For high-voltage linemen and substation technicians, the rubber insulating glove is the single most critical piece of life-support equipment they own. These gloves-typically Class 2, rated for 17,000 volts, or Class 4, rated for 36,000 volts-are marvels of engineering. They are made from incredibly pure, dense natural rubber. But that rubber has two lethal, chemical enemies that are routinely mishandled in the field: ozone, and the worker's own hands.
Ozone (O3) is naturally present in the atmosphere, but its concentration spikes heavily around high-voltage equipment and during electrical storms. Ozone is violently reactive with natural rubber. It attacks the double bonds in the rubber's polymer chain, causing deep, jagged cracks that look like dried riverbeds-a condition called "ozone cutting" or "crazing." If a lineman wears a glove with an ozone crack, the high-voltage electricity will track directly through that compromised path to the hand, bypassing the insulation entirely.
The second enemy is mechanical folding. At the end of a shift, linemen often strip off their rubber gloves, roll them up like a burrito from the cuff to the fingertips, and stuff them into the leather protector gloves. This rolling creates severe, permanent creases at the joints of the fingers and thumbs. Under the stress of high voltage, these creased areas have reduced dielectric thickness and will fail instantly.
Rubber gloves must be stored flat, hung by the cuff on a wooden or plastic peg, or rolled gently *from the fingertips down to the cuff* (the opposite direction of putting them on) to prevent sharp creases.
Furthermore, the gloves must be protected from the corrosive oils and salts on the worker's own skin. After use, the inside of the rubber glove must be wiped out with a mild, pH-neutral soap and water, and allowed to air dry completely. Never use talcum powder inside the glove; it absorbs moisture and can actually hold corrosive sweat against the rubber. Before every single use, the worker must perform the mandatory "air test." They roll the cuff tightly to trap air, and squeeze the glove like a balloon, looking and listening for any microscopic pinhole leak. If even a tiny bubble of air escapes, the glove's dielectric integrity is shattered, and it must be immediately destroyed. A 17,000-volt glove is only as strong as its smallest unseen flaw.
