Choosing an electrical cabinet is not simply a matter of selecting an IP rating or a material. Behind the choice between a ventilated and a sealed electrical cabinet lies a much broader issue: ensuring the reliability of the installation over many years despite environmental constraints.
Humidity, dust, heat emitted by equipment, corrosive atmospheres, and significant temperature variations directly influence the performance of an electrical cabinet. A poor choice can lead to component overheating, condensation, premature corrosion, or costly maintenance.
This is why polyester enclosures have become a preferred solution in many industrial sectors. Thanks to their natural corrosion resistance, excellent electrical insulation, and mechanical robustness, they perfectly meet the requirements of outdoor installations or harsh environments.
But should you choose a completely airtight cabinet or a ventilated one? The answer depends less on the product itself than on the actual constraints of your project.
In this guide, we help you make the right choice based on your environment, your thermal balance and the expected IP/IK protection level.
First and foremost: understand the criteria that influence the choice of a polyester wardrobe
Ventilated cabinets are often contrasted with sealed cabinets. However, this opposition is simplistic.
The real objective is to find the best balance between:
- protection against external aggression;
- managing the heat produced by the equipment;
- the control of condensation;
- ease of maintenance;
- the lifespan of the installation.
A perfectly sealed cabinet is not necessarily the best solution, just as a ventilated cabinet is not suitable for all environments.
Before comparing these two approaches, it is essential to understand the concepts of IP index, IK index and the specificities of polyester.
IP and IK ratings: the basis of proper sizing
The IP and IK ratings define the level of protection of an electrical enclosure.
The IP (Ingress Protection) rating indicates resistance to the penetration of solid objects and liquids.
For example :
| Hint | Level of protection |
|---|---|
| IP54 | Protects against dust and water splashes |
| IP55 | Protects against water jets |
| IP65 | Completely dustproof and protected against water jets |
| IP66 | Protected against powerful water jets |
The IK index , meanwhile, measures resistance to mechanical shocks.
An IK10 cabinet can withstand an impact of 20 joules, making it particularly suitable for outdoor installations, road infrastructure, or sites exposed to vandalism.
Why polyester has become the standard in harsh environments
The choice of material is often more important than the choice of IP rating.
A metal cabinet can display an excellent protection rating while gradually degrading under the effect of corrosion.
Conversely, a fiberglass-reinforced polyester wardrobe offers several advantages:
- excellent resistance to saline environments;
- corrosion resistance;
- very good electrical insulation (class II);
- low thermal conductivity;
- excellent UV resistance;
- Reduced maintenance.
These qualities explain why polyester wardrobes are now widely used in:
- water treatment plants;
- chemical sites;
- ports ;
- road infrastructure;
- electrical networks;
- photovoltaic installations.
Good to know
A high IP rating protects against water ingress, but it does not protect against corrosion of the material. Therefore, the choice of enclosure remains crucial.
Waterproof electrical cabinet: the best solution against external damage?
A sealed electrical cabinet is designed to prevent the ingress of dust, water, and contaminants.
It is often the most relevant solution when equipment is directly exposed to the elements or particularly aggressive environments.
The main advantages of a waterproof cabinet
An IP65 or IP66 polyester enclosure effectively protects equipment against:
- the driving rains;
- splashes of water;
- industrial dust;
- sea spray;
- chemical products.
It naturally finds its place in:
- pumping stations;
- wastewater treatment plants;
- port facilities;
- petrochemical sites;
- outdoor electrical substations.
Thanks to its sealed casing, it greatly reduces the risk of contamination of electrical components.
Condensation: an often underestimated risk
A common mistake is to think that a perfectly sealed cabinet will never encounter moisture problems.
In reality, condensation very often comes from… the inside.
When the temperature drops rapidly, the air inside the cabinet cools down.
The moisture it contains then transforms into droplets that settle on the electrical components.
The consequences can be significant:
- terminal block corrosion;
- oxidation of connections;
- insulation defects;
- untimely triggering;
- reduction in equipment lifespan.
Common mistake
The more airtight a cabinet is, the more limited the air exchange with the outside. Without a suitable thermal strategy, this can exacerbate condensation.
When is it best to choose a waterproof polyester wardrobe?
A waterproof cabinet is generally recommended when:
- the installation is located outdoors;
- the environment is highly corrosive;
- the equipment produces little heat;
- Water splashes are frequent;
- Dust is important.
In these situations, it is often preferable to add an anti-condensation resistor rather than opening the cabinet using conventional ventilation.
Ventilated electrical cabinet: an effective solution to thermal constraints
Not all cabinets face the same problems.
In some projects, the main risk isn’t water, but the heat generated by the equipment. Variable speed drives, power supplies, PLCs, converters, and power electronics can dissipate several hundred watts within a single enclosure. Without air circulation, the temperature rises rapidly, reducing component performance and accelerating aging.
A ventilated cabinet allows this heat to be evacuated while maintaining a more stable operating temperature.
Why ventilate an electrical cabinet?
The main purpose of ventilation is to remove the heat produced by electrical components in order to maintain a temperature compatible with their operation.
It is particularly relevant when:
- the cabinet contains several speed controllers;
- Power supplies or converters dissipate a significant amount of power;
- the automated systems operate continuously;
- The installation is located in an enclosed technical room.
By promoting air renewal, properly sized ventilation limits hot spots and improves the lifespan of equipment.
In this type of configuration, a ventilated polyester cabinet offers an excellent compromise between protection, thermal performance and ease of maintenance.
What impact on the IP index?
This is a point that is often misunderstood.
Adding a fan, filter grille, or opening automatically changes the overall protection level of the cabinet.
For example :
- An IP66 cabinet equipped with an IP54 filter grid will no longer be considered IP66;
- Its overall protection rating will be reduced to the level of the least efficient component.
This rule is directly linked to the NF EN 60529standard .
This does not mean that a ventilated cabinet offers less protection. However, it should be reserved for environments compatible with this level of protection.
Indoors, an IP54 or IP55 rating is generally sufficient.
Outdoors, it is advisable to prioritize solutions incorporating protective covers, specific fans or suitable cooling systems.
Natural ventilation, fan or air conditioning: which solution to choose?
Not all installations require an industrial air conditioner.
The choice depends primarily on the power dissipated.
| Thermal demand | Recommended solution |
|---|---|
| Low dissipation | Natural ventilation |
| Average dissipation | Filtered fan with thermostat |
| High dissipation | Air-to-air or air-to-water heat exchanger |
| Very high dissipation | Industrial air conditioner |
In all cases, it is preferable to carry out a thermal assessment during the design phase in order to choose a suitable solution rather than correcting a problem once the installation is in service.
Ventilated or airtight cabinet: how to make the right choice?
Rather than pitting two solutions against each other, it is better to analyze the main risks that your installation will face.
First criterion: the environment
Ask yourself the following questions:
- Will the cabinet be installed indoors or outdoors?
- Is the site exposed to sea spray?
- Is there a chemical risk?
- Is the environment dusty?
- Are the facilities accessible to the public?
If the answer is yes to several of these questions, a waterproof polyester cabinet is generally the best option.
Second criterion: power dissipation
Thermal analysis is essential.
Add up the power dissipated by the different pieces of equipment
- variable speed drives:
- Power supplies;
- automata;
- converters;
- power electronics.
The greater the power output, the more a cooling strategy will need to be considered.
Third criterion: the risk of condensation
Condensation remains one of the primary causes of failure in cabinets installed outdoors.
It appears particularly when:
- The temperature variations are significant;
- The ambient humidity is high;
- the cabinet is completely closed;
- No regulatory device is installed.
Depending on the circumstances, several solutions can be combined:
- anti-condensation resistance;
- thermostat;
- hygrostat;
- controlled ventilation;
- heat exchanger.
Decision support table
| Your environment | Recommended solution |
|---|---|
| Water treatment plant | Polyester enclosure IP65/IP66 + anti-condensation resistance |
| Chemical industry | Waterproof polyester cabinet IP66 IK10 |
| Indoor technical room | IP54/IP55 ventilated polyester cabinet |
| Outdoor electrical substation | IP65 polyester enclosure with thermal management |
| Tunnel or road infrastructure | IK10 polyester cabinet with reinforced protection |
| Photovoltaic park | IP65 polyester enclosure suitable for climatic variations |
Key points to remember
The choice is never simply a matter of “ventilated or airtight”. The best solution is one that combines the right material, the right IP/IK rating, and a thermal strategy adapted to the environment.
Why polyester cabinets remain the best choice in the majority of industrial projects
Beyond the issue of ventilation, the real factor in durability remains the material of the envelope.
In modern industrial environments, polyester cabinets offer several decisive advantages
- excellent corrosion resistance, even in saline or chemical environments;
- natural electrical insulation (class II);
- low thermal conductivity limiting temperature variations;
- high resistance to UV and aging;
- reduced maintenance compared to metal cabinets.
Depending on the needs, the Europoly ranges can cover the majority of applications :
- Micro Euro and Mini Euro for compact IP66 IK10 enclosures;
- Euro Medium for electrical panels and automation systems;
- Maxi Euro for large capacity outdoor cabinets;
- Mega Euro for technical cabins and infrastructure.
Frequently Asked Questions
An IP54 cabinet protects against dust and water splashes, while an IP65 cabinet is completely dustproof and resistant to water jets.
Yes, provided that suitable components are used (protected grilles, covers, specific ventilation) and that an overall IP rating lower than that of a completely sealed cabinet is accepted.
Installing an anti-condensation heater, a humidistat or a thermal regulator can effectively limit this phenomenon.
Polyester is naturally corrosion-resistant, offers excellent electrical insulation, and requires less maintenance in harsh environments.
Yes. Polyester cabinets intended for outdoor use are designed to retain their mechanical properties despite prolonged exposure to the sun.
When the power dissipated is significant and simple ventilation is no longer sufficient to maintain the operating temperature of the equipment.
Conclusion
Choosing between a ventilated electrical cabinet and a sealed electrical cabinet is not about opposing two technologies, but about responding to the real constraints of your installation.
The environment, thermal power, risk of condensation, IP/IK protection level and enclosure material must be studied together to ensure the long-term reliability of the equipment.
In most outdoor, corrosive or highly exposed environments, polyester enclosures are now a particularly effective solution thanks to their natural resistance to corrosion, electrical insulation and durability.
To define the most suitable configuration for your project, it is recommended to carry out a complete analysis of the environment, the thermal balance and the protection requirements before any equipment selection .