PCB HV spacing

[Paul W.]

Hi,

I've seen some PCB's that route a slot in between two high voltage
terminals. Does the air spacing provide a better dialetric limit as
compared to the traces spacing over the surface of an FR4 PCB with
solder mask?

I would have thought it would have been better to have the FR4
material between the two points, or does it really matter if its over
a surface?

Thanks.

 

[Joerg]

Paul, one concern with HV between traces is contamination. A tiny film of
dirt can cause a pretty dazzling fireworks. Air might be better if the
gap is large enough so no dust can lodge in there.

Regards, Joerg.

"Paul W." wrote:

Hi,

I've seen some PCB's that route a slot in between two high voltage
terminals. Does the air spacing provide a better dialetric limit as
compared to the traces spacing over the surface of an FR4 PCB with
solder mask?

I would have thought it would have been better to have the FR4
material between the two points, or does it really matter if its over
a surface?

Thanks.

 

[Joerg]

Paul, just as an example from the med electronic side: The regs require a
creepage barrier (meaning across a surface) to be almost twice as wide as
an air gap for the same voltage.

Regards, Joerg.