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Structured cabling products are expected to last for years in offices, but faced with the more extreme conditions common to industrial workplaces, laboratories, or hospitals, it's a very different story.

In harsh environments standard connectors run the risk of corrosion, wear, being clogged with debris and ultimate failure. For the user, this means high maintenance costs from troubleshooting and component replacement.

Current estimates predict that by 2004 more than 22% of new manufacturing equipment will have an Ethernet connection, allowing the factory floor to become a seamless extension of a firm's network. This technology is appropriate for a range of sectors including warehouses, mining and refineries, all of which have challenging environments, making trouble-free cabling vital.

Ensuring that cabling keeps pace with these advances is a situation the industry is actively addressing. Standards groups worldwide are working to define the requirements of cabling installed in industrial environments. These standards will include environmental performance specifications, known as the International Protection (IP) rating, for industrial connectors.

The IP rating system uses two digits to characterise the level of protection a sealed enclosure provides. The most stringent rating for data connections is IP67, indicating that a mated connector and plug is sealed against the ingress of dust and will withstand temporary immersion in water.

Products that will meet these stringent requirements are already coming on to the market. These are typically RJ45-style connectors and plugs fitted with bayonet-style outer housings. Key advantages of the bayonet interface include superior resistance to moisture and a positive quick-twist lock that reduces the mating time between the outlet and plug. In addition, the mating resists vibration by maintaining the plug's relative position to the outlet.

Avoiding problems
For the contractor, the priority is in understanding what conditions are likely to pose problems for the cabling and, therefore, where these specialised products should be used.

Essentially, difficulties are likely to be caused when standard cabling comes into contact with the following environments, usually at industrial, medical, marine or construction sites:

humidity and moisture – traditional cabling corrodes over time when exposed to even moderate humidity, this can lead to intermittent transmission problems. In severe cases, an outlet's contact pins can completely decompose. Also, the cabling cannot tolerate any submersion or liquid spray;

corrosive materials – exposure to corrosive gases and liquids is common in industrial situations. Oil, gas and chemicals can eat away at the outside connector housing, plug and jack metal contacts and cable jackets;

temperature extremes – most cabling systems are manufactured to tolerate temperatures from -10-60 °C, typical of most office and light industrial environments.

However, it is common in harsh environments for temperatures to spike outside or exceed this range for an extended period of time. The result is transmission failures and reliability issues;

vibration – when exposed to extreme vibration, the contacts in a plug wear against the pins in an outlet. Pins become pitted at the contact point, which degrades reliability and if they are exposed to moisture, corrosion results;

electromagnetic interference (emi) – where data cables are close to manufacturing equipment or electrical pathways, they may be subject to heavy emi as these generate electrical fields, which can cause noise to couple onto the data pathways and compromise the integrity of data signals. In such situations, the use of screened cables and components is common. Metallic foils around the cable conductors provide good immunity to high frequency interference. However, for screening to be effective, the foils must be fully bonded together and properly earthed, involving additional work and cost.

Providing solutions
An alternative solution is to avoid the use of metallic components and install a fibre optic system.

While fibre optic cables provide excellent emi immunity, their performance is severely degraded when connection points are contaminated by dust, grease and moisture. Installers must make sure that splicing, termination and patching of optical fibres is carried out in clean and environmentally controlled conditions. In dirty or damp locations, fibre optic connectors must be housed in enclosures fitted with appropriate glands and seals.

Frequently, the problems of dealing with a harsh environment may only refer to parts of a project site. For example, there may be a portion of an installation in areas prone to dust or temperature extremes or a need for connectivity in areas of high humidity such as wash rooms.

In the past, the solution has been to install traditional cabling systems and hope for the best; or custom-made protective enclosures – both of which are frustrating and costly for end-users.

In contrast, specialised IP-rated products can now provide protection against the entry of moisture from airborne humidity or direct contact with the liquid, reduce vibration and resist corrosion from chemicals.

With the cabling industry keeping pace with advances across the IT world, there should be no need for contractors to resort to keeping their fingers crossed when it comes to installing cabling in difficult areas.

The products are in the market, industrial standards are approaching fast and the outcome should be far less time-consuming maintenance and costly repair bills for the customer.