Maintenance of electrical equipment

Employers must keep wiring components and utilization equipment in hazardous locations in a dust-tight, dust-ignition-proof, or explosion-proof condition as appropriate, and must eliminate loose or missing screws, gaskets, threaded connections, seals, or other impairments to a tight condition (Requirement in 1926.431).

• Maintain enclosures, covers, seals, and conduit fittings so they prevent dust or vapor ingress and eliminate ignition sources when the location demands it.
• Repair or replace defective parts immediately; do not leave covers, gaskets, or seals missing in hazardous locations.
• Follow the equipment manufacturer’s instructions and any applicable certified design requirements (NRTL listings) when restoring protective features.

Cites: Requirement in 1926.431.

It means maintaining the equipment so that dust, combustible dust clouds, flammable vapors, or ignitable atmospheres cannot get into electrical parts and create an ignition source; maintenance must restore whatever level of protection the installation requires (Requirement in 1926.431).

• Dust-tight: prevent fine dust ingress that could create combustible layers or conductive buildup.
• Dust-ignition-proof: prevent dust from entering enclosures and prevent internal arcs or sparks from igniting dust outside the enclosure.
• Explosion-proof: ensure enclosures contain any explosion and prevent transmission of the explosion to the surrounding atmosphere.

Use manufacturer guidance, NRTL listings, and recognized industry practice to determine which protection applies and how to restore it. Cites: Requirement in 1926.431.

No — temporary fixes that do not restore the equipment to its required dust-tight, dust-ignition-proof, or explosion-proof condition are not acceptable in hazardous locations (Requirement in 1926.431).

• Repairs must restore the original protective function; quick patches that leave gaps, loose fasteners, or missing gaskets create hazards and violate the maintenance requirement.
• If a short-term measure is absolutely necessary to continue operations, limit use, isolate the area, and complete a permanent repair as soon as practicable.

Cites: Requirement in 1926.431.

The employer is responsible for ensuring that all wiring components and utilization equipment in hazardous locations are maintained in the required condition and that there are no loose or missing screws, gaskets, threaded connections, seals, or other impairments (Requirement in 1926.431).

• Employers must set up inspection and maintenance programs, assign qualified personnel, and ensure repairs restore required protection.
• Supervisors and competent persons should verify work is done correctly; employees should report damaged enclosures or missing seals immediately.

Cites: Requirement in 1926.431.

Section 1926.431 does not specify a fixed inspection interval; employers must ensure equipment is maintained in the required condition and should establish inspection frequency based on hazard, manufacturer recommendations, and operating conditions (Requirement in 1926.431).

• Use a risk-based approach: inspect more often where dust accumulation, corrosive environments, vibration, or mechanical damage are likely.
• Documented hazard assessments and written certification for PPE and related controls are good practice; see OSHA guidance on performing hazard assessments to select controls and PPE (PPE hazard assessment LOI).

Cites: Requirement in 1926.431 and PPE hazard assessment LOI.

You must promptly restore the protective condition — stop the hazard, secure the area if necessary, and repair or replace the damaged gasket, seal, or fastener so the equipment returns to its dust-tight, dust-ignition-proof, or explosion-proof condition (Requirement in 1926.431).

• If repair cannot be completed immediately, isolate or de-energize the equipment and restrict access until permanent repair is done.
• Use replacement parts and methods that restore the original protection (manufacturer or NRTL-approved components).

Cites: Requirement in 1926.431.

Only qualified and trained personnel should perform maintenance that affects protection in hazardous locations; the employer must ensure workers are competent to maintain dust-tight or explosion-proof features (Requirement in 1926.431).

• "Qualified" means trained and knowledgeable about the hazards, the protective requirements of the equipment, and the correct repair procedures.
• Employers should perform a hazard assessment and provide training or supervision so maintenance restores required protection; see OSHA guidance on hazard assessments for PPE and related protections (PPE hazard assessment LOI).

Cites: Requirement in 1926.431 and PPE hazard assessment LOI.

You must repair or replace the damaged component so the fixture again provides the required explosion-proof or dust-ignition protection; replacement parts should restore the certified protection and meet the manufacturer's or NRTL-listed design (Requirement in 1926.431).

• Use parts that match the enclosure’s safety rating or are approved by the equipment manufacturer or a Nationally Recognized Testing Laboratory (NRTL).
• Avoid field-modified parts that could degrade protection; document repairs and keep records of approved replacements.

Cites: Requirement in 1926.431.

Verification should restore and confirm the equipment’s required protective condition by visual inspection and appropriate fastening or testing methods recommended by the manufacturer or applicable standards (Requirement in 1926.431).

• Visual inspection for missing or loose screws, damaged threads, or degraded gaskets.
• Use specified torque values, gasket replacement, sealing compounds approved by the manufacturer, and pressure or ingress tests where applicable.
• Keep inspection checklists and records showing repairs restored tightness.

Cites: Requirement in 1926.431.

Covers and gaskets may be removed only as necessary for testing or repair, but they must not be left off in hazardous locations where their absence impairs the required protective condition; replace them as soon as the work requires and take interim protective measures (Requirement in 1926.431).

• If removal exposes a hazard, de-energize and isolate the equipment and restrict access until covers and seals are replaced.
• Use temporary barriers or permit systems only when they ensure worker safety and do not leave the area exposed to dust or vapors.

Cites: Requirement in 1926.431.

Yes — utilization equipment, which includes tools and cords used in hazardous locations, must be maintained in the appropriate condition for that location so they do not become an ignition source or allow hazardous material ingress (Requirement in 1926.431).

• Use tools and cords rated and listed for the hazardous location or otherwise maintained so they do not introduce sparks, heat, or exposed conductors into the environment.
• Inspect flexible cords, plugs, and equipment housings for damage; repair or replace damaged gear with approved replacements.

Cites: Requirement in 1926.431.

While 1926.431 does not explicitly require written maintenance records, employers should document inspections, repairs, and hazard assessments to demonstrate they maintained equipment in the required condition and to track recurring problems (Requirement in 1926.431).

• Documentation helps show compliance and supports preventive maintenance schedules.
• For related programs (like PPE selection), OSHA expects written certification of hazard assessments where PPE is required; see the PPE hazard assessment LOI for guidance on documenting assessments (PPE hazard assessment LOI).

Cites: Requirement in 1926.431 and PPE hazard assessment LOI.

If maintenance may disturb asbestos-containing building materials, the asbestos construction standard 29 CFR 1926.1101 and related asbestos guidance apply; employers must follow those requirements in addition to maintaining electrical equipment in a safe condition (Requirement in 1926.431).

• OSHA has stated that remediation activities involving asbestos-containing building materials are covered by the construction asbestos standard, and employers must comply with its exposure assessment, work practices, and respiratory protection requirements (Asbestos remediation protocols LOI).
• Coordinate electrical maintenance with asbestos controls (containment, monitoring, PPE) to protect workers and preserve required protective conditions on equipment.

Cites: Requirement in 1926.431 and Asbestos remediation protocols LOI.

Yes — conduit seals, cable glands, threaded connections, and fittings that are part of the enclosure system must be maintained so the overall installation remains dust-tight, dust-ignition-proof, or explosion-proof as required by the location (Requirement in 1926.431).

• Any penetration or connection that compromises the enclosure’s integrity must be repaired using compatible, rated components.
• Use manufacturer-specified sealing methods or NRTL-listed explosion-proof fittings to preserve the enclosure’s protective rating.

Cites: Requirement in 1926.431.

An enclosure or seal is impaired when screws, gaskets, threads, or seals are loose, missing, damaged, or otherwise allow ingress of dust, vapors, or ignition sources; employers should inspect for visible damage, test seals where applicable, and use manufacturer criteria to judge impairment (Requirement in 1926.431).

• Common signs of impairment: missing screws, torn or hardened gaskets, cracked housings, loose threaded entries, corrosion, or evidence of dust/vapor ingress.
• When doubt exists, follow the manufacturer’s acceptance tests or consult a qualified person to determine if the equipment still meets the required protection.

Cites: Requirement in 1926.431.