6 Cables - InsulatorPrevent the physical contact: between two cables, cable-to-groundPhysical durable e.g. impact, heatChemical durable, e.g. erosionCommonly usedPolyvinyl Chloride (PVC)Cross linked Polyethylene (XLPE)
8 Cables for High Voltage Withstand the high voltage: insulator (if any) need to be good.Long distance transmission: Cable cost & Installation cost (e.g. electricity pole)Two main typesBare Wires (reduce cost)Insulated WiresComplication of Cable for High Voltage is the high voltage.
9 High Voltage Cables Bare Wires Made of Aluminum for lower costTransmission system (not distribution system for safety): Reduce usage: animals, accident, etc.AAC: All Aluminum CableAAAC: All Aluminum Alloy CableACSR: Aluminum Conductor Steel Reinforced
10 High Voltage Cables Bare Wires AAC: Basic type, for shorter spanAAAC: Improve the property of Aluminum by making it as an alloy stronger, larger span, corrosion resistance (e.g. sea)ACSR: Insert the steel in the core to have more tension.
11 High Voltage Cables Insulated Wires For safety and prevent interruptionPIC: Partial Insulated CableSAC: Space Aerial CableXLPE: Cross-linked Polyethylenehire-fire-crew-hot-air-balloonist_n_ html
12 High Voltage Cables Insulated Wires - PIC Should not have any directly contact to human.Extruded conductor shield is made of semi-conducting material to manage the electric field.Insulation only to protect line to line contact.
13 High Voltage Cables Insulated Wires - SAC Have extra shealth.Should not have any directly contact to human.
14 High Voltage Cables Insulated Wires - XLPE Conductor -> CopperConductor Shield -> made of semi-conducting material, allow the uniform distribution of electric field, prevent break downInsulationInsulation Shield -> made of semi-conducting material, to shield the electric fieldJacket / Shealth -> To protect the cableCan be used both in Air and underground (humidity)
15 Cables for Low Voltage Below 750V Conductor: Aluminum or Copper Insulator: PVC or XLPENumber of Conductor: 1 or manySpecial Type to suite the need: Fire Retardent
16 Cables for Low Voltage (see pdf) PVCNAY (aluminum)THWVAFVCTNYY (double shealth)XLPECVMIFire Safety CableFlame RetardantFire ResistantComplication of Cable for Low Voltage is the usage.MI Cable is very durable cable with metal shealth.Flame Retardant -> stop spread of fireFire Resistant -> can operate for a period of time
17 Cables for Low Voltage Fire Resistant Cable Flame RetardancyFlame PropagationAcid and Corrosive Gas EmissionSmoke EmissionFire Resistance (Circuit Integrity)
18 Cables for Low Voltage Fire Resistant Cable Fire Alarm SystemBuilding Automation SystemEmergency Lighting SystemPublic Address SystemStandby Power SystemComputer Network SystemClosed Circuit TV SystemElevators and Escalators SystemFire Pumps and Pressurized StairsEtc.
19 AssignmentsTake pictures of the cable that you can see and classify the types of those cables.Take pictures of the name-plates
20 Cable SelectionUsage: Table 5-16 (EIT Standard ) for low voltage cableRated Voltage: 300V or 750VRated CurrentMultiple ConductorsVoltage DropRated Voltage is straight forward: either 300V or 750V
21 Cable Selection – Rated Current Size of ConductorType of InsulatorAmbient TemperatureInstallation Conditions:Calculation: BCC - Technical_data_CableTable: BCC - InstallationGuide, AS_NZS_ _2009Rated Voltage is straight forward: either 300V or 750VLow voltage has so many possibility installation method.
28 Cable Selection – Rated Current Number of Cables in a Conduit Handout: BCC - Installation Guide.pdf
29 Cable Selection – Multiple Conductors To increase the rated currentHandout: BCC - Installation Guide.pdf
30 Cable Selection – Multiple Conductors Only for cable from 50 sq.mm. and upSame type of cablesSame lengthSame wiring method
31 Cable Selection – Voltage Drop Voltage drop due to the impedance of the cableNECMain incoming to load: no more than 5%Feeder: no more than 2%Branch Circuit: no more than 3%
32 Cable Selection – Voltage Drop ZcableZload220 V (AC)
33 Cable Selection – Voltage Drop Load: 𝑍 𝑙 is from the consumption and power factor: 𝑝𝑓= 𝑅 𝑙 𝑍 𝑙 or cos −1 𝑝𝑓 = 𝑅 𝑙 𝑍 𝑙Cable: 𝑍 𝑐 is from the table ( 𝑅 𝑐 and 𝑋 𝑐 )𝑋 𝑐 depends on the wiring configurations.
34 Cable Selection – Voltage Drop Calculation Use the normal voltage divider in the calculation.𝐸 𝑠𝑜𝑢𝑟𝑐𝑒 = 𝐸 𝑐 +𝐸 𝑙𝐸 𝑠𝑜𝑢𝑟𝑐𝑒 = 𝐼∗(𝑅 𝑐 + 𝑗𝑋 𝑐 ) +𝐸 𝑙????
35 Cable Selection – Voltage Drop Calculation visualisation_basse_def.pdf
36 Cable Selection – Rated Current Calculation visualisation_basse_def.pdf
38 Cable Selection – Rated Current From Table Voltage Drop/Amp/kmvisualisation_basse_def.pdf
39 Cable Selection – General Rules 20% to 25% factor.Using current or VA (not power).
40 Cable Selection – Examples Water Heater 6kWin Air or in Metal ConduitMicrowave 2,300VAIndustrial Heater 40kW, 400V 3phase40oC or 50oC6mm2 in Air and 10mm2 in Metal Conduit2.5mm225mm2 and 35mm2
41 Cable Selection – Examples Motor 37kW, 400V, In=72ADOL & Star-DeltaMotor 60kW, 400V, pf.=0.8Roomreceptacles 2.5kVAlighting 500VA6mm2 in Air and 10mm2 in Metal Conduit2.5mm225mm2 and 35mm235mm2 and 25mm2 (nominal current = nominal current (because of start-delta)/(root 3) and 6 wires is required reduction factor of 0.82)
43 Reference Electrical Systems Design: ประสิทธิ์ พิทยพัฒน์ Thai Electrical Code 2002: EIT StandardElectrical Installation Guide 2010: schneider-electricDepend on the area, end-user can connect to the “meter” of the authority in three ways.
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