Cables in buildings

[lyledunn]

I am interested to know if anyone is aware of a fire incident where the fixed wire cabling contributed to the conditions being worse than they would have otherwise been. For example, did cables propagate the fire or produce emissions that caused issues?
There is rightly much concern in the electrical installation industry regarding the selection and erection of cables and wiring systems to mitigate perceived risks. We have already tackled the premature collapse of cables during firefighting operations and restricted the use of cabling and wiring systems in buildings with an elevated fire risk to those that meet certain propagation and emission criteria. BS7671 sets out the minimum requirements but I believe that the industry is going above and beyond, motivated, perhaps, by the increased focus on general fire safety. It would obviously be prudent if things were done on solid evidence.

[Crusher]

i'm not aware of any, other than old VIR cable. Submitting FOIs to fire and rescue service might produce results, or even a few phone calls to their fire investigators might be worth a try.

[Fishy]

There was an incident on the London Underground many years ago where a tunnel became smoke-logged due to a cable fire.  There are certainly many locations that I've seen where cables are the predominant fire load (e.g. back-of-house corridors).

I will offer an opinion that those who write BS 7671 haven't covered themselves in glory, when it comes to fire-safety related content (e.g. metal fixings on cables over 'escape routes' - with no explanation what an 'escape route' is)!  In this case, there might be some underlying issues that makes changes necessary:

BS EN 50575 (Power, control and communication cables. Cables for general applications in construction works subject to reaction to fire requirements) is a'harmonised' EN (hEN) and in the UK compliance with is has been mandatory under the Construction Product Regulations since July 2017.  There is no equivalent to ?Low Smoke Zero Halogen? in this standard ? instead it refers to BS EN 13501-6 for the fire performance requirements.  Classifications are complex and are in the form ?Xca sNx dN aN?.  There are 7 main classes each with multiple variations to cover smoke, production of flaming droplets and the acidity of the combustion products.  Effectively, there are 100+ combinations of these four factors that could be specified.

Little guidance on what classifications should be used exists, except for data cables where Cca s1b d2 a2 is recommended (for fixed cables) in BS 6701.

So, you can now only supply cables complying with the hEN, and under that standard specifying 'low smoke, zero halogen' is meaningless (so far as I understand none of us should be using that terminology any more).  They're probably therefore trying to get their heads around what that all means, and to issue some guidance to designers / installers as to what Euroclass cables to use, now they can't just recommend LS0H?