2.2 PPE, Rubber Glove Classes & Hearing Protection

Rubber Insulating Glove Classes (ASTM D120)

Rubber insulating gloves are specified by ASTM D120, Standard Specification for Rubber Insulating Gloves, and their in-service care is governed by ASTM F496. OSHA 29 CFR 1910.137 incorporates these standards by reference. Gloves are classified as Type I (non-ozone-resistant) or Type II (ozone-resistant) and are rated into six classes by maximum AC use voltage:

A common memory trap: the class number is not the voltage in kV. Class 1 is 7.5 kV, not 1 kV; Class 2 is 17 kV, not 2 kV. The numbers are simply sequential. Also note that the retest voltage is significantly higher than the maximum use voltage — this built-in margin ensures the glove can withstand transient overvoltages in service.

Leather Protectors

Rubber insulating gloves are easily damaged by abrasion, puncture, and cuts. Leather protector gloves are worn over the rubber gloves to provide mechanical protection. Protectors are required for all classes, with limited exceptions for Class 00 and Class 0 under specific short-task conditions where the protector would create a hazard (e.g., fine work). The leather protector must be the correct size so that the rubber glove's cuff extends beyond the protector cuff by at least the distance specified in ASTM F496 — typically 1 inch for Class 0 and larger amounts for higher classes — to prevent a flashover tracking from the protector to the worker's skin.

In-Service Care and Retest Intervals

Gloves and sleeves must be electrically proof-tested at intervals not exceeding those below, per OSHA 1910.137(b)(2)(ii) and ASTM F496:

A glove that has been tested but not issued for service may not be placed into service unless it has been electrically tested within the previous 12 months. So a spare glove sitting on the shelf for a year must be retested before use even if its 6-month in-service clock never started.

Before each use, the worker must perform a visual inspection and an air test (inflate the glove and roll the cuff to trap air, then squeeze and watch for leaks). Gloves that fail either check must be removed from service. Proof-test voltage is applied for at least 1 minute but no more than 3 minutes.

Arc-Rated Clothing

Arc-rated (AR) clothing is distinct from flame-resistant (FR) clothing. The arc rating (ATPV or EBT) is the incident energy in cal/cm² that the fabric can withstand with a 50% probability of the wearer sustaining a second-degree burn underneath. All AR clothing is FR, but not all FR clothing has an arc rating. NETA testing technicians working inside the arc-flash boundary must wear AR clothing matching the PPE category or incident energy analysis result (see Section 2.1).

Hearing Protection

OSHA's hearing conservation standard (29 CFR 1910.95) and NFPA 70E require hearing protection when noise exposure meets or exceeds 85 dBA time-weighted average (TWA) over an 8-hour shift. The Noise Reduction Rating (NRR) printed on a hearing protector estimates its attenuation under ideal laboratory conditions; field attenuation is typically less. Arc-blast events, switchgear operations, and air-blast circuit breaker operation can produce impulse noise well above 140 dB peak, so hearing protection inside the arc-flash boundary is mandatory regardless of the daily TWA.

Exam trap: Some study materials cite an older 90 dBA threshold. The action level for OSHA's hearing conservation program is 85 dBA TWA, with engineering controls required at 90 dBA. NFPA 70E aligns with the 85 dBA hearing-conservation trigger for PPE selection.

Field Inspection and Documentation

Before each shift, the technician inspects rubber gloves for pinholes, cuts, ozone checking (Type II gloves resist ozone cracking), and chemical contamination. Gloves are stored cuff-down in a protective bag or box when not in use, away from sunlight, heat, and ozone-producing equipment. Damaged gloves are tagged out of service and sent for retest or disposal. The retest date is marked on each glove, and a glove past its retest date must not be used until it passes a dielectric test. NETA companies typically maintain a glove log that records issue date, retest date, and the glove's serial number. On the exam, expect items that ask which class is required for a given voltage (e.g., Class 2 for 15 kV work, Class 3 for 25 kV) and the 6-month glove / 12-month sleeve retest interval — both are high-yield facts.