Reliable Connections for Harsh Environments

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Connectors are often overlooked components in industrial systems. Although connectors may seem trivial in equipment worth millions, their impact far exceeds their cost. This impact becomes painfully obvious when connectors fail. In a recent HelioVolta study conducted for the solar energy industry, more than 80 percent of installations were suffering from connector-related faults.^[1] Nearly half of these sites needed urgent intervention to correct the faults, with a few serious enough to force a complete shutdown.

In this blog, we reveal the understated value of connectors by looking closely at the risks posed by connector failures and examining connector solutions that ensure reliability across industrial systems.

The Challenge of Reliability

While the HelioVolta study focused on renewable energy, its findings illustrate how critical connectors are to modern installations. The key lesson for connector users is that most of the faults discovered were entirely preventable.

Connector selection is more critical than ever as modern equipment becomes increasingly exposed to harsh environmental conditions. Smart agriculture, distributed energy resource systems, and the growing demand for wireless and satellite communications mean that sophisticated equipment is deployed far beyond the protected confines of the factory floor.

Connectors are at the frontline of industry. They deliver power, data, and signal in demanding conditions, including vibration, the presence of dust and moisture, and even exposure to UV radiation in sunlight. These environmental factors can cause active failure modes when connectors are poorly designed or incorrectly installed. In these circumstances, choosing the right ruggedized solutions is critical to overall system performance.

Understanding IP Ratings for Waterproof Connectors

While standardized connectors are important tools in the designer’s repertoire, the connectors they choose do not have to be standard in their quality. The ingress protection (IP) rating system assists designers when choosing the right component. The code is simple in its concept: the first digit denotes the level of protection against solid objects, while the second digit defines the protection against the ingress of water (Figure 1). For both digits, the higher rating correlates to increased protection.

This rating system acts as a shorthand to ease the component selection process. For designers requiring a waterproof connector, IP67 and IP68 ratings are the most common, but the difference between them is significant.

Figure 1: Breakdown of IP ratings for solid foreign object and water ingress protection. (Source Mouser Electronics)

For many applications, IP67 is sufficient. This level of protection is suitable for equipment mounted in exposed conditions, but it is not designed for situations that require long-term water immersion. IP67-rated connectors are tested to withstand immersion in water up to 1 meter in depth for a duration of up to 30 minutes, as specified in IEC 60529. This is critical, as water pressure increases rapidly with depth and the waterproof seals used in IP67 connectors are not designed to withstand prolonged exposure to these conditions.

If a component is expected to be immersed to a greater depth, or for longer periods of time, the design of the waterproof seals must reflect the increased pressure they will face. These are the conditions defined by IP68—prolonged immersion in water to depths greater than 1 meter. The exact duration is typically published by the manufacturer following intensive testing, but the important implication is the effect this performance has on design.

Creating a connector that is truly IP68 compatible requires changes to its design that also affect its cost. Choosing the right connector for each application requires a complete understanding of the conditions the equipment must operate within. For applications where deep or prolonged water immersion are not the operating conditions, there is no need to choose an expensive IP68 solution. The design choice must be appropriate for the environment.

Connector Mating and Installation Failures

Even the most expensive connector is useless if used incorrectly. Water damage is estimated to contribute to 20 percent of electronic failures,^[2] and connectors represent a key weakness if not properly installed. Achieving the desired level of protection depends on correct mating. Manufacturers publish detailed instructions for the use of their products, and it is essential that these are followed.

Mating connectors can seem simple, but it is not always as straightforward as it appears. Threaded connectors rely on the right alignment to maintain a reliable seal, and even a small oversight can cause a big problem. Before connecting, it's important to check for dirt, debris, or even a worn O-ring, since these seemingly minor issues can lead to failure once the system is powered up.

In many systems, certain connectors remain unmated during normal operations, such as charging cables for handheld devices or rarely used data links. A little-understood feature is that many connectors are only waterproof when mated. When left unmated, their ingress protection can be compromised unless equipped with sealed housings or protective caps.

Stewart Connector M-Series Solution

Selecting the right connector requires matching performance to the equipment’s operating environment. The M-Series of industrial connectors from Stewart Connector is specifically engineered to deliver reliable service in demanding conditions.

For compact or space-constrained designs, the M5 A-coded connectors and cables provide a sealed, robust interface that is ideal for small sensors or embedded devices. These connectors are suited for densely packed designs, either on a small PCB or inside confined housing. In these scenarios, saving board and enclosure space is important to fit other components. The M5 connectors offer sealing and vibration resistance to keep operations reliable and durable, without sacrificing one for the other.

For applications that demand more flexibility, the M8 series is an appropriate choice (Figure 2). Available in A-coded variants, these connectors support signal, data, and low-current power in mobile systems, industrial panels, and distributed control units. The M8 is also available with metal dust caps to provide the all-important sealing when left unmated.

Figure 2: The M8 connectors for industrial applications and harsh environments. (Source: Mouser Electronics)

The popular M12 series is equipped for more demanding installations that require higher data throughput or power capacity. The D-coded variants are used for Ethernet and data applications in industrial automation and smart factories, while K-coded connectors offer high-current capacity for actuators, motors, and power delivery in rugged equipment. M12 connectors combine mechanical strength with ingress protection to deliver reliability in challenging outdoor or high-vibration environments.

All Stewart Connector M-Series products are IP-rated, providing consistent environmental protection across the entire portfolio. This gives designers the flexibility to build modular, scalable systems without compromising reliability.

Conclusion

Connector failures cause operational and safety issues out of proportion to their cost. What’s more concerning is that many of these failures are preventable.

At the earliest stages of product development, connectors must be considered as a core component. Choosing a connector that matches the application and ensuring its performance under demanding conditions will prevent many failures.

However, it is important to remember that even the strongest system is only as strong as its weakest link. The dangers of mis-mating or poor connector maintenance are just as high as poor component choice. Understand your application and choose your connector wisely.

[1]https://www.heliovolta.com/resources/connector-white-paper
[2]https://ieeexplore.ieee.org/document/5422477

David Pike is well known across the interconnect industry for his passion and general geekiness. His online name is Connector Geek.