grounding metalwork for EMC

[Simon]

We are in a conundrum as to how to ground our metalwork. Much of it is just framework and some is enclosures for electronic items. With every part coated nothing is electrically connected so we would have to pick which items need bonding together and then to vehicle chassis. The whole bonding to a chassis has always confused me as if the vehicle body is a Faraday cage why worry?

[ocset]

You definetely need to  electrically ground your circuits to vehical chassis. -And this is for electrical noise reduction (EMI reduction). You will often find that you can  sometimes pass EMC tests by grounding to the chassis at a slightly different point.........but this is often by trial and error, its very difficult to actually calculate to exactly where on the chassis you have to connect ground  in order to get the best EMC test results...its all like microwave engineering

[Simon]

its all like microwave engineering

Yea, and we are metal bashers