The Klein Tools Insulated Box End Wrench Set, 8-Piece (47140INS) is a set of insulated SAE box end wrenches built for utility linemen and electrical workers on energized equipment. This is an insulated wrench set designed for tightening and loosening bolts and nuts during live-line work up to 1000V, where tool failure is not an option. The set covers the eight sizes Klein identifies as the most commonly used for utility tasks: 3/8", 7/16", 1/2", 9/16", 5/8", 11/16", 3/4" and 13/16".

The insulation is the reason to buy this set. Each wrench carries ASTM F1505 certified three-part insulation, and a white wear-indication layer sits beneath the outer layer. When white shows through, the insulation has been compromised and the wrench should be replaced. That takes the guesswork out of tool inspections before the crew goes up.

Handles are oversized on purpose. Working in Class 2 rubber gloves makes a standard wrench handle hard to control, so Klein built these handles bigger for grip and added torque on heavy infrastructure tasks. The stepped-down box end design gives better access to nuts surrounded by hardware, brackets and crossarms.

The wrenches are steel with an overmolded plastic insulation system, and they pack into a foam-lined, heavy-duty carrying case that keeps them protected and organized between jobs. The case measures 15" x 11" x 3" (38.1 x 27.9 x 7.6 cm), and the full set weighs 6.4 lb (2.9 kg).

Who should buy it: utility linemen, substation and distribution crews, and electrical contractors who perform energized work and need certified insulated wrenches in the most common SAE sizes.

Insulated Wrenches Made for the Lineman's Glove

The Klein Tools Insulated Box End Wrench Set (47140INS) puts eight common SAE sizes, 1000V-rated insulation and a visible wear indicator in one protected case.

• Who it's for: Utility linemen and electrical crews who work energized equipment up to 1000V.
• Why it stands out: Oversized handles for Class 2 gloves, stepped box ends for tight hardware and a built-in wear indicator.
• Worth knowing: This is an SAE-only set, 3/8" through 13/16". Inspect the insulation before every use.

• What voltage is the Klein 47140INS rated for? Live-line work up to 1000V, with ASTM F1505 certified three-part insulation.
• What sizes are included? 3/8", 7/16", 1/2", 9/16", 5/8", 11/16", 3/4" and 13/16".
• How do I know when to replace a wrench? A white wear-indication layer shows through when the insulation is worn.
• Does it come with a case? Yes. A foam-lined, heavy-duty carrying case is included.