Solder resist breakdown voltage

[sh-eda]

Hi
I wonder if someone could help with this question.
What is the breakdown voltage of solder resist. I have seen a value of 500V-1000V/mil.
So can solder resist be relied on to reduce the track distance between 240V mains live, neutral and earth.
If so what would be the minimum track distances for 240 main with solder resist or does it have to be assumed to be the same as bare board, which is what I have always assumed.

Thanks.

 

[marce]

NO, solder resist is not a conformal coating, use bare board. To reduce the spacing you have to have a conformal coating and inspection procedures etc. Don't forget the devices legs have to be covered as well, in fact any exposed metal must be covered if it is going to be at mains potential.

 

[sh-eda]

Thanks for answering
Yes, this is what I thought. I read a paper which suggested otherwise which is why I asked.

 

[ArticCynda]

I read a paper which suggested otherwise which is why I asked.

As the name suggests, the primary purpose of a solder mask is to ensure solder only sticks to pads during wave soldering, and to lower the chance of solder bridges between adjacent pads. Their chemical structure is optimized to be heat resistant, not providing electrical isolation.

 

[sh-eda]

Thanks. that's what I thought.