Howdy. I'm gonna straight up lay it out that I'm not an electrician, I AM an extra class amateur radio operator and have worked on higher voltage devices from 800 to 14 KV (tube amps and oscilloscopes). I've also done my own minor electrical work at home. That being said, I'm planning on installing a SPD at my home and have noticed that none of the manufacturers installation guides address flush installation. What I have seen of the two devices I'm looking at is that the Square D flush kit is a trim ring, and Eaton kit is a plastic cut in box. Id rather at least have the cut in box vs a device in the wall with no protection at all from a catastrophic failure. Are those really supposed to be installed in a metal sub panel?
