What code?????? Please provide a link.

I've done the 4 pin mod to my 4kw spindle, I tapped a screw on spindle cover same as pics found with a search, you will find mine also. Like I posted I do not see a difference if I used my spindle mount that clamps around half my spindle.

This is certainly a option for the DIY hobbyist that's uncomfortable taking there new spindle apart and not having a ground at all.