At first, the answer seems simple: a cable that retains its full functionality even under water for a long time. However, such extreme applications are rare. Very often, cables are actually laid in a dry spot, but sometimes get wet, for example because a coolant leaks into a machine or because plants in the food industry have to be regularly injected with hot steam. Water-resistant cables are therefore required wherever cables can become damp. Water-resistant means that the plastic on the sheath does not dissolve over time. Some plastics naturally have this property, but not all of them do. When water cannot penetrate the plastic and get to the cores, this is known as a laterally waterproof cable. Cables that are particularly resistant to water for outdoor installation are also longitudinally watertight. If water penetrates at the connector on the end of the cable, it cannot spread along the cores, as a jelly-like filling made of water-repellent petroleum jelly prevents this
A water-resistant cable alone isn’t adequate, however. The critical point of a cable is where it is interrupted: at the connector. Under no circumstances must water penetrate between the plug and socket and wet the contacts, otherwise it could result in a dangerous short circuit. The transition, where the cable runs into the connector, must also be impermeable. In businesses in the food industry, where control cabinets are also cleaned with chemicals and steam, the openings in the control cabinets must also be sealed with cable glands
The IP protection class has been established to assess how dense an object is. “IP” stands for “International Protection”. The protection class is indicated by two numbers. The first number indicates whether foreign bodies can penetrate. “6” means “dust-tight” and is the highest protection class for foreign bodies. The second digit indicates how waterproof a housing is. Here, the protection classes range from “1” (protection against drops of water) to “8” (protection against permanent submersion) and even “9” (protection against water when cleaning with high pressure/steam jets). The highest protection class is IP69K, whereby “K” requires special protection in vehicles.