Pretty easy to install. Knock outs aren't really knock outs. I had to used my Greenlee KO set to punch the 3/4" hole I needed to add a LR conduit body into my main electric panel. There was plenty of space for #6 THHN inside. The only niggle was how the top lid and front cover are one piece, and I had to use shims behind the main box to float it off the wall so that the top cover can fit on. No biggie, but it could be better.