Cable Assemblies Designed and Built for High Moisture and Humidity
When the environment that a cable assembly is to be installed in includes high moisture, high humidity, and the potential for the assembly to be immersed in water, the designer needs to be concerned with the assembly's ability to be able to provide years of use without pre-mature failure. To do this the designer must take into consideration the cable assembly or wire harnesses ability to not allow ingress of water, along with the capability to retard and prevent any fungal growth on the cable assembly.
Protection Against Water Ingress
Epec has the experience to design and build cable assemblies used in the most stringent environments. Our engineering team understands the requirements of these applications and has the understanding of the codes that are applicable in these applications.
When a designer considers the need for protection against water ingress, they will in most cases refer to the IP code (International Protection Marking, IEC standard 60529). The IP code classifies and rates the level of protection provided against intrusion of body parts, such as hands and fingers, dust, accidental contact, and water by electrical enclosures or connectors of any sort. The IP code is published by the International Electrotechnical Commission (IEC).
The purpose of the code is to provide users with more detailed information rather than vague terms such as "waterproof". Each digit in the code indicates conformity with the conditions the enclosure or connector was subjected to. If there is no data available to specify a protection rating to a criterion, the digit is replaced with an "X". If no protection is provided the digit "0" is used.
The most common codes used for a cable assembly are IP67 and IP 68. The third digit of the code specifies the level of protection against hazardous parts and the ingress of foreign objects such as dirt and dust. In both the IP67 and IP68 ratings, they would be dust tight. For this discussion we will only be considering the water ingress rating, or the fourth digit.
The fourth digit of the code specifies the level of protection against moisture/water ingress. For the IP67 the test parameters would be immersion of the component in water up to 1 meter in depth for a period of 30 minutes. A passing component would not allow any harmful quantity of water to ingress.
The IP68 code test parameters are more vague. It is understood that the IP68 test conditions are greater than the IP67 parameters but are specified by the manufacturer of the component. In most cases the depth is up to 3 meters and the duration is longer than 30 minutes. A passing component would not allow any harmful quantity of water to ingress.
Cable Assembly Fungal Growth Test
In some applications, such as life-saving appliances used aboard shipping vessels, there is a fungal growth condition that needs to be addressed in addition to the water tightness rating. The fungal growth test requires the designer of an assembly to choose components that inhibit mold/fungal growth both along and within all components. The test for fungal growth for life saving appliances is that the assembly gets sprayed with a suspension of mold spores and is then paced in a mold growth chamber. The chamber maintains a temperature of 29°C +/- 1°C with a relative humidity of not less than 95%. The assembly remains in the chamber for a period of 28 days and after the incubation period is inspected for mold/fungal growth. A passing assembly would display little or no mold growth.
Common Cable Applications Exposed to Water
- Life Jackets
- Safety Lights
- Fluid Control Machinery and Measurement
- Industrial Facilities
- Life Rafts
- Emergency Lighting
- Medical Diagnostic and Monitoring Equipment
- Water/Sewerage Treatment Facilities
Epec's Advantage in High Moisture/Humidity Cables
Starting with the basic cable design the Epec engineers associate the environment the assembly will be installed in with the requirements associated with the application. This understanding will guide the selection of components that best fit the needs and the requirements of the environment the assembly will be installed in. We keep all steps of production in-house.
Our vertically integrated approach allows our engineers to work with our production group to ensure there is an understanding companywide of the application each assembly will be installed in. This approach ensures that the end product meets our exacting standards and those of our customer.