Polyester cabinets: how to choose the right cabinet for your industrial environment

Europoly: a French manufacturer of polyester cabinets and enclosures for demanding industrial environments. Technical guide

A polyester enclosure is an electrical enclosure made from glass-fibre-reinforced polyester, designed to protect electrical equipment in corrosive, damp or UV-exposed environments. Thanks to its corrosion resistance, Class II electrical insulation and mechanical strength, it offers a durable alternative to traditional metal enclosures.

Polyester cabinets and enclosures are now used in a wide range of sectors: water treatment, photovoltaics, the chemical industry, railway infrastructure, industrial ports and electricity distribution networks. Choosing the right solution depends on several criteria: the installation environment, the IP rating, the IK impact resistance rating, thermal constraints and regulatory requirements.

Choosing a polyester cabinet is about more than just comparing one catalogue entry with another.

The right choice depends on the actual site environment, the IP and IK ratings specified in the specifications, electrical safety requirements and the overall cost over the installation’s service life.

Europoly has been designing and manufacturing glass-fibre-reinforced polyester enclosures, cabinets and housings for industrial use for over twenty years, offering both standard ranges and bespoke solutions for the most demanding environments.

What is an industrial polyester cabinet?

An industrial polyester enclosure is a technical housing designed to house and protect electrical, electronic or control equipment in demanding environments.

Made from glass-fibre-reinforced polyester, it offers mechanical and chemical properties that are particularly well suited to outdoor installations or harsh environments. Unlike a metal cabinet, its resistance to corrosion does not depend on a surface treatment or coating that may deteriorate over time. This resistance is directly linked to the very nature of the material.

Polyester enclosures can be used for a wide variety of applications: electrical distribution, industrial automation, monitoring, metering, telecommunications, railway infrastructure, photovoltaic installations and wastewater treatment plants.

Depending on requirements, they can take the form of compact polyester enclosures, high-capacity modular cabinets or technical enclosures incorporating specific equipment.

Why choose a polyester cupboard rather than a metal one?

Résistance à la corrosion, aux UV et aux atmosphères agressives

In environments exposed to moisture, sea spray, chemicals or industrial pollution, metal casings can gradually deteriorate despite the anti-corrosion treatments applied.

Glass-fibre-reinforced polyester does not rust. Its corrosion resistance is inherent to the material, enabling the enclosure to maintain its performance over the long term without the need for major maintenance.

Europoly polyester enclosures also feature finishes suited to outdoor environments: protective gel coat, UV-resistant treatments, anti-graffiti coatings or specific colours depending on project requirements.

This durability is particularly sought after in wastewater treatment plants, industrial ports, road infrastructure, photovoltaic installations and chemical sites.

Electrical insulation and safety (Class II)

Polyester is a natural insulator.

Unlike metal enclosures, which require systematic earthing, a polyester enclosure can be designed with double insulation (Class II). This feature improves safety for personnel whilst simplifying certain wiring diagrams.

It also helps to prevent galvanic corrosion, which can occur when different metals come into contact in a damp environment.

Reduced weight, logistics and overall cost

For equivalent mechanical performance, a polyester enclosure is generally lighter than a steel or stainless steel solution.

This reduction in weight facilitates transport, handling and installation, particularly at hard-to-access sites, on photovoltaic rooftops or in complex technical infrastructure.

Over the entire life cycle of the installation, the absence of corrosion, reduced maintenance requirements and the durability of the material generally help to optimise the total cost of ownership.

Polyester enclosure or polyester cabinet: what are the differences?

The choice between a polyester enclosure and a polyester cabinet depends mainly on the volume of equipment to be housed, the level of accessibility required and the site’s operational constraints.

When should you choose a polyester enclosure?

A polyester enclosure is generally used to protect compact equipment such as:

• sensors;
• Remote management modules,
• automation systems;
• communication systems;
• small-scale electrical distribution systems

Its compact size makes it easy to install on a post, wall or existing structure, whilst offering the same benefits as a polyester enclosure: corrosion resistance, electrical insulation and excellent performance in outdoor conditions.

When should you choose a polyester wardrobe?

A polyester enclosure is suitable for installations requiring more internal space or a higher level of complexity.

It is commonly used for:

• the electricity distribution network;
• industrial automation systems;
• transport infrastructure;
• monitoring equipment;
• photovoltaic power stations;
• energy networks.

Design criteria

When choosing between a polyester enclosure and a polyester cabinet, the following factors should be taken into account:

• the required usable volume;
• maintenance requirements;
• the scalability of the installation;
• the required IP and IK ratings;
• regulatory constraints;
• environmental conditions.

Key criteria for choosing a polyester wardrobe

The choice of a polyester enclosure or cabinet must always begin with a detailed analysis of the conditions at the installation site. An enclosure that is perfectly suited to an indoor industrial environment will not necessarily meet the requirements of an outdoor installation exposed to the elements, UV radiation or corrosive atmospheres.

Installation environment

The first factor to consider is the actual site environment.

Europoly polyester enclosures are used in a wide variety of settings:

• wastewater treatment works;
• pumping stations;
• solar power stations;
• railway infrastructure;
• industrial ports;
• tunnels;
• chemical sites;
• petrochemical plants
• Energy networks

Each environment imposes specific constraints that directly influence the choice of materials, protection ratings and design options.

An outdoor polyester enclosure installed near a coastline will not be subject to the same harsh conditions as a polyester enclosure used in a food processing plant or an indoor plant room.

A preliminary site analysis helps to identify the associated risks:

• corrosion;
• moisture;
• salt spray;
• chemicals;
• dust;
• mechanical impacts;
• temperature variation.

IP and IK indices: what they mean in practice

The performance of a polyester cabinet is generally characterized by two essential indicators:

• IP indice (Ingress Protection) ;
• IK indice

The IP rating measures the envelope’s ability to protect equipment from dust and water ingress.

The IK index measures resistance to mechanical shocks according to standard EN 62262.

For the majority of outdoor industrial applications, an IP65 polyester cabinet combined with an IK10 resistance level is a particularly efficient solution.

An IP65 polyester box ensures:

• total protection against dust;
• protection against water jets from all directions.

The IK10 index corresponds to an impact resistance of 20 joules, suitable for environments exposed to the risk of accidental degradation or vandalism.

Thermal management: do not confuse sealing and insulation

A perfectly waterproof IP65 polyester cabinet is not necessarily suitable for all thermal constraints.

When the installation is exposed to the sun or when the integrated equipment releases a large power, the indoor temperature can quickly increase.

Conversely, some configurations can promote condensation during thermal variations between day and night.

To ensure the reliability of equipment, it may be necessary to integrate:

• filtered ventilation;
• specific grids;
• heat exchangers;
• an insulated sandwich construction.

Thermal management must be considered from the design phase in order to avoid costly corrective interventions after commissioning.

Outdoor polyester wardrobe: why has it become an industrial reference?

Outdoor polyester cabinets are now widely used in areas where metal enclosures reach their limits.

Thanks to glass fiber reinforced polyester, they offer excellent resistance:

• UV light;
• moisture;
• corrosive atmospheres;
• sea spray;
• chemicals.

Unlike conventional metal cabinets, they do not require periodic anti-corrosion treatment and retain their mechanical performance for many years.

This durability explains their growing presence in:

• wastewater treatment plants;
• ports ;
• transport infrastructure;
• photovoltaic installations;
• outdoor electricity networks.

For industrial operators, this translates into fewer maintenance operations and improved equipment availability.

IP65 polyester enclosure: how does it perform outdoors?

The IP65 polyester enclosure is one of the most sought-after configurations.

It provides effective protection for equipment against:

• dust
• splashes of water;
• Adverse weather conditions
• harsh industrial environments.

This combination of performance features is particularly well suited to outdoor installations requiring a high level of reliability.

IP65 polyester enclosures are used in particular for:

• photovoltaic equipment;
• monitoring systems;
• metering cabinets;
• industrial automation systems;
• road infrastructure;
• energy networks.

When combined with IK10 impact resistance, an IP65-rated polyester enclosure often offers the best balance between protection, durability and overall cost.

Comparison: polyester cupboards vs metal cupboards

Criterion	Polyester cupboard	Painted or galvanised steel cupboard	Stainless steel cupboard
corrosion resistance	excellent	Depends on the surface	good
Electrical insulation	Class II possible	Earthing is compulsory	Earthing is compulsory
Weight	Lightweight	Medium	High
Maintenance	Very low	regular	Low
Durability in an aggressive environment	Very high	Variable	good
Total cost over time	Optimised	May rise rapidly	Higher
Customisation	Very high	Average	Limited

In most corrosive environments or those subject to severe weather conditions, polyester enclosures now offer one of the best balances between safety, durability and overall cost.

Applications of industrial polyester cabinets and enclosures

Polyester cabinets and enclosures are used in many industrial sectors where the reliability of equipment is of critical importance.

Sewage treatment works and water treatment

Damp and corrosive environments make glass-fibre-reinforced polyester a particularly suitable solution for water treatment plants.

Photovoltaics and renewable energy

Polyester photovoltaic enclosures combine UV resistance, Class II electrical insulation and a high IP rating.

They are ideally suited to the requirements of solar power stations and renewable energy infrastructure.

Chemical and petrochemical industry

Environments with high levels of chemical agents require enclosures capable of withstanding corrosion over the long term.

Glass-fibre-reinforced polyester offers a major advantage here over conventional metal solutions.

Industrial ports and marine environments

Salt spray significantly accelerates the deterioration of metal enclosures.

Outdoor polyester enclosures help to limit this phenomenon whilst reducing maintenance requirements.

Rail and road infrastructure

Signage, monitoring, electrical distribution, metering or safety equipment: polyester enclosures and cabinets are widely used in transport infrastructure.

Electricity networks and street lighting

Polyester is particularly valued for equipment requiring high reliability and excellent resistance to harsh weather conditions.

Europoly ranges of polyester cabinets and enclosures

With over twenty years’ experience in the design of composite enclosures, Europoly offers a comprehensive range of polyester enclosures, polyester cabinets and technical enclosures designed for the most demanding industrial environments.

Polyester enclosures and small cabinets

The Micro Euro and Mini Euro ranges are designed for compact applications requiring a high level of protection against external influences.

These polyester cases are particularly suitable for:

• decentralised control systems;
• to the sensors;
• remote management systems;
• water networks;
• to metering installations;
• small-scale technical infrastructure.

Their compact design makes them easy to install on walls, posts or existing structures, whilst retaining the mechanical and anti-corrosion properties of glass-fibre-reinforced polyester.

Euro Medium modular polyester cabinets

The Euro Medium range meets the needs of standard industrial installations requiring more space and modularity.

Available in different configurations IP55 to IP65 and IK10, these polyester cabinets allow the integration of:

• editing plates ;
• electrical equipment;
• industrial automation;
• communication systems;
• 19-inch chassis;
• specific technical compartments.

They are commonly used in the water treatment, transport infrastructure, energy and industrial sectors.

Large polyester cabinets: Maxi Euro 1500 and Maxi Euro 1900

The Maxi Euro 1500 and Maxi Euro 1900 ranges are intended for demanding outdoor applications requiring a large useful volume.

These outdoor polyester cabinets benefit in particular:

• a high protection factor;
• with a mechanical resistance IK10;
• an anti-UV gel coat;
• an integrated awning;
• excellent resistance to aggressive environments.

They are particularly suitable for electrical distribution stations, photovoltaic installations, supervision equipment and rail or road infrastructure.

Specialized cabinets: photovoltaic, high voltage, and industrial analysis

Some applications require specific developments.

Europoly designs dedicated polyester cabinets:

• photovoltaic power plants;
• to the ENR infrastructure;
• to high-voltage installations;
• to the industrial analysis equipment;
• to ATEX applications;
• at the technical shelters.

Depending on the constraints of the project, different manufacturing technologies can be used: SMC, contact molding or RTM.

Custom-made polyester wardrobe: when the standard is no longer enough?

While the standard ranges meet most industrial needs, some applications require a specific design.

A bespoke polyester cabinet may be considered where the project requires:

• specific dimensions;
• a specific compartmentalisation;
• a specified RAL colour;
• non-standard equipment;
• ATEX requirements;
• specific regulatory requirements;
• the integration of complex systems.

Thanks to its design office and its various manufacturing processes, Europoly supports manufacturers in developing solutions tailored to the most demanding technical requirements.

How to choose the right size for your polyester wardrobe: four questions to ask before making your choice

1. What are the actual site conditions?

Before making any selection, it is important to identify precisely:

• exposure to the elements;
• the presence of moisture;
• the risk of corrosion;
• chemical agents;
• sea spray;
• mechanical stresses.

These factors directly influence the choice of material and the level of protection required.

2. What IP and IK ratings are required?

Specifications often stipulate specific levels of protection.

In most cases, an IP65 IK10 polyester enclosure effectively withstands outdoor industrial conditions, but certain applications require enhanced protection.

3. Are there any thermal constraints?

Constant exposure to sunlight, equipment that generates a lot of heat, or significant temperature fluctuations may require specific solutions:

• filtered ventilation;
• enhanced insulation;
• heat exchange;
• sandwich construction.

Anticipating these constraints helps to ensure the long-term reliability of the system’s performance.

4. Is a standard solution sufficient?

When project requirements exceed the capabilities of standard ranges, a bespoke polyester enclosure provides a solution that is perfectly tailored to operational requirements.

How much does a polyester cupboard or polyester cabinet cost?

The price of a polyester cupboard depends on a number of factors:

• dimensions ;
• IP index
• IK impact resistance;
• built-in equipment;
• level of customisation;
• regulatory constraints;
• installation environment.

Similarly, the cost of a polyester enclosure varies depending on its internal volume, its protection rating and its configuration options.

Beyond the initial purchase cost, it is essential to assess the total cost of ownership. In harsh environments, the durability of glass-fibre-reinforced polyester often leads to a significant reduction in maintenance costs compared with certain metal solutions.

Polyester wardrobes: what you need to know before choosing one

The choice of a polyester cabinet or a polyester enclosure should always be based on the actual site conditions.

Thanks to its corrosion resistance, natural electrical insulation, light weight and durability, glass-fibre-reinforced polyester is now the go-to solution for many industrial applications.

Whether it is a photovoltaic installation, a wastewater treatment plant, an industrial port, railway infrastructure or a chemical environment, polyester enclosures offer an excellent balance between safety, durability and overall cost.

With its standard product ranges and bespoke development capabilities, Europoly supports manufacturers in designing technical enclosures suited to the most demanding environments.

If your project involves specific constraints or a particularly harsh environment, our technical teams can help you identify the most suitable solution.

FAQ – Frequently asked questions about polyester cabinets and enclosures