4kV high pot test
4kV high pot test
(OP)
Hi,
can anyone shed some light on this...what should be the minimum spacing between the +ve and -ve traces on a FR4 PCB, in order to pass in a 4kV high pot test.
Thanks!
can anyone shed some light on this...what should be the minimum spacing between the +ve and -ve traces on a FR4 PCB, in order to pass in a 4kV high pot test.
Thanks!
Best regards,
ct





RE: 4kV high pot test
RE: 4kV high pot test
I would 'guess' at a creepage distance in excess of 4mm.
RE: 4kV high pot test
Thanks for the reply. Or perhaps let me rephrase my question, say if I see the voltage breakage happen to a distance of 1mm for a given material at 1kV, would it be right to estimate (approximate) that when the distanec is 2mm, the breakage should then only happen at 2kV?
Thanks a lot.
Best regards,
ct
RE: 4kV high pot test
It also depends on air pressure. Google "Paschen curves".
For insulating materials, it somewhat follows a square root law, so 1 mm material might break down at 1 kV, but it could take 4 mm to withstand 2 kV...
According to NASA Technical Note D-7948, “inhomogeneity of leakage resistance within the body of the dielectric coupled with poor heat conductivity can produce high temperatures with attendant chemical changes. These changes can cause a decrease of resistivity by several decades of a portion of the material. The thickness of the dielectric is therefore effectively reduced and can lead to complete failure. This is the probable cause of the thickness effect-the variation of material dielectric strength with thickness in which the corona threshold voltage increases with dielectric thickness as expected, but the dielectric strength drops markedly.”
RE: 4kV high pot test
RE: 4kV high pot test
8.4 mm [0.33"] and 5,000 Vrms is 17.5mm [.69"]. Your case the spacing is between these two. The Hipot voltage
is determined usually by adding more voltage on top of
the normal voltage. For over 1kV, they add 1kV on top.
If you put 0.6 inch it'd probably be fine.
RE: 4kV high pot test