Sometimes, you may be confused when looking for information about the electrical operating voltage for personal or system protection. In general, the minimum insulation distance of the device provides the best information for protection, especially in the event of a device failure. Proper clearance and creepage distances help determine the rated voltage.
Hirose HRS Molex-JAE-JST Tyco HARTING Domestic Spot Inventory Manager Liu Peng69331
Clearance
Clearance refers to the shortest distance between two conductive elements to pass through air.
Let's take Harting's material (part number 09031966921) as an example to explain this problem one by one.
To determine the clearance distance.
Determine the installation category.
Determine the expected level of contamination.
Select the rated impact withstand pressure from Table 1.
Select the minimum clearance required from Table 2.
Creepage distance
Creepage distance refers to the shortest distance between two conductive elements on the surface of an insulating material.
Creepage distance is to be determined.
Determine the installation category.
Determine the expected level of contamination.
Depending on the nominal voltage and the type of power supply system, select the rated voltage from Table 3.
For the length of the creepage distance, the tracking form of the insulating material must be considered. If there are no more notes, the CTI value of the insulation should be < 400 and the isolation group should be III A B.
cti(Relative tracking index).
This index indicates the conductivity of the insulating material and affects the specified creepage distance. The effect of the CTI value on the creepage distance is as follows:
The higher the exponential value, the shorter the creepage distance.
Plastics can be divided into insulation groups according to CTI.
Example calculations. What voltage should be used if the creepage distance, insulation category, degree of contamination is known:
Hirose HRS Molex-JAE-JST Tyco HARTING Domestic Spot Inventory Manager Liu Peng69331image735×213 5.13 kb
How to determine the voltage rating
Define the installation category.
Determine the expected level of contamination.
Select the rated impact withstand voltage (in kv) from Table 2
Select the phase of the voltage to ground derived from the rated system voltage in Table 1.
Select the voltage rating from Table 4.
Determine the number of phases and if Table 3 is relevant for the application.
Select the nominal voltage of the power supply system from Table 3.
Select the lower voltage from steps 4 to 7 above.
Table 1
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Table 2
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Table 3 Single-phase, three-wire or two-wire AC or DC systems.
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Three-phase, four-wire or three-wire AC systems.
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TABLE 4
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For example, what is the voltage rating of the 09031966921 connector harting?
09031966921 is rated at 50V under normal use because:
1.2mm creepage distance.
The installation type is II
The level of contamination is 2
Quarantine Group III A B
The CTI value < 400
For more information on creepage distances and clearances, please refer to Harting's operating instructions for voltage - creepage and clearance (002).pdf 9 (274.2 kb)
Hirose HRS Molex-JAE-JST Tyco HARTING Domestic Spot Inventory Manager Liu Peng69331