Can Liquid Cooling Cable Glands Meet IP68 Waterproof Requirements?
While liquid cooling cable glands can be rated for IP68 waterproof protection, they are only able to achieve this if the gland’s design, sealing method, materials, installation practices and test procedures are matched to the actual working conditions.
In high-powered systems where coolant, cables, pressure, vibration and heat exist together, a standard waterproof cable gland may not be adequate. Therefore, the appropriate solution must provide reliable sealing, mechanical strain relief, corrosion resistance and long-term stability under continuous thermal cycling.
Liquid cooling is not just a niche technology anymore. Data centers, Energy Storage Systems (ESS), Electric Vehicle (EV) Charging Equipment, Power Electronics, Medical Devices, and Industrial Automation, all require liquid coolers due to the higher density of heat produced by today's technology. Air cooling may no longer be able to provide sufficient cooling to effectively dissipate the heat generated by these technologies due to the high thermal loads. Liquid cooling cable glands or connectors are designed to minimise the risk of overheating, coolant leaking, electrical failure and unplanned downtime. In this document you will learn how IP68 rated Liquid Cooling cable glands work, what materials should be used, how they compare with quick-disconnect fittings and what every buyer should look for when selecting a potential supplier.
What Does IP68 Mean for Liquid Cooling Cable Glands?
IP68 has been defined through the ingress protection classification of IEC 60529. Dust tightness is indicated as “6”, and the ability for the enclosure to withstand water for a certain amount of time is indicated as “8”. In the case of a typical IP68 cable gland, any water or coolant would not be allowed to enter into the enclosure through the cable entry point due to extended exposure to water or coolant.
Though IP68 (ingress protection) is not an absolute test condition across all devices; one manufacturer may validate their product by testing it for 30 minutes at 1 meter of water, while another could use 2 meters of water for a maximum test duration. When evaluating liquid cooled systems, buyers need to verify the following: The actual testing/depth used to determine the product's ability to withstand moisture; the total length of testing; the temperature at which the tests were conducted; the cable size that was used for the testing; and if the product is compatible with the type of coolant used in the fluid-cooled system/assembly.
Water-resistant designs are part of the challenge of liquid-cooled equipment; however, they must also operate well under internal pressure and exposure to coolant, as well as withstanding repeated heat/cooling cycles and constant movement from the cable. Even though an item has passed a basic waterproof test, this does not necessarily mean it will still function properly in a real-world application, especially if the sealing ring has swollen, threads have loosened, or there is inadequate compression in the jacket of the cable.
Why Liquid Cooling Cable Glands Matter in High-Power Systems
Liquid cooling systemsare specifically designed to quickly transfer heat from critical components efficiently and rapidly. While a cable gland may seem like a small accessory, it is designed to protect one of the weakest points in the liquid cooling system; the location where cables come through a sealed enclosure and into the cold plate, CDU, server rack, and/or battery cabinet.
There are numerous problems that can be caused by improper sealing of this interface, such as: coolant leakage into an electrical compartment; moisture entering the enclosure; loose cables due to vibration; reduced sealing force caused by thermal expansion over time. In applications including AI servers, HPC, EV fast charging and energy storage, even minor leaks can lead to costly repairs or potential safety hazards.
A qualified liquid cooling cable gland provides three essential functions at the same time: waterproof sealing, strain relief, and mechanical protection. In demanding systems, it should also offer chemical resistance, corrosion resistance, and stable performance across a wide temperature range.
Can a Liquid Cooling Cable Gland Really Be Leak-Proof?
A properly designed and installed liquid-cooled cable gland can have very high resistance to leaking, but it should always be understood that they are "leak proof" only for specified or defined working conditions. Examples of those conditions would be: type of coolant used; operating pressure; outside diameter of the cable; thickness of the enclosure; installation torque being used; temperature; level of vibration; and length of service expected.
Liquid cooling connectors that are reliable and leak-proof typically have multiple seals for better performance and fewer issues. For instance, a sealing ring of rubber is placed inside the cable; there is an O-ring between the body of the gland and the panel; there are precision threads; and there is a compression nut that provides uniform pressure to each connection. The material of the female connector's housing can be made out of either stainless steel or brass, which provide additional strength and sturdiness of the threaded connections. Nylon has properties that make it lighter than metal, and it insulates; therefore, a nylon connector may be beneficial in certain electrical application where weight, or cost are concern(s).
The gland must be matched to the actual cable and system design in order to achieve maximum performance. The sealing insert will not be able to compress correctly if the cable is too small. Conversely, if the cable is too large, it can cause damage and/or deformation of the sealing ring during installation. Therefore, most professional suppliers have a recommended cable diameter range for each gland size.
Key Design Features of an IP68 Liquid Cooling Cable Gland
In order to fulfil the requirements of IP68 in an immersion cooling environment. The cable gland needs to be designed as a complete seal rather than a just a mechanical fit. All of the components i.e. Gland body, nut, sealing insert, o-ring, thread & cable interface will affect the final performance of thecable gland.
A key attribute of a good seal is the use of high quality elastomeric seals. These materials have a variety of temperature and chemical resistance properties, so common sealing materials are EPDM, FKM, NBR and Silicone, with each type having differing temperature or chemical resistances applicable to different operating environments. When using a water glycol coolant, EPDM is usually the preferred material due to its excellent resistance to water and water-based fluids, while FKM may be preferred when using oil or other more aggressive fluids. Ultimately, the right choice will depend on both the formulation of the coolant and its operating temperature.
The precision of threads is important as poorly machined threads can cause uneven compression, weak mechanical retention, or create possible leakage paths. Nickel plated brass and stainless steel are commonly used for Metal Cable Glands. Stainless steel fittings for liquid cooling applications are better when used in corrosive locations, outdoors, at sea, or in cleanrooms where long-term durability is required.
Strain relief is another critical feature. Liquid-cooled systems may be subjected to vibration from several sources, including pumps, fans (used across numerous different industries), and various pieces of large equipment such as automotive or other industrial machinery. Transmitting proper cable movement directly to the seal point increases the chance of leakage developing. A proper liquid-cooled cable gland will provide a positive grip suitable to secure a liquid-cooled cable, while enabling sufficient strain relief on the cable not to damage the cable's insulation.
Material Selection: Brass, Stainless Steel, or Nylon?
🛠️The selection of the proper material affects all aspects of sealing integrity, removal of corrosion, cost, and service life. There is no one perfect material to use in any situation; selecting the correct material depends on the environment where the product will be used, performance needs in the end product, and cost associated with using that material.
Brass Liquid Cooling Cable Glands
Nickel Plated Brass is a very popular material due to its excellent mechanical performance, corrosion resistance, and good cost performance. When it comes to industrial control cabinets, power modules, cooling plates and other types of enclosures, brass glands can be used in many different applications. An added benefit of using Nickel plated brass glands is that they have good stability of thread strength. Additionally, because of their unique properties, they are often easier than steel to machine to very close tolerances.
Stainless Steel Liquid Cooling Fittings
If you need materials that will withstand a tough environment, stainless steel is a great choice. It has very good corrosion resistance, strength, and durability, and thus can be used in applications such as outdoor systems, marine equipment, food-grade equipment, medical devices and high reliability data center infrastructure. Stainless steel liquid cooling fitting systems offer many advantages over standard brass or plastic fittings in terms of their ability to provide longer service lives.
Nylon Liquid Cooling Cable Glands
Glands made from Nylon (Nylon Glands) are lightweight, electrically insulating, and relatively inexpensive. In most applications, they will be utilized for devices subject to moderate mechanical loads and will not be installed in situations where corrosion may be an issue. Excellent quality nylon glands, along with the proper sealing method can meet IP68 ratings, however, they may not be suitable for use in high pressure or high-temperature liquid cooling systems.
Liquid Cooling Connector vs. Liquid Cooling Cable Gland
The definition of these two terms overlaps, but they are not exactly interchangeable. A liquid cooling connector is generally considered to be any component used to connect coolant hoses or tubing together. Many liquid cooling connectors will have included internal passages through which liquid travels directly through. A liquid cooling cable gland is primarily used for sealing and protecting cables when they enter into a device that has been cooled by liquid methods, such as through the use of a coolant gun.
Most modern systems contain both the connector and the cable gland; these elements provide support to each other. The connector manages the flow of coolant. The cable gland protects from water, dust, and mechanical stress to electrical connection sites. For example, in a rack-level liquid cooling system UQD quick-disconnect connector assemblies may be used for coolant supply and return, while IP68 cable glands will protect the power/signal wires attached to the server chassis or power distribution unit.
This information is useful to you as a buyer of either type of product. The tests performed on an item are relevant to its future performance. For example, a fluid connector should be tested for flow, pressure loss, and reliability of connection; while a cable gland should be tested for ingress protection, cable retention, seal compression, and environmental aging.
How UQD Quick Disconnect Connectors Relate to Liquid Cooling Systems
Due to their ability to rapidly connect and disconnect coolant lines while also greatly reducing the amount of coolant lost during this process, UQD quick disconnect connectors have generated much discussion amongst users of liquid cooling systems. In particular, UQD connectors are an important feature for use in data centers and for high-performance computing installations where it may be necessary to service a server, cold plate or rack manifold without having to completely drain the associated cooling loop.
Typically, UQD quick disconnects will have sealing mechanisms inside the connector to automatically close when unhooked to minimize spills, protect the system, and reduce time spent on maintenance activities. Depending on the configuration of your system, compliance with either OCP or UQD compatible specifications may be necessary for proper integration of racks/cold plates/manifolds, as well as between cooling distribution units (CUDs).
Even if it’s possible for UQD connecters, cables, and cable glands to perform separate functions, it makes sense to look at them together during system design, because if you have a good coolant connector but have an unreliable cable gland seal, you will still run the risk of a leakage/infiltration within your system. Therefore, a proper and complete thermal management design will include both a reliable fluid connection as well as a dependable means for sealing the entry of cables or wires into the enclosure.
Where Are IP68 Liquid Cooling Cable Glands Used?
Liquid cooling cable glands rated at IP68 are applied to electrical cables passed between sealed enclosures of electrical equipment to protect them from liquid leaking in or out of those enclosures. They are typically found in applications where very high currents, voltages or very sensitive electronic components are located adjacently to any coolant fluid piping.
Some examples are artificial intelligence (AI) server farms; high-performance computing rack systems; energy storage cabinets; electric vehicle charging stations; power conversion systems; industrial lasers; medical imaging equipment; semiconductor manufacturing equipment; telecommunication base station equipment; battery thermal management equipment; and outdoor electronics. In each of these examples, sealing components reliably ensures that the performance of the equipment and safety of the technician working with the equipment will not be compromised by moisture or dust contamination in the environment.
With the increasing density and compactness of modern electronic equipment, the gap between an electronic device and its cooling system continues to decrease. Therefore, ensuring that you have adequate protection against cable entry has never been more critical. Thermal management cable strainers must be able to keep their sealing capabilities in situations where vibration, changes in temperature, and coolant service operations occur.
How to Choose the Right Liquid Cooling Cable Gland
When selecting one of many products for any application, the first step is to gain an understanding of the actual operating conditions. Instead of choosing based solely on the thread size of appearance; engineers must first fall back on the complete list of MECHANICAL, ELECTRICAL, CHEMICAL, and ENVIRONMENTAL requirements.
Factors that determine suitability are: diameter of cable outside diameter; type of thread; thickness of panel; type of coolant; operating pressure; temperature range; compatibility of materials; level of vibration exposure; installation space; certification requirements. For example, for a compact server application, you might look for a small gland providing accurate strain relief; on the other hand for an outdoor cabinet storing energy/utility equipment, you would need a stainless steel invert solar; corrosion resistance over time.
After the installation has occurred, it is also essential to verify if the Gland supports the needed IP68 conditions along with the actual cable. Some items will qualify for IP68 only through very specific ranges of the cable diameter. Also, if the cable jacket is made from soft material, has issues such as an irregular shape, is braided together and does not fit any standard measurements, you may need to obtain custom seals for the inserts.
When it’s necessary to use custom liquid cooling connectors and cable glands for OEM or ODM projects, many elements can be taken into consideration such as; specific cable sizes, thread forms, sealing material requirements, mounting structure styles, branding necessities, and compatibility with OCP or UQD system architecture. In cases where off-the-shelf products cannot deliver expected performance based on factors like pressure or available space, using customized products can be an appropriate solution.
Installation Best Practices to Achieve IP68 Sealing
Even the best glands can fail if they are installed incorrectly. The performance of the gland at IP68 level relies significantly on proper assembly. Prior to installing a gland it is important to make sure that the cable jacket is clean and round (no deep scratches) and the panel surface on which the gland is being mounted is flat and smooth so that the O-ring can properly seal. If the surface on which the gland is being mounted is rough, painted unevenly or has any deformities, you could have leakages present on the mounting hole area.
Another important factor to consider is torque control. Gaps in the sealing path may develop if a component is not sufficiently tightened. Damage to the threads of a connector, crushed sealing insert, or deformation of cable jackets will occur if a component is too tightly fastened. Whenever possible, manufacturers should provide recommendations regarding proper tightening torques, especially in critical applications.
After installation it is recommended to perform a pressure/immersion test on any high value system to evaluate the system overall integrity. Engineers may perform these tests as well as a coolant compatibility test and thermal cycling test on liquid cooling equipment to help ensure that the sealant material will remain unchanged (not swollen, hardened, cracked or loss of compression) over the long-term period of time that it is in operation.
Common Reasons Liquid Cooling Cable Glands Fail
The majority of product failures occur due to an incorrect application of a product. For instance: a gland intended for general purpose waterproof connections may not be capable of withstanding use in a liquid cooled system near pumps; additionally, the incorrect cable diameters (gland sealing range does not correspond to cable) will mean that you do not have an IP68 rating protection in place.
Incompatibility of materials is one of the most frequent reasons for leaks. Certain coolants or additives may chemically attack rubber seals and/or plastic parts. If that happens long enough, the rubber may swell, crack, lose its elasticity and/or have a reduced sealing force. Therefore, compatibility of the coolants should be established in the early design phase.
Mechanical stress may produce incremental risk, for example: cable bending at the gland, vibration, inadequate strain relief, and/or repeated maintenance can all cause weakening of the seal. Therefore, when designing cable routes for high-reliability applications (where the cable gland is not meant to be the sole point of mechanical load support), you should have a plan in place to ensure that stress is minimized.
Testing and Certification: What Should Buyers Look For?
Buyers who are purchasing IP68 liquid cooling cable glands should not rely on product descriptions but instead request clear test documentation. Some examples of useful test documentation include the following: IP68 test reports, material data sheets, compliance with RoHS and REACH, UL material ratings, salt spray test results, temperature test data and information about compatibility with coolants.
Some requirements will vary depending on the intended use of the product and the market where it’s sold. For instance, industrial machinery might need to meet CE standards for electrical equipment; electrical components might need to be UL listed; outdoor equipment might require ultraviolet (UV) protection and salt fog test results. When it comes to liquid cooling solutions for data centres, most will need to conform with established industry specifications like (Open), Cloud, and/or UQD (Universal Data Centre) product specifications.
A supplier who has positive engineering expertise should also have the ability to demonstrate what certification(s) they have achieved with their products as well as the details regarding the testing and conditions experienced by that product. This is very important to mean E-E-A-T in technical purchasing: actual experienced customer, able to support with validated data, applied knowledge regarding specific applications, and full disclosure/understanding of how a product meets the appropriate levels of quality assurance.
OEM/ODM Customization for Liquid Cooling
Many projects can be served with standard products; however, liquid cooling designs usually require some level of custom-engineering support to ensure that they work properly. Using OEM and ODM support will help provide optimized sealing reliability, assembly efficiency, space utilization and long-term performance. Custom options can consist of thread type, body material, sealing ring material, cable length range, colour, surface treatment, logo identification, packaging, or special structural design.
Complex systems can also require customized solutions that are integrated with manifolds, cold plates, power modules, CDU units and/or rack-level liquid cooling architecture. If the system must meet UQD or OCP related requirements, early communication between connector suppliers and equipment manufacturers may result in the minimization of redesign costs and the reduction of development time.
A qualified supplier can assist you in a variety of ways, from reviewing your drawings and suggesting appropriate materials to providing samples and supporting tests. Furthermore, they can help modify the design based on customer feedback following installation. This assistance is particularly important in applications with high power densities, where adequate thermal performance, avoidance of liquid leaks, and ease of maintenance need careful balancing.
Buying Checklist for IP68 Liquid Cooling Cable Glands
- Confirm the exact IP68 test condition, including water depth, pressure, and duration.
- Match the gland sealing range to the real cable outer diameter.
- Check compatibility with the coolant, including glycol mixtures and additives.
- Select brass, stainless steel, or nylon based on corrosion, strength, and weight requirements.
- Verify the operating temperature range and thermal cycling performance.
- Review thread type, panel thickness, O-ring design, and installation torque.
- Ask for test reports, compliance documents, and material data sheets.
- Consider OEM/ODM customization for special cable sizes or system architecture.
FAQ: Liquid Cooling Cable Glands and Connectors
The two most common types of connectors include hose barb connectors and threaded fittings, but there are also compression fittings, blind-mate connectors, quick disconnect connectors, manifold connectors, and cable glands (used to provide a sealed entry for cables) found in electronic cooling systems. These can be chosen based on flow rate, pressure rating, size, serviceability and compatibility with the coolant used. Cable glands are used for places that the cable enters into sealed equipment, while fluid connectors carry the coolant throughout the cooling loop.
The quick-disconnect liquid cooling connector has an internal valve or shut-off function that opens to allow for the connector halves to be installed together (mated) and then again to allow for disconnecting (separating) the two connectors. This internal function provides the ability of the maintenance team to connect/disconnect the cooling lines with little to no coolant loss from the system. The UQD connector will be very beneficial in most data center and high-performance computing (HPC) situations because they require quick service, very low amounts of leakage, and repeated reliability of these quick-disconnect connectors.
In any case, if you look up "liquid cooling cable gland" you'll find many products that can be used near open systems such as cooling or liquid-cooled applications (like: A.I. Data Centres, EV chargers, Battery Energy Storage systems, Industrial Lasers, Medical Devices, Telecommunications Equipment, and Outdoor Control Cabinets) to create a connection point between two sealed enclosures, keeping the IP68 seal intact while preventing cable damage due to vibration or mechanical forces acting upon the cable through its termination point.
Select connectors and/or cable glands that correspond to the correct cable size, type of coolant, pressure range, and temperature. Use the correct sealing materials, apply the recommended amount of installation torque, ensure clean sealing surfaces, as well as minimize bending of cables at or near the connector or cable gland. For critical applications, perform pressure tests, immersion tests, coolant compatibility tests, as well as thermal cycles validation on the entire system prior to commencing mass production.
As an example, some commonly requested certification and compliance documents could be: IP68 run tests, IEC 60529 ingress protection tests, RoHS certification, REACH certification, UL material ratings, flame retardant material data sheets, CE related documents and salt spray test results for metallic parts. Additionally, when doing business with customers in a niche industry, they may also request coolant compatibility reports, temperature aging test results and any documents confirming compatibility with OCP or UQD systems.
Final Thoughts
When designed, tested, selected, and installed correctly for the application, liquid cooling cable glands can achieve IP68 water tightness. Choosing the best solutions involves high-quality sealing materials, precise machining, suitable body materials (e.g., brass, stainless steel, or nylon), and reliable strain relief. A well-designed liquid cooling connector strategy for high-density power systems involves more than just an efficient means of moving coolant; it is also necessary to prevent leakage, protect electronics from water damage, and ensure the reliability of the entire system over time. If your project requires custom cable lengths, rugged environments, or OCP or UQD compliant liquid cooling systems, working with an OEM/ODM manufacturer that has extensive experience will help you create a solution that meets your targets for performance and reliability, while accelerating your ability to integrate, and providing you with added long-term value.