Rated voltageVRated impulse voltageVOvervoltage categoryIIIIII<=50330500800>50 and <=15080015002500>150 and <=300150025004000Clause 29Clearances, Creepage distances and solid insulation爬电距离、电气间隙和绝缘穿通距离 (Table 1)2021/3/91 Minimum clearance (Table 2)Rated impulse voltageVMinimum clearancemm3300.55000.58000.515000.525001.540003.060005.580008.0100011.02021/3/92 How to find the minimum clearanceØHousehold appliance are in overvoltage category IIØSelect the rated voltageØUsing the table 1 to find out the rated impulse voltageØAccording to table 2, the minimum clearance could be found by rated impulse voltageThe clearances of four insulation types:1.Basic insulation2.Supplementary insulation3.Reinforced insulation4.Functional insulation2021/3/93 The clearance of basic insulationExample 1 : Water kettleRating : 220 – 240V 50Hz 2500 – 3000WRated voltageVRated impulse voltage (V)Overvoltage categoryIIIIII<=50330500800>150 and <=15080015002500>150 and <=300150025004000220 – 240VUsing category IIThe rated impulse voltage was 2500V2021/3/94 29.1.1 clearances of basic insulationRated impulse voltageVMinimum clearancemm3300.55000.58000.515000.525001.540003.060005.580008.0100011.0The minimum clearances of basic insulation was 1.5mm2021/3/95 Special components for basic insulation Ø The terminals of tubular sheathed heating elements counted 1mm, if the microenvironment is pollution degree 1.>1mmTubular sheathed heating elementPollution degree 12021/3/96 29.1.2 clearance of supplement insulationThe minimum clearance is same as the basic insulationThe distance between enclosure and internal wire2021/3/97 29.1.3 clearance of reinforced insulationThe reinforced insulation using the next step for rated impulse voltage. Between terminal and plastic enclosure2021/3/98 29.1.4 clearance of functional insulation Between terminalsThe functional insulation is between live parts of different potential2021/3/99 PTC Heating elementHair straighterPTC heaterHair straighter assembly2021/3/910 Different types of PTC Heating elements2021/3/911 Internal construction of PTC heating elementThe clearance between surfaces of PTC heating elements may be reduced to 1mmThe clearance >=1mmKapton filmPTC heating plateElectrode plate2021/3/912 29.2 creepage distancesStep 1 (To find out the pollution degree)ØPollution degree 2 applies unlessØPrecautions have been taken to protect the insulation, in which case pollution 1 appliesØThe insulation is subjected to conductive pollution, in which case pollution degree 3 appliesNote: The pollution degree should need refer to part 2. 2021/3/913 StandardPollution degree60335 – 2 – 3II60335 – 2 – 9III60335 – 2 –14III60335 – 2 –15 III60335 – 2 – 23 II60335 – 2 – 80 IIIPollution degree classification2021/3/914 §Tracking index (CTI) values§Material group I: 600<=CTI§Material group II: 400<=CTI§Material group III a: 175 <=CTI <400§Material group III b: 100 <=CTI<175Step 2 (To find out the material group)Tracking index tester2021/3/915 Tracking index (CTI) values2021/3/916 Minimum creepage distances for basic insulationWorking voltageVCreepage distance mmPollution degree123Material groupMaterial groupIIIIII a/bIIIIII a/b<=500.20.60.91.21.51.71.9ª>50 and <= 1250.30.81.11.51.92.12.4>125 and <=2501.61.31.82.53.23.64.0>250 and <= 4001.02.02.84.05.05.66.3>400 and <= 5001.32.53.65.06.37.18.0>500 and <= 8001.83.24.56.38.09.010.02021/3/917 The creepage of basic insulationExample 1: Water kettleRating : 220 – 240V 50Hz 2500 – 3000WØPollution degree 3 (refer to standard 60335 – 2 – 15 )The microenvironment is pollution degree 3 if the insulation can be polluted by condensation from steam produced during normal use of appliance. ØAssume the material group is III (the tighten grade)ØWorking voltage is between >125 and <=2502021/3/918 The creepage of basic insulationWorking voltageVCreepage distance mmPollution degree123Material groupMaterial groupIIIIII a/bIIIIII a/b<=500.20.60.91.21.51.71.9ª>50 and <= 1250.30.81.11.51.92.12.4>125 and <=2501.61.31.82.53.23.64.0>250 and <= 4001.02.02.84.05.05.66.3>400 and <= 5001.32.53.65.06.37.18.0>500 and <= 8001.83.24.56.38.09.010.02021/3/919 Working voltageVCreepage distance mmPollution degree123Material groupMaterial groupIIIIII a/bIIIIII a/b<=500.20.60.81.11.41.61.8ª>50 and <= 1250.30.71.01.41.82.02.2>125 and <=2500.41.01.42.02.52.83.2>250 and <= 4000.81.62.23.24.04.55.0>400 and <= 5001.02.02.84.05.05.66.3>500 and <= 8001.83.24.56.38.09.010.0Minimum creepage distances for functional insulation2021/3/920 Insulation typeDistanceBasic insulation4Supplementary insulation4Reinforced insulation8Functional insulation3.2Summary of Minimum creepage distances 2021/3/921 29.2.1 creepage for basic insulationLacquered conductors of windings1.5mmCreepage distance of winding need not be greater than the associated clearance specified in table 162021/3/922 Clause 29.2.2As per clause 29.2.2, the creepage distance of supplementary insulation shall not less than and 2.5mm.The internal wire of micro-switch was not securely fixed that it was possible to be touched by test finger with 2N force. The creepage distance were measured as 0mmInternal wire shall be access2021/3/923 Clause 29.2.3 The creepage distances of reinforced insulation shall not less than 8mm.As result, the creepage distance was measured 7.5mm between leads of neon lamp and the lamp cover joint. Leads of neon lampLensEnclosureLeon lamp leads2mm3mm2.5mThe creepage distances = 2.5+2+3 = 7.5mm2021/3/924 29.2.4 creepage distances of functional insulationCreepage distance betweenMeasured resultsLimitationSwitch terminals1.5mm2mm1.5mm2021/3/925 Clause 29.2.4Distance betweenMeasured resultsLimitationPCBBetween Point A and BClearanceCreepageClearanceCreepage2.07mm2.75mm1.5mm2.0mm2021/3/926 PCB TrackA BB AB A2021/3/927 29.2.4 creepage distance for function insulationCreepage distances may be reduced if the appliance complies with clause 19 with the functional insulation short-circuited. For example: Electronic component Electronic componentThe transistor leads < limitation of creepage distance 2021/3/928 Live PartSupplementary insulation (1mm)Basic insulation29.3.1 Material thickness requirement for supplementary insulation (1)Supplementary Insulation2021/3/929 Live PartReinforced insulation (2mm)29.3.1 Material thickness requirement for reinforced insulation (1)Reinforced Insulation2021/3/930 Live Part1st layer insulation2nd layer insulationEach of the layers should withstands the electric strength test for supplementary insulation 29.3.2 Material requirement for supplementary insulation (2)Basic insulation2021/3/931 29.3.2 Material requirement for reinforced insulation (2)Live Part1st layer insulation2nd layer insulation3rd layer insulationAny two layers together should withstands the electric strength test for reinforced insulation2021/3/932 < 1mmCase 1ClearanceCreepage distance2021/3/933 >= 1mmCase 2ClearanceCreepage distance2021/3/934 1mmCase 3ClearanceCreepage distancePath under consideration includes a V – shaped groove with internal angle of less than 80°and with a width greater than 1mm2021/3/935 Case 4ClearanceCreepage distance2021/3/936 Case 5ClearanceCreepage distance<1mm>1mm2021/3/937 谢谢 谢！谢！ 放映结束 感谢各位的批评指导！让我们共同进步2021/3/938 。