Hi, I am designing a PCB in which there is 220V AC voltage involved which enters through the power inlet connector then this signal goes to SMPS from where this signal converts to 12V DC signal and then this signal converts to other required low voltage but the problem is that I don't have idea about the routing of AC voltage like how to give cut out and isolation from other low voltage please give me idea about this that would be highly appreciable thank you

 

Hi, I am designing a PCB in which there is 220V AC voltage involved which enters through the power inlet connector then this signal goes to SMPS from where this signal converts to 12V DC signal and then this signal converts to other required low voltage but the problem is that I don't have idea about the routing of AC voltage like how to give cut out and isolation from other low voltage please give me idea about this that would be highly appreciable thank you

If it is Class I then it has to be at least 3mm from any low-voltage tracks, if it is Class II then 5mm. (This varies with the tracking index of the pcb material and the "pollution degree" i.e. how much dirt is likely to accumulate on the pcb during its lifetime, and how conductive that dirt may be. You will find tables for all the distance in EN60335-1.
Make sure that it is fused for the current carrying capacity of the tracks.
If the incoming mains cable is soldered to the board then it needs additional mechanical support in case of breakage of the solder joint.

 

Hi.
Route them near an edge of board, away from any other traces, grouped with all AC components as fuses, chokes, transformers, transzorbs. Stay away from small signals traces. Etch warnings for that area.

 

If it is Class I then it has to be at least 3mm from any low-voltage tracks, if it is Class II then 5mm. (This varies with the tracking index of the pcb material and the "pollution degree" i.e. how much dirt is likely to accumulate on the pcb during its lifetime, and how conductive that dirt may be. You will find tables for all the distance in EN60335-1.
Make sure that it is fused for the current carrying capacity of the tracks.
If the incoming mains cable is soldered to the board then it needs additional mechanical support in case of breakage of the solder joint.

Thanks for the reply also how much the approximate trace thickness would be on PCB

 

Thanks for the reply also how much the approximate trace thickness would be on PCB

Did you get the freebie Digikey ruler?
If not then look at the very last section of the datasheet
https://mm.digikey.com/Volume0/opasdata/d220001/medias/docus/2116/PCB-RULER-12INCH_Rev_2016.pdf
It depends on the track thickness (usually 35μm) as well as width and your maximum permitted temperature rise.

 

Another method is learning by example. Borrow some scrap power supply PCboards and observe the spacings that are used for the mains level traces. This is in addition to the good advice posted so far. Failed product boards should be easy to get.

 

Another method is learning by example. Borrow some scrap power supply PCboards and observe the spacings that are used for the mains level traces. This is in addition to the good advice posted so far. Failed product boards should be easy to get.

Unless they are failed far-Eastern power supplies which have insufficient mains clearance/creepage!