Understanding Ingress Protection and Why Installations Fail in the Field

In industrial and mining environments, electrical equipment failure rarely happens because the spec sheet was wrong — it happens because the real-world conditions were harsher than anticipated, or the installation compromised the enclosure’s integrity. 

As South Africa enters the rainy season, humidity, wind-driven rain, dust storms and thermal cycling expose luminaires to some of the most aggressive ingress conditions of the year. This is when IP ratings are put to the real test — and when even “IP66” installations can fail unexpectedly. 

To understand why, we need to look beyond the numbers and into the science behind ingress protection.

What IP Ratings Actually Mean (And What They Don’t)

IP (Ingress Protection) ratings are defined in IEC 60529. An IP rating has two digits:

• First digit (0–6): Dust and solid ingress protection

• Second digit (0–9): Water ingress protection

Examples:

• IP65 – Dust-tight, protected against low-pressure water jets

• IP66 – Dust-tight, protected against powerful water jets

• IP67 – Dust-tight, protected against temporary immersion

• IP68 – Dust-tight, protected against prolonged immersion (conditions defined by manufacturer)

The problem:

People often assume that a higher number is always better for all applications — which is not true. IP67/IP68 may sound superior, but sometimes, immersion-rated fittings can perform worse than IP66 in high-pressure washdowns or thermal-cycling environments.

How Water Actually Enters a Luminaire

Even a fully-certified IP66 enclosure can fail if:

• Gaskets are compressed incorrectly

• Cable glands are overtightened or under tightened

• Breathers are blocked

• Seals degrade due to UV or chemicals

• Incorrect cable diameter is used in the gland

• Water enters via capillary action along cable sheathing

• The luminaire body is compromised during installation

IP failures could sometimes occur, not because the luminaire was poorly designed, but because the installation created a path for water, such as drilling or not following installation instructions.

IP Testing: What Happens in the Lab

Manufacturers test their enclosures under controlled conditions:

IP65 Test

• Low-pressure water jets (6.3mm nozzle)

• 12.5 L/min (±5%)

• 3m distance

IP66 Test

• High-pressure water jets (12.5mm nozzle)

• 100 L/min (±5%)

• 3m distance

IP67 Test

• Immersion at 1m for 30 minutes

IP68 Test

• Prolonged immersion at a specific depth and duration (manufacturer-defined)

Here’s the catch: Lab testing is static. Sites are not.

Real installations deal with wind-driven rain, temperature changes, cable movement, UV degradation and vibration — all of which lab testing sometimes fail to replicate.

IP65 vs IP66 vs IP67 — Clearing the Misconceptions

Myth 1: IP67 is “better” than IP66 

Not always. IP67 protects against immersion, but it is not tested or designed for:

• High-pressure washdowns

• Continuous water jets

• Angled spray from height

• Wind-driven mist

In mines and plants, IP66 is often the more appropriate choice because high-pressure water jets are common.

Myth 2: “Dust-tight” means maintenance-free Even IP66 fittings require:

• Periodic cleaning

• Checking cable gland integrity

• Inspecting UV fatigue

• Confirming breather plugs aren’t obstructed

Dust management is an ongoing process, not a one-time rating.

Myth 3: Higher IP means better thermal performance 

Actually, the opposite is often true. Tightly sealed enclosures dissipate heat less effectively than ventilated ones — leading to accelerated component degradation if the fixture’s thermal design is poor.

Why IP-Rated Luminaires Fail in the Field

Here are the most common reasons behind real-world failure:

• Incorrect Cable Gland Selection A luminaire can be IP66, but the cable gland can drop it to IP54 if the wrong size or type is used.

• Over-Tightening Glands and Gaskets Crushed seals allow water ingress during thermal expansion cycles.

• Vibration Loosening Mining and plant equipment induces vibration — tiny gaps can form over time if the luminaire is not designed to withstand vibration.

• Missing or Blocked Breathers Pressure equalisation valves prevent vacuum suction that pulls water in during cooling cycles.

• Chemical Attack on Seals Certain hydrocarbons, solvents and cleaning agents degrade silicone gaskets prematurely.

• Poor Installer Training Most ingress failures occur after installation, not during manufacturing.

Best Practices for Engineers and Installers

Choose the right IP rating for the environment

• IP66for washdown areas, heavy rain, outdoor industrial

• IP67/IP68for short-term or long-term immersion

• IP65for sheltered outdoor use and areas with only low pressure water contact

Specify certified cable glands Look for:

• IP66/67 rating

• Proper compression seal

• UV and chemical resistance

Inspect annually Visually inspect for clear damage to the luminaire that could lead to water ingress, this includes chemical and UV damage.

Protect against chemical exposure Carefully select luminaire materials in chemically hazardous areas to avoid chemical reactions that may damage important IP rated components.

Never block breather plugs Breathers release internal pressure and prevent vacuum draw during cooling.

Use thermal modelling Especially when specifying sealed fittings in hot ambient conditions.

Magnitech’s Approach to Ingress Protection

Magnitech luminaires are engineered to outperform under real industrial conditions, not just laboratory tests. Our IP-rated fittings deliver:

• IP66 sealed enclosures using closed-cell silicone gaskets

• Marine-grade aluminium housings with corrosion-resistant finishes

• Proper thermal pathways to prevent heat buildup

• Trialled and tested weather proof glands

• Optional breathing valves for high-temperature applications

• Full compliance with IEC 60529 and relevant SANS standards

We design for the environment, not the catalogue.

Conclusion

IP ratings are a starting point, not a guarantee. Water, dust and electrical systems do not forgive poor installation, incorrect component pairing or inadequate thermal design. 

As the rainy season intensifies, engineers and installers must treat ingress protection as a complete system — luminaire + gland + gasket + orientation + environment — working as one.

And when reliability matters, specifying a luminaire built for real-world abuse is the only option. 

If you need support selecting or validating IP-rated fittings for your site, Magnitech’s engineering team is here to help.