An adjustable loop clamp assembly provides improved retention of electrical cables, tubes or hoses. The clamp assembly comprises a flexible strap with first and second ends. A base, having an elevated platform, a lower platform, a midsection, and two side supports, receives a second end of the strap in an aperture of the midsection. The first strap end is securably affixed to the elevated platform of the base. Support holes in the side supports receive pin portions of a locking cam, the locking cam further comprising a handle portion and a cam portion. A mount bolt is receivable in alignable apertures of the lower platform and the handle portion. The pin portions of the locking cam are pivotably engaged into the mount holes of the side supports, allowing rotation of the locking cam into a position that engages the strap with the cam portion, locking the strap against the base structure, simultaneously contacting the handle portion against the lower platform, further aligning the mount holes in the handle portion and the lower platform so that when a mount bolt is passed through those holes and secured, the locking cam is prevented from disengagement.