Outdoor Rainproof Junction Boxes are very common in backyard electrical installations. Often times there are a lot of different conduits running in many directions and it makes sense to install a Junction Box (or Junction Can). These are NEMA 3 Rated, which is standard and rated for rainproof. They are not completely water tight for submerging in water. But under every day applications, including heavy rains, these work well.
One problem with them is that most electricians do not secure them properly. The National Electrical Code requires this box to have a mounting of some kind holding it in place, instead of just the array of conduits that junction into the box. If you look closely at the photo, you will see two (2) silver metal pipes in the rear of the Junction Box. Those are rigid metal conduit and driven into the ground and the Junction Box is attached to those. This keeps the box from moving or breaking loose.
