Junction box size - #2 xhhw/mhf to SER

[PCustoms]

What's wrong with it? The bushing even fits.

"Fits" is subjective. Maybe I'm wrong, but that doesn't look like it's made for SER...

 

[sparky 1971]

It's a cable clamp. All it has to do is fit snug enough the cable won't come out. Here is a 6/3 romex in a 3/4 clamp. Pretty much the same results.

 

[pattenp]

"Fits" is subjective. Maybe I'm wrong, but that doesn't look like it's made for SER...

It's a NM clamp, SER is a NM cable.