30 CFR § 18.40
Cable clamps and grips.
Insulated clamps shall be provided for all portable (trailing) cables to
prevent strain on the cable terminals of a machine. Also insulated clamps
shall be provided to prevent strain on both ends of each cable or cord
leading from a machine to a detached or separately mounted component. Cable
grips anchored to the cable may be used in lieu of insulated strain clamps.
Supporting clamps for cables used for wiring around machines shall be
provided in a manner acceptable to MSHA.
See MSHA's Program Policy Manual