Anti-humidity boxes: are IP boxes waterproof?

One anti-humidity case is often associated with a IP65+ waterproof electrical box. But do these indicators really guarantee protection against the entry of air and water vapor?

The question is essential to prevent the condensation in an electrical box and ensure a good humidity control.

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Are IP boxes airtight?

IP-classified devices meet the international standard IEC 60529 (IEC 60529), which defines the levels of protection against:

• The intrusion of solid bodies (dust),
• The penetration of liquids (water).
  
  

This standard does not guarantee gas tightness. It therefore does not protect against the entry of air or water vapor. One IP waterproof housing can be protected against liquid water... while gradually allowing moisture to pass through the air.

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Why is it a problem?

In a outdoor electrical box, room humidity may penetrate slowly.

If the temperature drops and reaches the Dew temperature, we can observe:

• Humidity by condensation,
• Corrosion of components,
• Degradation of connections,
• Electrical hazard.
  
  

A simple waterproof connection box is therefore not always sufficient to guarantee protection against internal condensation.

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Experimental protocol

In order to assess the actual airtightness, we conducted a laboratory study.

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Cases tested

• 1 IP65 waterproof housing
• 1 IP67 waterproof housing
  
  

These two types are commonly used as:

• outdoor waterproof electrical box,
• waterproof electrical connection box,
• Electronic sensor housing
• Network box
• Charging stations
  
  

Methodology

At room temperature (22°C), approximately 40% ofRelative humidity):

• One humidity sensor is placed in each case,
• The boxes are closed,
• They are then placed in a climate chamber at:
  
  
  
  • 30°C,
  • 84% relative humidity.

This configuration makes it possible to observe the evolution:

• From the internal temperature,
• Relative humidity,
• From the concentration of water vapor.
  
  

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Results

Thermal evolution

The internal temperature of the boxes converges with that of the enclosure.

Stabilization time: ≈ 1.6 hours (100 minutes).

This shows that the thermal inertia of waterproof electrical boxes is significant.

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Humidity evolution

In both cases:

• The water concentration is increasing sharply,
• Internal relative humidity is increasing,
• Neither case is airtight.

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Difference between IP65 and IP67

IP67 housing

• Rapid increase in water concentration at the beginning,
• Stabilization after a few hours.
  
  

Interpretation:
When the case is heated, the internal air expands.
This overpressure temporarily causes the seals to fail.

Air intake seems to be mainly linked to temperature variations.

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IP65 housing

• Continued increase in water concentration,
• Slower progression after thermal stabilization,
• Lack of airtightness even at constant temperature.
  
  

Ce electrical box is therefore not hermetic to gas exchange.

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An IP box is not an anti-humidity box

The tests show that:

• The IP65 and IP67 boxes are not airtight,
• They gradually become loaded with moisture in the air,
• A risk of condensation in an electrical box exists in case of cold spots.
  
  

One anti-humidity case therefore requires:

• Or an active system (electrical moisture absorber),
• Let it be a passive moisture absorbent such as the So Sponge AS-B tape,
• That is, a specific hygrometric control solution.

The IP rating protects against liquid water and dust, but not againstAmbient humidity.

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The AS-B tape: passive protection against condensation

The AS-B tape is a solution developed by Sosponge to sustainably protect:

• waterproof electrical boxes,
• Electrical connection boxes,
• Outdoor electrical boxes,
• Sensitive electronic boxes.
  
  

A simple solution to integrate

AS-B tape comes in adhesive form:

• Fast installation,
• No maintenance,
• No drilling of the case,
• Compatible with IP waterproof boxes.
  
  

It transforms a simple outdoor waterproof electrical box in a truly optimized solution against internal humidity.

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Protect your equipment sustainably

If your equipment is exposed to:

• Significant climate variations,
• Humid environments,
• Repeated thermal cycles,

The AS-B tape is an effective solution to limit electrical box condensation and extend the life of components.

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