Ok, so I'm working on a new IGBT design with working voltage of 3200V.
I need some clarification on material group as mentioned on a few of the standards.
In determining creepage I need to know the material group, in my case there are no components on the PCB, so does this refer to the PCB as "material"?
If I then pick my boards CTI of 200 I'm in group IIIa, and my pollution degree is 2, this will then be having me using creepage of 32mm, which is insane unless I pass a test to be qualified as pollution degree I? Is this correct?
And I'm using:
UL_60950-1 Table 9 and Table 2N – Minimum creepage distances Continued
Material group classification Material group Comparative tracking index
CTI I 600 ≤
CTI II 400 ≤ CTI < 600
CTI IIIa 175 ≤ CTI < 400
CTI IIIb 100 ≤ CTI < 175
I need some clarification on material group as mentioned on a few of the standards.
In determining creepage I need to know the material group, in my case there are no components on the PCB, so does this refer to the PCB as "material"?
If I then pick my boards CTI of 200 I'm in group IIIa, and my pollution degree is 2, this will then be having me using creepage of 32mm, which is insane unless I pass a test to be qualified as pollution degree I? Is this correct?
And I'm using:
UL_60950-1 Table 9 and Table 2N – Minimum creepage distances Continued
Material group classification Material group Comparative tracking index
CTI I 600 ≤
CTI II 400 ≤ CTI < 600
CTI IIIa 175 ≤ CTI < 400
CTI IIIb 100 ≤ CTI < 175