What are the ASTM D120 rubber insulating glove classes and their voltage ratings?

ASTM D120 (Standard Specification for Rubber Insulating Gloves) defines six classes of rubber insulating (dielectric) gloves. Each class has a proof-test voltage (the voltage applied during acceptance testing to verify insulating integrity) and a maximum use voltage (the highest voltage the glove may be used on during live electrical work). The classes are: Class 00: proof test voltage 2500V AC, maximum use voltage 500V AC / 750V DC. Color code: beige (tan). Use case: low-voltage electrical work, telecom, 120V–480V systems. Class 0: proof test voltage 5000V AC, maximum use voltage 1000V AC / 1500V DC. Color code: red. Use case: 480V–1000V systems, residential and light commercial electrical. Class 1: proof test voltage 10000V AC, maximum use voltage 7500V AC / 11250V DC. Color code: white. Use case: medium voltage systems up to 7.5 kV, utility distribution work. Class 2: proof test voltage 20000V AC, maximum use voltage 17000V AC / 25500V DC. Color code: yellow. Use case: high-voltage transmission and distribution, 15kV class equipment. Class 3: proof test voltage 30000V AC, maximum use voltage 26500V AC / 39750V DC. Color code: green. Use case: very high voltage utility transmission work. Class 4: proof test voltage 40000V AC, maximum use voltage 36000V AC / 54000V DC. Color code: orange. Use case: highest-voltage transmission work. The class number does NOT represent the voltage in any direct numerical way — Class 2 provides 17000V protection, not 2000V. The color coding is a required field under ASTM D120 and OSHA 1910.137 to prevent mistaken use of a lower-class glove on higher-voltage systems. Encode glove.insulating_class as the class designation ('00', '0', '1', '2', '3', '4') and glove.max_use_voltage_ac_v as the numeric maximum use voltage (500, 1000, 7500, 17000, 26500, 36000).

Why are leather protectors required over rubber insulating gloves, and when are they not required?

OSHA 1910.137(c)(2)(ix) and ASTM F496 (Standard for In-Service Care of Insulating Gloves and Sleeves) require leather protectors to be worn over rubber insulating gloves in most live electrical work applications. The leather protector requirement exists because: Rubber insulating gloves are made of natural or synthetic rubber — the electrical insulating material is also physically vulnerable to puncture by wire insulation ends, metal burrs, screw threads, and tool edges. A pinhole or cut in the rubber glove from mechanical contact would compromise the electrical insulation without being immediately visible to the worker. The leather protector absorbs the mechanical stress of tool use and contact with sharp conductors, protecting the rubber glove's insulating integrity. Leather protectors themselves are not electrically insulating — they are mechanical protection only. When leather protectors may be omitted (OSHA 1910.137(c)(2)(ix) exception): where leather protectors would interfere with the fine manipulation required for the specific task, leather protectors may be omitted provided the employer can demonstrate that the risk of the gloves being damaged by the task is acceptably low. This exception requires specific employer authorization and is task-specific — it is not a blanket exemption. In practice, leather protectors are required for most utility and industrial electrical work. For precision electronic work at lower voltages (Class 00, Class 0) where fine finger dexterity is essential, some employers permit leather protector omission for specific tasks with documented risk assessment. Encode glove.requires_leather_protector as 'yes' for all rubber insulating gloves — the default requirement is leather protectors; exceptions are employer-authorized exceptions, not product-level characteristics.

What is the 6-month retest requirement for rubber insulating gloves, and what does retest involve?

OSHA 1910.137(b)(2)(ii) requires that rubber insulating gloves that have been used in service be electrically retested every 6 months to verify that insulating integrity has not been compromised during use. The retest is performed by a qualified testing laboratory using the same proof-test voltage specified in ASTM D120 for the glove's class. Retest procedure: the gloves are filled with water and immersed in a water bath. High voltage is applied between the water inside the glove and the water outside. The test current is monitored — a glove that passes allows only the expected leakage current; a glove with a pinhole, crack, or deteriorated insulation will show elevated leakage current and fail. Passed gloves are marked with the test date (typically a color-coded date stamp or sticker applied by the testing lab). A glove removed from service (stored without use) does not need retest during storage — the 6-month clock restarts when the glove is returned to service. A glove that has been exposed to any electrical incident (arcing, voltage exceeding its class rating) must be removed from service immediately and retested before reuse, regardless of time since last test. Encode glove.test_date as the date of last retest in ISO format (YYYY-MM-DD). AI agents should surface the test_date to buyers — a glove with test_date more than 6 months before the expected use date requires a new test before it can be legally used. Encode glove.retest_due_date as the date when retest becomes required (test_date + 6 months) to enable automated compliance alerting.

What do Type I and Type II designations mean for rubber insulating gloves?

ASTM D120 specifies two glove types based on the rubber compound used: Type I (natural rubber): made from natural rubber (latex). Natural rubber provides excellent electrical insulation and good flexibility at low temperatures. However, natural rubber is susceptible to degradation by ozone, UV light, petroleum-based products (oils, fuels), and some solvents. Type I gloves should not be used where they will contact oil or petroleum-based substances. Natural rubber also poses a latex allergy risk for workers with latex sensitization. Type II (synthetic rubber): made from synthetic rubber compounds (typically EPDM — ethylene propylene diene monomer). Synthetic rubber has better resistance to ozone, UV, heat aging, and petroleum products compared to natural rubber. Type II gloves are appropriate for environments where petroleum product contact is possible. They typically have a longer service life in outdoor environments due to better ozone resistance. For buyers with latex allergies or for applications with petroleum exposure: require Type II. For standard indoor electrical work: either type is acceptable. Encode glove.rubber_type as 'natural' (Type I) or 'synthetic' (Type II, typically EPDM). Encode glove.latex_free as 'true' for Type II synthetic rubber gloves to enable filtering for latex-allergic workers. Some manufacturers also produce thin inner gloves (cotton or nylon liners) designed to be worn under rubber insulating gloves for comfort and perspiration absorption — these liners are not electrically insulating and do not affect the class rating. Encode glove.liner_included as 'yes' or 'no' if the product includes a liner.

How do rubber insulating gloves relate to NFPA 70E arc flash requirements?

NFPA 70E (Standard for Electrical Safety in the Workplace) and OSHA 1910.269 (for electric power transmission and distribution work) both require rubber insulating gloves for energized electrical work, but they address two distinct hazards that can occur simultaneously: Shock hazard (ASTM D120 / OSHA 1910.137): rubber insulating gloves protect against electric shock — current flowing through the worker's body from contact with energized conductors. The class rating directly addresses this hazard. Arc flash hazard (NFPA 70E Table 130.7(C)(15)(a) and Table 130.7(C)(15)(b)): arc flash generates intense heat, UV light, and pressure. Rubber insulating gloves are NOT arc flash rated — the rubber compound does not meet ATPV (Arc Thermal Performance Value) requirements. For work in arc flash hazard areas, workers must wear arc-rated PPE for the flash protection boundary, INCLUDING arc-rated hand protection (arc-rated leather gloves or arc-rated composite gloves) worn OVER the rubber insulating gloves. The leather protectors that are already required over rubber insulating gloves for mechanical protection provide some arc flash thermal protection — leather arc flash gloves are specifically designed for this dual use. The combination: rubber insulating gloves (electrical insulation) + arc-rated leather protectors (mechanical protection + arc flash thermal protection) satisfies both requirements simultaneously. A worker wearing rubber insulating gloves without arc-rated leather protectors in an arc flash hazard zone is protected against shock but not against arc flash burns to the hands. Encode glove.arc_rated_leather_protector_required as 'yes' for work in NFPA 70E arc flash hazard zones — separate from the standard leather protector requirement, this indicates that the leather protector must specifically meet arc rating requirements (ATPV or EBT value specified in the site's arc flash risk assessment PPE table).

Optimization Guide

Shopify Dielectric Gloves ASTM D120 Class Voltage Schema — Class Number Does Not Equal kV Rating (Class 2 Max Use Voltage = 17000V AC, Not 2000V), Six Classes 00 Through 4, Required Color Codes, Leather Protectors Required, 6-Month Retest Mandatory Under OSHA 1910.137

Rubber insulating glove listings fail AI agent electrical safety routing through a single critical misunderstanding: the ASTM D120 class number (00, 0, 1, 2, 3, 4) is not a voltage rating in kilovolts. Class 2 gloves have a maximum use voltage of 17,000V AC — not 2,000V. An AI agent routing "Class 2 gloves for 2kV work" and "Class 0 gloves for low-voltage work" could produce an order where a Class 0 glove (1,000V max use) is sent to a 2kV application. Beyond class, dielectric gloves require leather protectors over the rubber, mandatory 6-month retesting per OSHA 1910.137, and Type I vs Type II rubber selection for petroleum environments. Encoding glove.insulating_class, glove.max_use_voltage_ac_v, glove.color_class, and glove.test_date enables voltage-accurate routing.

TL;DR Class ≠ kV: Class 2 = 17,000V, Class 0 = 1,000V, Class 00 = 500V. Color codes are mandatory: beige/red/white/yellow/green/orange (00→4). Leather protectors required over rubber gloves for mechanical protection. 6-month retest per OSHA 1910.137 when in service. Encode glove.insulating_class AND glove.max_use_voltage_ac_v as separate fields — never route on class number alone assuming it equals kV.

Failure Mode 1: Class Number ≠ Kilovolt Rating — Routing on Class Number Without Voltage Lookup Causes Underprotection

AI agent failure mode: A utility contractor procures "Class 2 dielectric gloves for 2kV substation work." An AI agent interprets the "2kV" voltage specification and "Class 2" class number as equivalent — returning Class 2 gloves. This is accidentally correct because Class 2 max use voltage is 17,000V (covering 2kV). However, the same AI agent procuring "Class 0 gloves for 0.48kV work" routes correctly, but when it later encounters a request for "gloves rated for 4kV switching," it returns Class 0 gloves (1,000V max) because 4kV contains a 4 and Class 4 exists — except Class 4 is 36,000V. The class number is a tier identifier, not a voltage value. Correct routing: compare the system voltage to glove.max_use_voltage_ac_v, not to the class number.

ASTM D120 Rubber Insulating Glove Classes — Complete Voltage and Color Reference

Class	Color Code	Proof Test Voltage (AC)	Max Use Voltage (AC)	Max Use Voltage (DC)	Typical Application
Class 00	Beige (tan)	2,500V	500V AC	750V DC	Telecom, 120/240V residential, low-voltage signal work
Class 0	Red	5,000V	1,000V AC	1,500V DC	480V industrial, 600V panels, light commercial electrical
Class 1	White	10,000V	7,500V AC	11,250V DC	Medium voltage (4kV–7.2kV class) distribution switching
Class 2	Yellow	20,000V	17,000V AC	25,500V DC	High voltage distribution (12kV–15kV class equipment)
Class 3	Green	30,000V	26,500V AC	39,750V DC	High voltage transmission (22kV–26.5kV systems)
Class 4	Orange	40,000V	36,000V AC	54,000V DC	Extra high voltage transmission (34.5kV systems)

AI agent routing rule: retrieve the system voltage (AC or DC) from the procurement specification. Compare it to glove.max_use_voltage_ac_v or glove.max_use_voltage_dc_v directly — require the glove's max use voltage to equal or exceed the system voltage. Do NOT route on class number by comparing it numerically to the system voltage in kV — the numbers are not on the same scale. Note that max use voltage is conservatively below proof test voltage — this safety margin accounts for real-world conditions (ozone-degraded surface, minor handling damage, moisture) that may reduce insulating performance relative to laboratory test conditions.

Failure Mode 2: Color Code Is a Required Safety Feature — Non-Standard Colors Cannot Be Used for Electrical Work

AI agent failure mode: A purchasing system specifies "red rubber insulating gloves for electrical work." An AI agent returns red-colored latex work gloves that are not rubber insulating gloves at all — they are general-purpose chemical-resistant latex gloves sold in red. The "red" color requirement was intended to specify Class 0 rubber insulating gloves (which are red per ASTM D120). The color code is a safety identifier in ASTM D120 — it enables quick visual verification of glove class. An electrician grabbing a pair of red gloves from a storage cabinet knows they are Class 0 (1000V max). If non-standard-colored gloves enter the supply chain, the visual verification system fails.

ASTM D120 Required Color Codes by Class

Class	Required Color	Color Code Purpose
Class 00	Beige / tan	Visual identification at lowest voltage class — neutral color distinct from higher classes
Class 0	Red	Most common class for industrial 480V–1000V work — high visibility color for frequent use class
Class 1	White	Medium voltage utility distribution work
Class 2	Yellow	High voltage distribution — matches standard high-visibility color in utility settings
Class 3	Green	Very high voltage transmission work
Class 4	Orange	Highest voltage class — orange for extra-high voltage systems

Encode glove.color_class as the standardized color name (beige, red, white, yellow, green, orange). Verify that the color in the listing matches the class: a "Class 2 green rubber insulating glove" is incorrectly described (Class 2 = yellow; green = Class 3) — this mislabeling would route a Class 3 glove to a Class 2 application (over-specification) or a Class 2 glove mislabeled green to a Class 3 application (under-specification if the color code drives selection). The color verification provides a secondary data integrity check: if glove.insulating_class and glove.color_class do not match the ASTM D120 table, flag the listing as potentially mislabeled.

Failure Mode 3: Leather Protectors Are Required Separately — Rubber Gloves Without Leather Protectors Are Mechanically Exposed

AI agent failure mode: A maintenance team orders "Class 2 rubber insulating gloves" for high-voltage switching. An AI agent returns the rubber gloves without flagging the mandatory leather protector requirement. Workers use the rubber gloves bare (no leather over them) during switching operations. A sharp conductor edge cuts through the rubber glove material at the left index finger. The cut compromises the Class 2 insulation at that point — the worker contacts the energized conductor and is injured. The rubber gloves met every specification; the missing leather protectors were the gap in the system.

Rubber Insulating Glove + Leather Protector System Requirements

Component	Function	Required Standard	Must Match Glove Class?
Rubber insulating gloves (ASTM D120)	Electrical insulation — prevents shock current from flowing through hands	ASTM D120 / OSHA 1910.137	N/A — primary protection
Leather protectors (ASTM F696)	Mechanical protection — prevents cuts, punctures, abrasion to rubber gloves during work	ASTM F696 / OSHA 1910.137(c)(2)(ix)	Yes — leather protector class must equal or exceed rubber glove class

Leather protectors are sold separately from rubber insulating gloves and must match the rubber glove class. A Class 2 leather protector (yellow, per ASTM F696 color coding which matches ASTM D120) fits over Class 2 rubber insulating gloves and provides mechanical protection for Class 2 voltage work. Using a Class 0 leather protector (red) over Class 2 rubber insulating gloves is technically possible (the leather protector is mechanical protection only), but creates visual inspection confusion — the leather protector's red color signals Class 0 while the rubber glove underneath is Class 2 yellow. Match class for class. Encode glove.requires_leather_protector as "yes" for all rubber insulating gloves. Encode glove.compatible_leather_protector_class as the class number to specify which leather protector class is appropriate.

Recommended Metafield Namespace: `glove.*` (rubber insulating / dielectric extension)

{
  "glove.insulating_class":           "2",          // "00" | "0" | "1" | "2" | "3" | "4"
  "glove.proof_test_voltage_v":       "20000",      // numeric V — 2500 | 5000 | 10000 | 20000 | 30000 | 40000
  "glove.max_use_voltage_ac_v":       "17000",      // numeric V — 500 | 1000 | 7500 | 17000 | 26500 | 36000
  "glove.max_use_voltage_dc_v":       "25500",      // numeric V — 750 | 1500 | 11250 | 25500 | 39750 | 54000
  "glove.color_class":                "yellow",     // "beige" | "red" | "white" | "yellow" | "green" | "orange"
  "glove.rubber_type":                "natural",    // "natural" (Type I) | "synthetic" (Type II, typically EPDM)
  "glove.latex_free":                 "false",      // "true" (synthetic, no latex) | "false" (natural rubber contains latex)
  "glove.requires_leather_protector": "yes",        // always "yes" — exceptions are employer-authorized per OSHA 1910.137
  "glove.retest_interval_months":     "6",          // "6" per OSHA 1910.137(b)(2)(ii)
  "glove.test_date":                  "2026-01-15", // ISO date of last factory test or in-service retest
  "glove.retest_due_date":            "2026-07-15", // test_date + 6 months — flag when purchase date > retest_due_date
  "glove.astm_standard":              "D120",
  "glove.length_inches":              "12"          // 11 | 12 | 14 | 16 — longer gloves protect the wrist and forearm
}

Voltage routing: require glove.max_use_voltage_ac_v ≥ system voltage — never route on class number as a voltage proxy. Retest compliance: flag products where glove.retest_due_date is before the expected first use date — the buyer needs a retested pair or a new pair. Petroleum environments: require glove.rubber_type = "synthetic". Latex allergy: require glove.latex_free = "true". Always pair with leather protectors: encode leather protectors as a companion SKU requirement linked via glove.requires_leather_protector = "yes".

FAQ

How do you pre-use inspect rubber insulating gloves before each work shift?

OSHA 1910.137(b)(2)(i) requires that rubber insulating equipment be inspected for damage before each day's use and immediately following any incident that may have caused damage. The standard pre-use inspection for rubber insulating gloves is the air inflation test (also called the balloon test or roll test): the worker holds the cuff of the glove closed and uses the other hand to roll and squeeze air toward the fingers until the glove is inflated like a balloon. The inflated glove is then inspected visually and by feel for: pinholes (escaping air visible as movement or audible as a hiss), cracks or cuts in the rubber, ozone checking (a pattern of small surface cracks perpendicular to the stress axis, typically on the back of the hand area — caused by ozone attacking the rubber), sticky or tacky areas (indicating chemical degradation), embedded foreign material, and swollen or soft spots (indicating swelling from chemical contact). The rolled-cuff inflation method captures air without equipment. Some workers use a specialized glove inflator device that pressurizes the glove to a set level, but the manual method is the OSHA-compliant minimum. A glove that fails air inflation (leaks air) must be removed from service immediately — a rubber glove that leaks air will also allow leakage current at voltage. Encode glove.pre_use_inspection_method as 'air-inflation' to indicate to buyers that this inspection is required before each use; some buyers are unaware that rubber insulating gloves require daily pre-use inspection beyond the 6-month electrical retest.

Can rubber insulating gloves be stored with leather protectors, and what are the storage requirements?

Rubber insulating gloves should be stored inside their leather protectors when not in use — but this requires careful attention to avoid the leather protector trapping moisture against the rubber glove. Ideal storage: store rubber gloves right-side-out (not inverted), in a cool, dark location away from sources of ozone (electric motors, UV lights, arc welding equipment), away from petroleum products, and away from heat sources. Ozone is generated by electric motors and fluorescent lighting ballasts and is one of the primary causes of rubber glove surface degradation. Many manufacturers supply rubber insulating gloves in individual canvas bags or rubber glove bags specifically designed to protect the gloves from light and ozone during storage. The leather protectors should be stored dry — moisture trapped between a leather protector and the rubber glove can promote surface degradation of the rubber. If gloves are stored inside leather protectors, ensure both are completely dry before storage. A glove that has been sitting in storage for 6 months should be inspected (air inflation test) before use even if the electrical retest date has not elapsed — storage conditions can cause deterioration. If any doubt exists after visual inspection, submit for electrical retest before use. Some utilities establish a maximum storage time (e.g., 12 months) after which gloves are retested regardless of service history, recognizing that prolonged storage in imperfect conditions may degrade the rubber. Encode glove.storage_bag_included as 'yes' for products that include a proper canvas or rubber storage bag — this is relevant to buyers who are setting up a new glove program and may not have bags.

What is the difference between rubber insulating gloves and arc flash gloves?

Rubber insulating gloves (ASTM D120) and arc flash gloves are two different PPE products protecting against two different electrical hazards that often occur in the same work scenario. Rubber insulating gloves: protect against electric shock — the flow of current through the worker's body from contact with energized conductors. The class rating specifies the maximum voltage the gloves protect against. The material is natural or synthetic rubber (dielectric material — does not conduct electricity). Arc flash gloves: protect against the heat, UV, and pressure generated by an arc flash event. Arc flash releases enormous energy rapidly (thousands of amperes flowing through air, generating temperatures to 35,000°F). Arc-rated PPE is tested under ASTM F2675 (test method for gloves) and rated by ATPV (Arc Thermal Performance Value) in cal/cm². Arc flash gloves are typically arc-rated leather or arc-rated composite materials. Why both are needed: live electrical work in panel boards, switchgear, and distribution equipment presents both a shock hazard (from direct contact with energized parts) AND an arc flash hazard (from the energy released if an arc is inadvertently initiated — e.g., tool contact between phases). The standard solution used in most utility and industrial environments: wear rubber insulating gloves (shock protection) with arc-rated leather protectors over them (mechanical protection + arc flash protection). Standard leather protectors may or may not be arc-rated — arc-rated leather protectors are specifically tested per ASTM F696 with arc flash rating. Encode glove.arc_flash_atpv_cal_cm2 for the arc flash thermal protection value of the leather protector component, or mark as 'not-arc-rated' for leather protectors that provide mechanical protection only without arc flash certification.

Do rubber insulating gloves have a shelf life before they are even put into service?

Yes. Rubber insulating gloves have a finite shelf life from the date of manufacture, independent of use history. ASTM D120 requires that the manufacturer mark each glove with the test date (date of factory electrical test). OSHA 1910.137 requires retesting every 6 months from the date the gloves are returned to service, but industry practice (and many employer safety programs) establishes a maximum shelf life from manufacture regardless of service history — typically 12 months from factory test or 6 months from initial issue, whichever comes first. Why shelf life matters: natural rubber (Type I) degrades even in storage due to ozone exposure, UV light, and thermal aging. A glove manufactured 18 months ago that has never been used in service may still have degraded electrical insulating properties due to storage-induced rubber aging. Some manufacturers stamp a 'not for use after' date on the glove cuff in addition to the test date. Buyers purchasing rubber insulating gloves for stockpiling should: (1) check the factory test date on the individual glove cuff, (2) calculate the expected first use date vs the test date + shelf life, (3) plan to retest gloves before first use if they will be stored for more than 6–12 months. Encode glove.factory_test_date (date of factory ASTM D120 electrical test as marked on the glove cuff) and glove.do_not_use_after (date from manufacturer marking if present) to enable AI agents to flag gloves at or near end of shelf life before completing a procurement order.

Are Your Dielectric Glove Listings Missing Class Voltage and Retest Fields?

CatalogScan scans your Shopify store for missing glove.insulating_class, glove.max_use_voltage_ac_v, and glove.test_date fields that cause AI agents to route rubber insulating gloves by class number as if it were a voltage rating.

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