How to compute minimum bend radious of NM wire?
The rule for nm is NEC 334.24 bends in nm and nmc shall be made so the cable will not be damaged. The radius of the curve of the inner edge of any bending during or after install shall not be less than 5 times the diameter of the cable.
The diameter is the thickest area in the direction of the bend (this is different than “fill” where the widest point of the cable is the diameter)
The difference becomes a big deal with flat and under carpet forms of nm.
NM requires the sheath to enter the box 1/4”  beyond the clamp NEC 314.17 so the sheath can not be removed until Inside the box.