Live-Line (Energized) Work and Rubber Glove Procedures
This domain tests the methods and equipment that let you work on energized conductors safely: hot stick, rubber glove and barehand techniques, insulating cover-up, and the inspection, testing and storage routine behind every piece of insulating equipment. Expect glove classes and maximum use voltages, hot stick care, cover-up sequencing, minimum approach distances and insulated aerial device testing.
Gloves and sleeves
- Rubber glove classes and maximum AC use voltages: Class 00 at 500 V, Class 0 at 1,000 V, Class 1 at 7,500 V, Class 2 at 17,000 V, Class 3 at 26,500 V and Class 4 at 36,000 V.
- Inspect before every use: visual check, then an air test by rolling the glove cuff to inflate and listening and feeling for leaks.
- Leather protectors go over the rubber glove to resist mechanical damage; sleeves are worn when the arm enters the minimum approach distance.
- Store gloves in a canvas bag away from heat, sunlight, oil and ozone; in-service gloves are dielectric tested at intervals set by the utility, commonly every six months.
Hot sticks and cover-up
- Live-line tools are kept clean, waxed and dry, stored where they cannot absorb moisture, and dielectrically tested on a scheduled interval; never lay one on the ground or use it as a lever.
- Cover-up (line hose, blankets, gutter, insulator hoods) is applied so no energized surface is left exposed next to the work, starting with the closest conductor and grounded surfaces, and removed in reverse order.
- Insulated aerial devices, bucket liners and blankets carry periodic dielectric tests; the boom leakage current test is part of the annual routine.
Worked example
A crew will glove a 25 kV circuit on a four-wire grounded wye system. Line-to-neutral voltage is 25 ÷ 1.732 = 14.4 kV, so Class 2 gloves (17 kV maximum use) are required. Class 1 gloves at 7.5 kV are inadequate even though the phase-to-phase voltage is the number usually quoted. The reasoning: rubber glove work exposes the worker to phase-to-ground voltage, and the glove class must exceed that value.
Traps that cost marks
Wearing rubber gloves without leather protectors; using gloves near their maximum voltage with no margin; assuming a hot stick is fine because it looks clean; and leaving cover-up in place while working on the wrong side of it.