A fire at any of the five thousand plus telephone exchanges in the UK not only poses a risk to human life, but means potentially expensive telephone and internet disconnection for local companies and loss of business for the service provider. Meirion Buck, Senior Design and Technical Manager for Adaptaflex discusses the dangers of poor cable protection at telephone exchanges across the country.

The threat of fire is always present in environments where a large amount of cabling is in constant use, with telephone exchanges being at particular risk due to the heat of computer equipment being operated nearby and the fact that many cable management solutions in these facilities are outdated. 

Cable fires can start for a number of reasons, but an ever growing threat, especially in underground environments, comes from rodents. A chewed cable can easily impact the effectiveness of the wiring and, at worst, generate electrical short circuits and sparks that can ignite. Many telephone exchanges are located within enclosed environments that are also the natural habitat of mice and rats. The Manchester exchange for instance, is situated 115 feet underground, making the proximity of rodents unavoidable.

The impact of foreign bodies making contact with internal wiring could be another cause of electrical faults and fires, whilst water damage can cause loss of connection for landlines, as seen at the start of this year in Chester. 

With each major city having its own telephone exchange, ensuring complete protection is a large scale operation. Our Adaptaflex team is currently assisting on an established programme of upgrades at the exchanges of a major UK telecoms provider, with a number of quick and effective solutions are being installed over the next three to five years.

Using the specification and other criteria, we recommended a combination of non-metallic PRCS conduit and Adaptalok ATS fittings, specifically the blue elastomer version as it acheives the V0 fire rating.  paying attention to the particular enviornmental constraints of an exchange, the PRCS conduit was an ideal choice because of its suitability for use in confined areas, due to its Enhanced Low Fire Hazard (LFH), self-extinguishing, low smoke and zero halogen properties, as well as its good compression and tensile strength.

As access to these types of cables is often limited, in-situ checks are unlikely and monitoring of the strong threat of exposure to dirt and water could be limited. As a result, ingress protection is vital and remained a key consideration for the exchanges and the final solution.

For more information please contact: ABB Ltd