Yes it’s in an enclosed metal box. Since it’s enclosed and the depth and width of the box are basically the same, there’s really no way to
Insulate that part.
Discussion
That's not true. You can wrap the outside or get a larger enclosure and insulate that. You could also get a heat tape to wrap around the inside of the box, which should give enough heat to keep it from freezing, but that would work better with insulation.