New safety critical cabling report

Building safety systems depend on their electricity supply. Specifying cabling that is resilient if a fire breaks out is essential. It must be properly maintained to keep people safe if an emergency evacuation is needed. If a critical system fails extra damage to property is likely and more people are at risk. 

 

Generally, installers have a choice of polymeric (plastic) cables and mineral-insulated copper clad (MICC) cables. Using existing testing practices both cable types are classed as fire-resistant. 

 

Polymeric cables use mica tape and polymers which increase their resistance to fire but they can burn at 80°C. Additional halogens can increase fire resistance but release toxic halides if exposed to fire. There’s evidence that MICC cables perform to higher safety standards in ‘real fire’ situations. Despite this, there’s no requirement to use MICC cables for safety-critical uses. 

 

As yet cabling regulations haven’t changed to reflect their importance in fire safety. There’s a call for better understanding of: 

 

Questions about the effectiveness of cable testing and certification are long-standing. The Building Safety Act is now in force with new regulations for the construction industry and electrical safety systems. It applies to buildings at least 18metres or seven storeys high with at least two domestic properties. 

 

The Act updates guidelines for construction and management of higher risk buildings. It covers the whole supply chain including electrical safety systems and cabling. The current British Standard Code of Practice (BS8519) identifies six categories of power and control cables with survival times of 30, 60 or 120 minutes.