuit Breaker(MCCB)Moulded case circuit breaker(MCCB) are required for installation which have higher fault level or higher current ratings exceeding 125A. MCCBs have several advantages over ordinary switches and fuses in the control and protection of circuit and apparatus. they have a repeatable non-destructive performance and are safe in operation under fault conditions. it has built-in implement to simultaneously rude all three phases for a single phase fault.These circuit breaker are mainly used to protect main feeder cables, for incoming supply to sub circuit/distribution boards and for large motor circuit. for installation, MCCBs are suitable as free standing units, or for building into twinge cubic- type switchboards. Auxiliary items such as shunt trio elements, status switches, interlocks and motor-operated mechanism for remote operating can all be integrated into the MCCB.The main industrial standard for MCCBs are BS EN 60947-1 and BS EN 60947-2. these two standard define the characteristics, conditions for operation, orders for testing and the requirements for circuit breaker with rated voltages up to and including 1000V a.c or 1500 d.c.As there are no other standard values specified in BS EN 60947, the followings are some typical technical data for reference Current rating 10, 16, 20, 32, 40, 50, 63, 80, 100, 200, 300, 400, 630, 800, 1250ARated voltage 380, 400, 415VRated breaking capacity 10, 20, 25, 35, 65, 85kA(r.m.s)Rated making capacity 17, 44, 53, 63, 84, 143kA(peak)One minutes powerfrequency withstand voltage 2.5kV3.4.3 Residual Current-operated Circuit Breaker(RCCB)The Residual Current-operated Circuit Breaker(RCCB) are primarily designed to protect agains t indirect connection electric shock. The term indirect contact refers to the contact of the supply voltage indirectly through the touching of the exposed-conductive-part such as the metalic enclosures of electrical appliances, the metallic conduit, trunking or cable tray.These exposed-conductive-part are insulated from the live conductor and are connected to the earthing terminal and thus, should be at the earth potential. However, during an earth faults, as there is an earth fault current flowing from the love conductor through the exposed-conductive-part to the earth, the exposed metalwork may be at high potential relative to earth. touching the exposed- conductive-parts at this instance may cause an electric shock if its potential to earth exceeds 50V. Furthermore, id it is a high impedance earth fault, the magnitude of the earth fault current may not detonate the overcurrent protective device. Thus, a current will continue to flow to earth, maybe generating heat and causing fire. RCCB is designed to detect such a end current (ie. earth leakage current), to compare it to reference value and to spread out the protected circuit when the residual current exceeds this reference value.RCCBs are not designed to have a high breaking capacity and in fact, they have only a limited breaking capacity. They are therefore, not a replacement for other overcurrent protective devices which are designed to interrupt high fault current. There are four standard for RCCBs namely, BS4293, IEC 755, IEC 1008- 1 and Singapore standard SS 97.Based on IEC 1008, RCCBs are specified as followsPreferred rated voltage single phase, phase to neutral 230Vthree phase, three wire 400V three phase, 4 wire 400VPreferred rated current, IN 10, 13, 16, 20, 25, 32, 40, 63, 80, 100, 125ARated residual operatingcurrent,IN 0.006, 0.01, 0.03, 0.1, 0.3, 0.5AStandard value of residual nonoperating current 0.5 INminimum value of the ratedmaking and breaking capacity 10 IN or 500A whichever i s greaterRated condition short circuitcurrent 3, 4.5, 6, 10, 20kAMaximum break time 0.3s for residual current equal to 0.5 IN 0.15s for residual current equal to 20.5 IN 0.04s for residual current equal to 50.5 IN0.004s for residual current to 500A4.0 Voltage DropVoltage drop difference in voltage from one point in a current path to any other point in the same current path. Voltage drop is the result that happens to a voltage value when it meets with resistance in any current path while current is flowing, it only happens when flowing current meets resistance in a current path, the higher the value of current flowing, the higher the voltage drop across any conductor, connection, or contact in the current path.Based on Ohms law it takes one volt to push one amp through one ohm of resistance. The location of a voltage drop in a match circuit determines the shine it will have on the loads that are in parallel. When a voltage drop occurs before, or ahead of the farthermost parallel link in a parallel circuit, it will provide less than source voltage to all loads in parallel beyond the last parallel splice. When a voltage drop occurs after the last parallel splice in a parallel circuit, the same value of voltage drop has an identical affect on the load in the moved(p) branch whether it appears on the voltage feed side, or on the ground side of the branch load.When current flows through the cable, the voltage drop will result. This is based on a formula V = I x R I = current flows through the cableR = Resistance of the cableBased on requirement of IEE wiring regulation 525-01-01. The voltage drop between the origin of the installation (usually the supply terminals) and terminals of the fixed current using equipment does not exceed 4% of the nominal voltage of the supply.The voltage drop for building must make sure it not more than 4% depend to nominal voltage, where 4% of 1 = 4% of 240 V= 9.6 Volt4% of 3 = 4% of 415 V= 16.6 VoltThe voltage drop for outside building, must not exceed 20V from nominal voltage4.1 The Voltage Drop is Closely Related with Size of wrinkle closely circuits in a house do not have enough current or length to produce a high voltage drop. In the case of very long circuits, for example, connecting a home to a separate building on the same property, it may be infallible to increase the size of conductors over the minimum requirement for the circuit current rating. Heavily-loaded circuits may also require a cable size increase to meet voltage drop requirements in wiring regulations.Voltage drop and size cable can related with equation VD Total of voltage dropVd Voltage drop on cable mV/A/mIn Rated current of breaker (A)L Length of Cable (meter)5.0 CableIn electrical engineering cables are used to carry electric currents. Cables are the mean by which electrical energy is distributed from its source to its point of use. Copper wires in a cable may be bare, or they may be plated with a thin layer of another met al, most often tin but sometimes gold, silver or some other material. Tin, gold, and silver are some(prenominal) less prone to oxidation than copper, which may lengthen wire life, and makes solder easier.http//www.electronicsteacher.com/direct-current/dc-metering-circuits/00376.png5.1 InsulationThe insulation surrounds each conductor to prevent direct contact between individual conductors and earth. Type of insulation will depends on the voltage, the operating temperature of the conductor and the mechanical and environmental condition affecting the cable during both installation and operation. Type of insulation materialPolyvinyl chloride ( polyvinyl chloride)RubberCross-linked polyethylene (XLPE) pulverized mineralOil impregnated paper tapes5.2 Type of conductorPVC, PVC/PVCXLPE, XLPE/PVC (25 mm2)PVC/SWA/PVCXLPE/SWA/PVC (25 mm2)Fire Rated CableMIMS (mineral Insulated Mineral Sheathed Copper Conductor)MICC (Mineral Insulated Copper Clad Copper Conductor)5.3 Installation methodGI Co nduit PVCGalvanised/H.D.G. Trunking PVCHot Dipped Galvanised Perforated Cable Tray PVC/PVC, XLPE/PVC, PVC/SWA/PVC, XLPE/SWA/PVCHot Dipped Galvanised Cable bunk PVC/PVC, XLPE/PVC, PVC/SWA/PVC, XLPE/SWA/PVC5.4 Cable type and selectionThe current carrying capacity of a cable must be sufficient to supply for the maximum sustained current which will normally flow through it. The insulation must be adequate to deal with the voltage of the system and must not be damaged by the heat produced by the current flow, high ambient temperature or by heat transferred. Cable selection therefore is primarily related to the size of the cable which will carry the required current without the temperature of the surrounding insulation rising above a critical level which will result in the sectionalization of the insulation.5.5 Current rating of cableThe current rating of cable is determined by a number of factorsAmbient temperatureMaximum allowable conductor temperatureConductor material insulatio n materialInstallation method5.6 get wind the Size cableThe proper sizing of an electrical (load bearing) cable is important to ensure that the cable canOperate continuously under full load without being damagedWithstand the worst short circuits currents flowing through the cableProvide the load with a suitable voltage (and avoid excessive voltage drops)(optional) Ensure operation of protective devices during an earth faultSelected the size cable can base on In IbIz InIz In Ib* In rated currentIz rated current of cableIb design current