关于爬电距离和空气间隙的标准

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Example 1 : Water kettle Rating : 220 – 240V 50Hz 2500 – 3000W Rated voltage V Rated impulse voltage (V) Overvoltage category I
<=50 >150 and <=150 >150 and <=300
<=50 >50 and <=150 >150 and <=300
330 800 1500
Minimum clearance (Table 2)
Rated impulse voltage V
330
Minimum clearance mm
0.5
500
800 1500 2500 4000 6000 8000 1000
Pollution degree classification Standard Pollution degree
60335 – 2 – 3 60335 – 2 – 9 II III
60335 – 2 –14
60335 – 2 –15 60335 – 2 – 23 60335 – 2 – 80
III
I
1
2
3
Material group
II III a/b
Material group
I II III a/b
<=50 >50 and <= 125 >125 and <=250 >250 and <= 400 >400 and <= 500 >500 and <= 800
0.2 0.3 1.6 1.0 1.3 1.8
0.2
0.3 1.6 1.0 1.3 1.8
0.6
0.8 1.3 2.0 2.5 3.2
0.9
1.1 1.8 2.8 3.6 4.5
1.2
1.5 2.5 4.0 5.0 6.3
1.5
1.9 3.2 5.0 6.3 8.0
1.7
2.1 3.6 5.6 7.1 9.0
1.9ª
2.4 4.0 6.3 8.0 10.0
1.1 1.4 2.0 3.2 4.0 6.3
1.4 1.8 2.5 4.0 5.0 8.0
1.6 2.0 2.8 4.5 5.6 9.0
1.8ª 2.2 3.2 5.0 6.3 10.0
Summary of Minimum creepage distances
Insulation type Basic insulation Supplementary insulation Distance 4 4
The clearance >=1mm
Kapton film
Electrode plate
PTC heating plate
The clearance between surfaces of PTC heating elements may be reduced to 1mm
29.2 creepage distances
The clearances of four insulation types:
1. 2. 3. 4. Basic insulation Supplementary insulation Reinforced insulation Functional insulation
The clearance of basic insulation
Reinforced insulation
Functional insulation
8
3.2
29.2.1 creepage for basic insulation Lacquered conductors of windings
1.5mm
Creepage distance of winding need not be greater than the associated clearance specified in table 16
II 500 1500
2500
III 800 2500 4000
Using category II
330 800 1500
220 – 240V
The rated impulse voltБайду номын сангаасge was 2500V
29.1.1 clearances of basic insulation
Rated impulse voltage V Minimum clearance mm
29.1.2 clearance of supplement insulation
The minimum clearance is same as the basic insulation
The distance between enclosure and internal wire
29.1.3 clearance of reinforced The reinforced insulation insulation using the next step for rated impulse
330 500 800
The minimum clearances of basic insulation was 1.5mm
0.5 0.5 0.5 0.5 1.5 3.0 5.5 8.0 11.0
1500 2500 4000 6000 8000 1000
Special components for basic insulation
III II III
Step 2 (To find out the material group)
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<175
Clause 29Clearances, Creepage distances and solid insulation爬电距离、电
气间隙和绝缘穿通距离 (Table 1)
Rated voltage V
Rated impulse voltage V Overvoltage category I II 500 1500 2500 III 800 2500 4000
Clause 29.2.2
As 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 0mm
Step 1 (To find out the pollution degree)
Pollution degree 2 applies unless Precautions have been taken to protect the insulation, in which case pollution 1 applies The insulation is subjected to conductive pollution, in which case pollution degree 3 applies Note: The pollution degree should need refer to part 2.
The creepage of basic insulation
Creepage distance mm
Pollution degree
Working voltage V
I
1
2 Material group
II III a/b
3 Material group
I II III a/b
<=50
>50 and <= 125 >125 and <=250 >250 and <= 400 >400 and <= 500 >500 and <= 800
The
terminals of tubular sheathed heating elements counted 1mm, if the microenvironment is pollution degree 1.
>1mm
Tubular sheathed heating element
Pollution degree 1
I II III a/b
<=50 >50 and <= 125 >125 and <=250 >250 and <= 400 >400 and <= 500 >500 and <= 800
0.2 0.3 0.4 0.8 1.0 1.8
0.6 0.7 1.0 1.6 2.0 3.2
0.8 1.0 1.4 2.2 2.8 4.5
PTC Heating element
Hair straighter PTC heater
Hair straighter assembly
Different types of PTC Heating elements
Internal construction of PTC heating element
0.6 0.8 1.3 2.0 2.5 3.2
0.9 1.1 1.8 2.8 3.6 4.5
1.2 1.5 2.5 4.0 5.0 6.3
1.5 1.9 3.2 5.0 6.3 8.0
1.7 2.1 3.6 5.6 7.1 9.0
1.9ª 2.4 4.0 6.3 8.0 10.0
The creepage of basic insulation
Tracking index tester
Tracking index (CTI) values
Minimum creepage distances for basic insulation
Creepage distance mm
Pollution degree
Working voltage V
voltage.
Between terminal and plastic enclosure
29.1.4 clearance of functional insulation
Between terminals
The functional insulation is between live parts of different potential
Minimum creepage distances for functional insulation
Creepage distance mm Pollution degree Working voltage V
I
1
2 Material group
II III a/b
3 Material group
Example 1: Water kettle Rating : 220 – 240V 50Hz 2500 – 3000W
Pollution 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. Assume the material group is III (the tighten grade) Working voltage is between >125 and <=250
0.5
0.5 0.5 1.5 3.0 5.5 8.0 11.0
How to find the minimum clearance
Household appliance are in overvoltage category II Select the rated voltage Using the table 1 to find out the rated impulse voltage According to table 2, the minimum clearance could be found by rated impulse voltage
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