Line filter before or after trafo?

[jimk04]

So I was building myself a little linear psu for my Rpi music player. I have a Schurter pcb mount line filter and when came to wiring it together in realised i was about to solder it in after the 7vAC Talema.

Is this ok or does it need to be in front of it. I know that is is the norm for it to go first but thought I'd ask if it is ok after the trafo.

Thanks

 

[synonymous]

Before and close to chassis entry, earthed.

 

[JonSnell Electronic]

Line is mains input not after a transformer but before.
Always ensure it is properly earthed or it won't work at all because the RFI is dumped to the earth wire and if not connected, there is no where for it to go.

 

[DF96]

Some filtering can still take place without an earth wire: differential mode noise.

 

[phase]

Just to clarify, a common mode filter would be from one ac line to the other; no ground involved with that type of filter.

 

[jimk04]

Thanks for the replies.

The filter I have only has an earth on the load side. Just neutral and live on the line side.

But PE grounding to chassis is PE ground to chassis I guess so any earths would all be common to each other..so with 3 core mains in cable....only 2 cores to line side filter and the earth core to the middle pin of the load side and chassis.