Belden Essential Cable Facts: Temperature Fluctuation
Many building systems are subject to relatively large changes in temperature. Not just the ones regulating heating and air conditioning, but also lighting and other building management systems. Contrary to what some cable suppliers would have you believe, not every cable is up for that challenge.
Which cable components are critical?
When it comes to temperature fluctuations, key components are:
- Insulation is a dielectric that separates the cable conductors both physically and electrically. Its primary function is to protect the conductor and support the transfer of electric energy from point to point.
- The cable jacket is an outer covering. Its primary role is to protect the internal cable components from the external environment.
What is the threat of temperature fluctuation?
The types of insulation and jacketing materials used in a cable design will determine a cable’s maximum and minimum operating temperature. Unfortunately there are many cables on the market that have not been designed to accommodate their installation environment. The grades and types of cable insulation and cable jacketing materials used by cable manufacturers can vary enormously; subjecting a cable to temperatures for which it was not designed can present great risks.
What is the effect of temperature extremes on sub-standard cable?
- Degradation of cable insulation through temperature fluctuations will expose the cable conductor.
- If the cable’s jacket cannot withstand the temperature in the building system and fails, the inner cable components will be exposed.
- When exposed to temperatures higher than specified, insulation and jacket will melt; when subject to lower temperatures, they will become brittle and disintegrate.
What risks does this pose to a building or a system?
- System failure: breakdown of the cable's protective conductor insulation can lead to decreased signal transmission and even a complete system breakdown.
- Fire hazard: gradual erosion of the protective layers of cable insulation will eventually give way to the heated copper conductor and ultimately become a source of fire ignition.
- Major maintenance and repair costs: disintegrated insulation and jacket will lead to failure of the cable and eventually the complete system, requiring costly maintenance as a result of re-installation of the cabling.