Hi gb

St. Louis County, MO (and several municipalities within same) is who
charges additional permit fees for each pull box affixed to the studs
or otherwise properly mounted.

The wiring codes are vastly different for residential, commercial,
schools, hospitals, etc. I know of NO allowance for Romex in any
structure other than residential and even in residential usage,
conduit is still required in several areas.

If I recall correctly, regarding Romex A staple is required within 6
inches of a plastic pull box or 14 inches of a clamped metal pull box.
Some inspectors (whether code or not) will require a staple on ALL
wiring within 6 inches of the pull box, regardless of what kind of
wiring it is. Of course, you know how some inspectors are royal
PITA's.

It's been over 30 years since I worked my way up the ranks and roughly
10 years since I worked in the field. And even then I only worked in
residential. Everything since then was just predication work.

TTUL
Gary