Where should electrical insulation mats be laid in inverter rooms, battery rooms and medium-voltage switchgear rooms?

When installing electrical insulation mats in inverter rooms, battery rooms and medium-voltage switchgear rooms, priority should be given to covering the areas where staff actually stand whilst carrying out electrical operations, inspections and maintenance, rather than automatically covering the entire room. In the inverter room, particular attention should be paid to the areas in front of the inverter cabinets and AC/DC power distribution equipment; in the battery room, the focus should be on the operating positions for battery maintenance, chargers and DC power distribution equipment; whilst in the medium-voltage switchyard, attention should be centred on the operating surfaces of the medium-voltage switchgear. The specific installation scope, insulation rating and material requirements must be determined based on the equipment voltage, operational risks, site layout and applicable standards.

I. Where should insulating mats be laid in an inverter room?

Inverter rooms are typically equipped with power inverters, AC power distribution cabinets, DC isolation equipment and associated control systems. During equipment operation, status checks and maintenance, staff may need to approach live electrical equipment.

Therefore, priority should be given to laying insulating mats in front of equipment where personnel need to stand to carry out electrical operations.

1. Prioritise assessment of the area in front of inverter cabinets

Inverter cabinets are one of the most critical equipment areas within an inverter room.

When determining the laying position, particular attention should be paid to:

• The routine operating positions in front of the inverter cabinets.
• The actual positions where personnel stand during equipment inspection and maintenance.
• The operational space available to staff once the cabinet doors are open.
• Locations where electrical measurements or fault-finding are required.

If multiple inverter cabinets are installed side by side and personnel need to operate continuously between adjacent units, the use of a continuous strip of insulating mats may be considered to minimise unnecessary gaps between different operational areas.

However, insulating mats should not be laid unconditionally in front of all cabinets simply because the equipment is neatly arranged. Decisions should be based on actual electrical risks and work procedures.

2. AC distribution cabinets and DC isolation equipment require separate assessment

AC and DC electrical circuits may co-exist within an inverter room.

Therefore, insulating mats must not be selected based solely on the inverter’s rated power or the room’s designation.

In particular, for DC disconnect switches, it is essential to verify the DC voltage conditions and whether the insulating mats are suitable for the relevant DC operating scenarios.

IEC 61111:2026 specifies the scope of application for electrical insulating mats, covering AC use up to 36,000 V AC, as well as applications up to 36,000 V AC and 54,000 V DC under corresponding AC/DC operating conditions. Specific product selection must still be based on product class and test evidence; the suitability of a particular product cannot be determined solely on the basis of the standard’s general scope of application.

3. Do not interfere with the normal operation of inverter equipment

The laying of insulating mats must also be coordinated with the equipment layout in the inverter room.

Klíčové body ke kontrole:

• Whether they obstruct equipment air inlets and heat dissipation pathways.
• Whether they obstruct the normal opening of cabinet doors and access panels.
• Whether they cover cable trenches, drainage facilities or necessary maintenance areas.
• Whether they affect equipment handling and maintenance access routes.
• Whether they create a risk of raised edges or tripping hazards in pedestrian walkways.

Insulating mats should serve electrical operating positions and must not compromise equipment operation or pedestrian access in order to increase coverage area.

II. Where should insulating mats be laid in battery rooms?

The selection of insulating mats for battery rooms requires greater caution than in standard switchgear areas.

Different battery technologies present distinct electrical and environmental risks. Lead-acid batteries may involve electrolyte leakage and gases generated during charging; nickel-cadmium batteries involve alkaline electrolytes; whilst lithium-ion batteries require assessment in conjunction with the electrical and thermal safety requirements of the energy storage system.

Therefore, standard electrical insulating mats cannot be used directly as a universal flooring material for the entire battery room.

1. Prioritise assessment of the areas in front of charging equipment and DC power distribution equipment

The following locations within the battery room require particular attention:

For example, when staff need to carry out inspections and maintenance in front of the DC distribution cabinet, the need for electrical insulation mats can be determined based on the on-site risk assessment, and products should be selected in accordance with the relevant DC voltage and standard requirements.

2. Electrical insulating mats should not be laid beneath battery racks as a matter of course

This is an issue that is easily overlooked in battery room design.

The area beneath battery racks typically requires consideration of equipment support, mounting and fixing, floor load-bearing capacity, leakage management and maintenance space.

Placing insulating mats directly beneath battery racks may affect:

• Stable contact between the battery rack and the floor.
• Equipment fixing and installation structures.
• Collection and treatment of electrolyte leaks.
• Inspection and maintenance beneath the battery racks.
• Installation conditions specified by the battery system manufacturer.

Therefore, electrical insulation mats should generally be prioritised for the standing areas where personnel actually carry out electrical operations, rather than being laid beneath battery racks by default.

3. A distinction must be made between electrical insulation and chemical protection

If lead-acid batteries are used in the battery room, particular attention must also be paid to the effects of electrolyte on the floor and materials.

US OSHA 29 CFR 1926.441 stipulates requirements for ventilation, acid-resistant flooring, electrolyte handling and emergency washdown facilities for battery and charging areas within its scope.

This means that electrical insulation mats cannot replace the acid-resistant flooring, spill containment facilities and other safety measures required in battery rooms.

When procuring, the following should be confirmed:

• Whether the insulation mat material is compatible with the chemicals it may come into contact with on site.
• Whether cleaning agents will affect the rubber material.
• Whether independent collection and treatment measures are in place in the event of an electrolyte spill.
• Whether the product will impede drainage and emergency response procedures.
• Whether the fire safety, ventilation and other safety facilities in the battery room meet project requirements.

For lithium-ion battery energy storage rooms, thermal runaway, fire and emergency response requirements should also be considered in accordance with the project design. Insulating mats can only fulfil their verified role of providing insulation protection and cannot replace the fire safety and thermal safety design of the energy storage system.

4. Do not confuse ESD mats with electrical insulation mats

Battery rooms may contain battery management systems (BMS), electronic control equipment and electrical maintenance areas simultaneously.

If electronic equipment has electrostatic control requirements, appropriate products must be selected in accordance with the ESD control plan.

ESD mats and electrical insulation mats serve different functions:

• ESD mats are used for electrostatic control and typically require compliance with specified earthing and personnel electrostatic control measures.
• Electrical insulation mats are used for the electrical protection of personnel under specified conditions.

One must not assume that these two products are interchangeable simply because they both appear as rubber mats.

III. Where should insulation mats be laid in medium-voltage substations?

Medium-voltage switchyards are one of the most typical application scenarios for electrical insulation mats.

Common equipment includes medium-voltage switchgear, circuit breaker cabinets, busbar cabinets, metering cabinets and protection and control equipment.

Compared to inverter rooms and battery rooms, the priorities for laying insulation mats in medium-voltage switchyards are more clearly defined: priority should be given to assessing the operating surfaces of medium-voltage switchgear, as well as areas where personnel need to stand to carry out inspections and maintenance.

1. The area in front of medium-voltage switchgear is a priority assessment area

When operating medium-voltage switchgear, staff typically need to stand in front of the cabinet to perform switching operations, status checks or equipment maintenance.

Therefore, particular consideration should be given to:

• The area in front of switchgear operating handles and control devices.
• Circuit breaker operating and maintenance positions.
• Work areas where personnel are required to carry out inspections and tests.
• Continuous operating areas comprising multiple adjacent switchgear units.

If multiple switchgear units are installed side by side, a continuous laying scheme may be adopted based on the actual operating range.

This reduces the gaps in the exposed floor between adjacent units and facilitates the standardisation of the dimensions and specifications of the insulating mats.

2. Is it necessary to lay insulation mats at the rear of switchgear?

It is not necessary to lay insulation mats at both the front and rear of all medium-voltage switchgear.

The decision on whether to lay mats at the rear should be based on the equipment’s structure and actual operational requirements.

If a medium-voltage switchgear cabinet adopts a ‘front-operated, rear-maintained’ layout, separate laying schemes may be drawn up for the front and rear areas based on their respective working conditions.

If there is no need for personnel to operate from the rear of the equipment, nor are there any other risk assessment requirements, there is no need to add insulating mats merely for the sake of formal symmetry.

3. Insulating mats cannot replace the substation earthing system

This point must be made clear.

The purpose of insulating mats is to provide supplementary electrical insulation protection for the surface on which personnel stand, subject to applicable conditions.

They cannot replace:

• the substation earthing grid.
• equipment protective earthing.
• Equipotential bonding.
• Electrical isolation and voltage testing procedures.
• Prescribed personal protective equipment.
• Approved electrical safety work procedures.

Particularly in areas with medium- and high-voltage equipment, issues such as elevated ground potential, contact voltage and step voltage must be addressed in conjunction with the design of the earthing system and on-site risk assessments.

It cannot be assumed that all electric shock risks have been controlled simply by laying insulating mats on the floor.

IV. How to determine the coverage area, grade and material requirements for insulating mats?

Once the laying position has been determined, three practical issues still need to be addressed: coverage area, product grade and material structure.

1. Determine the coverage area based on the actual standing positions of personnel

The dimensions of the insulating mat should not be determined solely by the external dimensions of the equipment cabinet.

For example, a switchgear cabinet with a width of 800 mm does not necessarily mean that laying an insulating mat 800 mm wide will satisfy actual operational requirements.

It is also necessary to consider the physical position of personnel whilst standing, the space required for opening cabinet doors, and the range of movement during equipment operation and maintenance.

It is recommended to determine the dimensions by following these steps:

1. Measure the actual width of the switchgear cabinet.
2. Determine the positions where staff routinely stand and carry out operations.
3. Assess whether continuous installation is required between adjacent cabinets.
4. Confirm the space required for cabinet doors, circuit breaker withdrawal and maintenance operations.
5. Check whether the edges of the insulating mats obstruct passage.
6. Determine the width, length and cutting plan of the rolls based on the site floor plan.

For multiple adjacent cabinets, priority should be given to continuous installation to minimise seams and unnecessary exposed areas.

However, the final dimensions should still be determined based on project drawings, equipment layout and actual risk assessments; a single fixed size should not be applied across all electrical rooms.

2. Select the IEC class based on actual AC/DC voltage conditions

Inverter rooms, battery rooms and medium-voltage substations may involve different voltage conditions.

Therefore, when selecting insulating mats, the following should first be confirmed:

• Whether the equipment is AC or DC.
• The operating voltage of the relevant electrical systems.
• The electrical risks at the actual operating location.
• The applicable standards and ratings specified by the project.
• Whether the product has test documentation for the corresponding rating.

IEC 61111:2026 is a key product standard for electrical insulating mats.

It applies to electrical insulating mats made from flexible insulating materials. Procurement personnel should select products based on the ratings, conditions of use and test requirements specified in the standard, rather than simply selecting a rating based on room type.

For example, it cannot be assumed that all medium-voltage switchgear rooms must use the same rating, nor can it be assumed that, simply because a battery room uses a DC system, the product’s DC applicability can be disregarded.

Ultimately, the specific equipment conditions, project specifications and product test evidence should be taken as the definitive criteria.

3. Determining Surface Texture and Materials Based on the Environment

The requirements for the surface and materials of insulating mats may also vary across these three scenarios.

The surface texture can be selected according to the specific environment:

• Hladký povrch: The surface is flat and easy to clean, suitable for environments where the accumulation of surface dirt needs to be controlled.
• Corrugated Surface: Features a directional texture; slip resistance and cleaning requirements can be assessed based on site conditions.
• Diamond Surface: A diamond-patterned texture; suitability can be assessed based on the actual floor conditions and foot traffic.

It cannot simply be assumed that a single texture is suitable for all rooms. When making a selection, factors such as whether the floor is dry or wet, the presence of dust and grease, and routine cleaning methods should also be taken into account.

4. Confirm that the product documentation matches the actual model supplied

For EPC projects, substation construction projects and industrial power distribution projects, procurement staff should verify the following prior to order confirmation:

It is particularly important to note that the test report must correspond to the actual product model and configuration being procured.

A test report for one specific product model cannot be used to directly demonstrate that products with different thicknesses, materials or structures also meet the same requirements.

Conclusion: Design an insulation mat laying plan based on the actual operational location

Although inverter rooms, battery rooms and medium-voltage substations may all require electrical insulation mats, the equipment structures and environmental conditions differ across these three scenarios; therefore, an identical laying plan cannot be adopted for all.

In inverter rooms, priority should be given to assessing the area in front of the inverter cabinets and AC/DC power distribution equipment; in battery rooms, priority should be given to charging equipment, DC distribution cabinets and actual battery maintenance locations, whilst also verifying the battery chemistry and floor corrosion protection requirements; in medium-voltage switchyards, the focus should be on the operating surfaces of medium-voltage switchgear, as well as areas where personnel need to stand to carry out maintenance.

Once the installation locations have been determined, select suitable products based on AC/DC voltage conditions, IEC 61111 ratings, product test documentation, material performance and on-site dimensions.

JINPOWER supplies electrical insulating mats and related electrical safety equipment, and can assist in confirming suitable product configurations based on the project’s equipment layout, electrical rating, operating environment and dimensional requirements.

navštivte JINPOWER Electrical Insulating Mats and provide project drawings, the required rating and installation dimensions to facilitate further confirmation of product specifications.

Bezpečnostní instrukce: Electrical insulating mats are auxiliary electrical protection equipment and cannot replace earthing systems, electrical isolation, voltage testing, personal protective equipment or approved safe working procedures. Specific installation locations and usage requirements should be determined in accordance with the project’s risk assessment, applicable regulations, relevant standards and the equipment manufacturer’s instructions.