How to Store and Use Electrical Insulating Mats: Best Practices Guide

Electrical insulating mats are essential safety equipment. A mat that was fully compliant when purchased can silently lose its dielectric integrity through incorrect storage, improper use or missed inspection cycles.

This guide covers the complete post-purchase lifecycle of electrical insulating mats: correct storage conditions, safe usage guidelines, periodic inspection criteria, retesting requirements, and retirement rules - all aligned with IEC 61111, IS 15652, and ASTM D178 standards.

Why Storage and Usage Practices Directly Affect Mat Safety

Rubber insulating mats degrade in three primary ways and all three are preventable:

1. Ozone degradation: Ozone attacks the molecular chains in rubber compounds, causing surface crazing and micro-cracking. Ozone is generated by UV light, high-voltage electrical equipment, and electric motors. A mat stored near any of these sources will degrade faster than one stored in a clean, enclosed area regardless of voltage class or brand.

2. Chemical contamination: Oils, solvents, petroleum products, and certain cleaning agents penetrate rubber and reduce dielectric strength. A mat contaminated with transformer oil may look physically intact but fail a dielectric test.

3. Physical damage: Folds, kinks, compression under heavy loads, and sharp-edged debris create mechanical stress points that become electrical failure paths under high-voltage conditions.

None of these appear on a purchase certificate. They develop in the field, which is why storage and usage discipline is as important as product specification.

Correct Storage of Electrical Insulating Mats

Storage Environment

• Store mats in a clean, dry, enclosed space, away from ozone-generating sources  like motors, transformers, UV lighting, welding equipment.
• Ideal storage temperature: +10°C to +30°C. Avoid cold stores or areas with extreme heat fluctuation.
• Keep away from direct sunlight: UV accelerates ozone-induced surface degradation.
• No contact with oils, solvents, acid, petroleum products or aggressive cleaning agents at any stage of storage.
• Store in a location with low humidity, condensation on rolled mats promotes surface tracking contamination over time

Rolling vs. Folding

Always roll, never fold.

Folding an insulating mat creates a permanent crease line. Under that crease, the rubber compound is under continuous mechanical stress. Over time this creates a micro-crack that propagates through the mat’s cross-section. A folded mat with a crease line at the crease will fail dielectric testing and must be retired.

• Roll mats loosely around a cardboard or foam core.
• Store rolls horizontally on racks, not standing vertically.
• If storing for extended periods, wrap in black polyethylene film to block UV and ozone.

Storage Duration and Validity

Purchasing a certified mat does not give it indefinite shelf life. No electrical insulating mat should be used unless it has been electrically tested within the previous 12 months. The test certificate issued at point of manufacture does not extend through storage time.

If you receive a shipment of mats and store them for 8 months before deployment, test them before first use.

Correct Usage of Electrical Insulating Mats

Placement

• Position the mat so the operator stands fully on the mat while working near or operating live equipment.
• Ensure complete coverage of all operating positions in front of switchgear panels, MCCs, and control boards.
• In switchrooms and substation control areas: mat coverage should extend across the full width of the panel plus a minimum of 1 metre in front of the equipment operating zone
• Never use mats on uneven or sharply profiled floors without first levelling the surface, a mat that rocks or buckles under foot creates both a trip hazard and a potential mechanical stress point

Voltage Class Must Match the Installation

This cannot be overstated. Using a Class 0 (1,000V rated) mat in a 6.6kV or 11kV switchroom is a safety violation, not a conservative precaution.

Select the class where the maximum use voltage exceeds the highest system voltage present at the work location, not just the nominal voltage.

Handling During Use

• Never drag mats across abrasive concrete or metal edges.
• Remove footwear with metallic toe caps or exposed metal studs before stepping onto Class 2-4 mats in live-line work environments.
• Never use mats as a surface for tools, equipment or materials as contact with sharp edges creates puncture damage that is not always visible on the surface
• Never use a mat that has a visible oil sheen, stain or chemical residue without first cleaning and drying it thoroughly.

Inspection: What to Check and How Often

Inspection Frequency

No electrical insulating mat should be used unless it has been inspected and/or electrically tested within the previous 12 months.

In practice, most EHS programmes specify:

• Before each shift / daily: Quick visual check in high-frequency use areas (control rooms, substations with regular maintenance activity).
• Monthly: Documented visual inspection with records.
• Annually: Full electrical retest per IEC 61111 by an accredited laboratory.

Visual Inspection Checklist

Check for the following during every documented inspection:

Surface damage:

• Cuts, punctures, or embedded objects (metal swarf, sharp debris).
• Surface crazing or network cracking (ozone damage signature).
• Permanent fold lines, kinks, or deformation.
• Scorch marks or tracking paths from previous electrical events.

Contamination:

• Oil, grease, or chemical staining.
• Conductive dust or carbon deposits.
• Any visible liquid saturation.

Structural integrity:

• Thinning at areas of frequent foot traffic.
• Edge delamination or separation.
• Missing or illegible class marking / standard compliance markings.

Electrical Retesting

Annual electrical retesting must be conducted by a laboratory equipped to perform dielectric proof tests per IEC 61111 protocols. The test applies a proof voltage to verify the mat’s dielectric integrity at its rated class.

Retesting certificates should be filed against the mat’s serial/batch number and kept accessible at the site for regulatory inspections by HSE, EHS audit teams, and insurance surveyors will request this documentation.

If a mat is sent for retesting and fails, the laboratory should confirm destruction before issuing a non-compliance report. Do not accept a mat returned with a fail report without destruction confirmation.

Cleaning Electrical Insulating Mats

Clean mats extend service life and maintain reliable surface insulation. Incorrect cleaning destroys them.

Approved cleaning method:

• Wipe with a clean, dry or slightly damp cloth.
• Use mild soap solution (pH neutral) and rinse thoroughly with clean water and allow it to fully air-dry before returning to service.
• Dry flat or rolled, never in direct sunlight or near heat sources.

Never use:

• Petroleum-based solvents (acetone, petrol, turpentine, mineral spirits).
• Acid or alkaline industrial cleaners.
• Steam cleaning or pressure washing.
• Abrasive pads or wire brushes.
• Any solvent that leaves a residue.

After any chemical cleaning, allow 24 hours of air drying before electrical retesting or return to service.

Retirement and Replacement

An insulating mat reaches end-of-life when:

• It fails visual inspection (any item on the checklist above).
• It fails annual electrical retesting.
• It has experienced a confirmed electrical event ( like flashover, shock incident, tracked arc), removed immediately regardless of appearance.
• Its class markings are no longer legible, unidentifiable class.
• It has exceeded the manufacturer’s recommended service life.

Retirement procedure: Cut the mat into sections to prevent reuse. Do not donate or resell retired mats. Do not repurpose them as non-electrical floor coverings in the same facility, this creates a risk that a retired mat re-enters the electrical safety programme by mistake.

Conclusion

For IEC 61111, IS 15652, and ASTM D178 certified insulating mats with full documentation, contact our team or explore the product range.