Heavy Duty Kill A Watt Project Completed - see pix

yes it might fit an outlet box, but it is a bit deep/thick

Installation hole Size 76mm x 39mm , face 79 x 43 x 48mm Deep/thick

i was thinking of the an ammo box, remember got to get the "current transformer" in there too, although its not very big

maybe use a deep 4x4 or 6x6 box, although i like the narrow ammo box idea, deep sturdy, weather proof seal on the lid snap latch latch no screws, put rubber grommets around the 30amp cord going in and out of the box