A Professional’s Guide to High Voltage Insulating Gloves and Sleeves

For any master electrician or journeyman electrician, high voltage insulating gloves are the most critical piece of personal protective equipment (PPE) when working on or near energized circuits. Governed by OSHA and industry standards such as ASTM and NFPA 70E, these gloves provide life-saving electrical insulation — but only when selected, inspected, and maintained correctly. Understanding the different glove classes, voltage ratings, and the regulatory requirements of OSHA 1910.137 and NFPA 70E is essential for electrical professionals. Proper selection is based on the system voltage encountered, while a pre-use visual inspection is required by OSHA and an inflation (air) test is a widely recommended industry practice. The complete system — rubber insulating gloves, leather protectors, and, when needed, rubber insulating sleeves — must be visually checked before each use and subjected to periodic dielectric testing to ensure integrity. While this system provides effective shock protection, adequate arc flash protection requires additional, specifically rated PPE as determined by NFPA 70E. This guide provides the essential knowledge for maintaining compliance and, most importantly, ensuring your safety on the job.

Understanding Glove Classes and Voltage Ratings

The foundation of electrical glove safety lies in a classification system defined by ASTM in ASTM D120. This specification establishes six distinct classes of insulating gloves, each corresponding to a maximum use voltage (AC). Choosing a glove with a maximum-use voltage that meets or exceeds the system you will encounter is a fundamental safety requirement. A journeyman electrician working on an industrial electrical transformer will require a higher class of glove than one working on residential service panels.

The classes are indicated on the gloves and stamped with the class and test dates (manufacturers may also include additional markings):

• Class 00: Maximum use voltage 500 V AC (ASTM D120)
• Class 0: Maximum use voltage 1,000 V AC (ASTM D120)
• Class 1: Maximum use voltage 7,500 V AC (ASTM D120)
• Class 2: Maximum use voltage 17,000 V AC (ASTM D120)
• Class 3: Maximum use voltage 26,500 V AC (ASTM D120)
• Class 4: Maximum use voltage 36,000 V AC (ASTM D120)

Note: ASTM D120 defines the classes by AC maximum-use voltages. Some practitioners refer to DC “equivalents” in the field, but DC equivalencies are not defined by ASTM and can vary with the calculation method and manufacturer guidance — always follow the glove manufacturer’s instructions and your employer’s written safety program. Also note that glove markings typically show the class and test/timestamp; there is no single mandatory color-coding system set by ASTM.

Using a Class 2 glove, for example, is appropriate for tasks up to its 17,000 V AC rating, but would be insufficient and dangerous on a 33 kV system, where a higher-class glove is required. Always verify the system’s voltage before selecting your PPE.

The Regulatory Framework: OSHA and NFPA 70E

Two primary authorities govern the selection, inspection, and testing of high-voltage PPE in the United States: OSHA and NFPA 70E.

OSHA 1910.137, “Electrical Protective Equipment,” requires that insulating gloves and other electrical protective equipment be appropriate for the voltage involved and that gloves be inspected before each use. OSHA also requires electrical (dielectric) testing at the intervals specified in the standard and in the employer’s written program. OSHA references consensus standards such as ASTM for test and inspection methods.

NFPA 70E, the “Standard for Electrical Safety in the Workplace,” provides the practical guidance for implementing safe work practices, performing hazard assessment, and selecting the correct PPE for shock and arc flash protection. NFPA 70E is the primary consensus guide for determining when rubber insulating gloves and leather protectors are required and for defining safe work procedures. For more information, you can explore how NFPA 70E updates have changed job safety planning and the revised methods for voltage verification for electrical safety.

The Complete Insulating Glove System

Effective protection requires more than just the rubber glove itself. A complete system consists of three key components, each playing a vital role.

Rubber Insulating Gloves

This is the core component providing the primary electrical insulation. The gloves are manufactured to meet the dielectric strength requirements of ASTM D120 and are made from natural or synthetic rubber compounds. They are categorized by class per ASTM D120 and are marked with test dates and class information.

Leather Protectors

Leather protectors are intended to protect the insulating glove from mechanical damage such as cuts, abrasions, and punctures. NFPA 70E details the use of protectors with insulating gloves for shock protection based on the hazard assessment. OSHA references standards and employer programs that require appropriate protective equipment for the hazard.

Rubber Insulating Sleeves

Where an electrician’s arms might be exposed to live parts, rubber insulating sleeves protect the area from the glove cuff up toward the shoulder, ensuring continuous insulation when required by the job. Sleeves must be sized, inspected, and tested according to ASTM and employer procedures.

Daily Glove Inspection: Your First Line of Defense

OSHA 1910.137 requires that insulating gloves be inspected before each use. Most electricians incorporate these steps into a pre-use routine:

1. Visual Inspection: Carefully inspect the entire surface of the glove, inside and out. Look for cuts, holes, tears, embedded objects, cracks (including ozone cutting), or changes in texture such as swelling, hardening, or stickiness.
2. Air Test (Inflation): Industry practice and ASTM guidance recommend rolling the cuff to trap air and inflating the glove. Gently squeeze and listen for escaping air or feel for loss of pressure — an effective quick check for pinholes.
3. Repeat for the Interior: Turn the glove inside out and repeat the visual and air tests to catch defects not visible from the exterior.
4. Inspect the Leather Protectors: Check for embedded metal, excessive wear, or damage that could compromise the rubber glove beneath.
5. Check the Test Date: Verify the glove’s test date stamped on the cuff and follow employer procedures for out-of-date equipment.

Periodic Retesting and Dielectric Testing

In addition to the pre-use inspection, insulating gloves must be electrically tested (proof-tested) according to employer procedures and applicable consensus standards. Industry practice and OSHA/ASTM guidance commonly use a six-month proof-test interval for gloves in regular service; gloves that are stored and not placed in service typically require revalidation before initial use. Testing is performed by qualified testers using calibrated equipment to detect leakage and ensure dielectric integrity.

Key takeaways for retesting include:

• Have gloves electrically tested before first issue and at intervals required by the employer program and consensus standards (commonly six months for gloves in service).
• If gloves were tested but not issued for service, follow your employer’s program on revalidation before first use (many programs use a 12-month administrative limit for unused-tested items).
• Never use a glove past its test date or one that fails a pre-use inspection; remove it from service immediately.
• Repairs to the insulating area are generally not permitted; follow manufacturer guidance and employer procedures for disposition.

Your hands are your livelihood. Protect them with proper glove procedures.

The Role of the NEC in Worker Safety

While standards like NFPA 70E and OSHA 1910.137 directly govern PPE and safe work practices, the National Electrical Code (NEC) helps create safer electrical systems via proper installation, grounding, and overcurrent protection requirements. Understanding how the NEC improves electrical worker safety provides a more holistic view of risk mitigation — combining safe installations with safe work practices.

Primary Sources

• OSHA Standard 1910.137 – Electrical Protective Equipment (see OSHA.gov)
• NFPA 70E – Standard for Electrical Safety in the Workplace® (see NFPA.org)
• ASTM D120 – Standard Specification for Rubber Insulating Gloves (see ASTM.org)

Frequently Asked Questions

How often do high voltage insulating gloves need to be tested?

OSHA 1910.137 and ASTM guidance require electrical testing before first issue and at regular intervals while in service. The common industry interval for gloves in regular use is every six months; consult your employer’s written program and manufacturer guidance for exact intervals and recordkeeping requirements.

Can I use Class 2 gloves for any high voltage voltage?

No. Class 2 gloves are rated for a maximum use voltage of 17,000 V AC (ASTM D120). Using them on a system with a higher voltage, such as a 33 kV line, is unsafe. Always match the glove class to the specific voltage and the hazard analysis for the task.

What is the difference between lineman gloves and electrician gloves?

Terminology varies by industry. “Lineman gloves” often refers to the higher-class gloves used by utility lineworkers on overhead distribution and transmission systems. Any worker, regardless of title, must use insulating gloves of the appropriate class for the voltages and tasks they perform.

What does NFPA 70E say about insulating gloves?

NFPA 70E requires the use of suitable shock PPE based on the risk assessment. When the hazard analysis identifies a shock risk, NFPA 70E specifies appropriate insulating gloves and the use of leather protectors, along with training, inspection, and testing per consensus standards like ASTM D120 and OSHA guidance.