If you want to use the bigger boxes, go to a electrical supplier. They also make the covers that fit. You will be paying a small premium. You might also consider an http://www.homedepot.com/p/8-in-x-8-...04RC/100537130 I had to use one of these for my Basement master light switch install. I needed the size due to wire fill count. Also Stranded wire is much easier to fit in any box. It does cost more, but is definitely worth it for convenience. Dan