The Fire Regulations Hiding in Your Ceiling Void
The Short Run: Since January 2019, BS 7671 has required wiring throughout a building to be supported so it won’t collapse early in a fire, so plastic ties and clips can’t be the only thing holding cables up. Data cable also has to meet a minimum fire rating under BS 6701. If your ceiling voids are full of cable on plastic ties, or old cable nobody uses, get it checked.
Lift a ceiling tile in most offices and you’ll find the same thing. Bundles of data cable held together with plastic ties, lying across the tops of the tiles or strapped to the nearest pipe.
It looks harmless. In a fire, it isn’t. And for any work done since 2019, it doesn’t meet the wiring regulations either.
This one matters for facility managers because cable in a ceiling void is out of sight. Every contractor who passes through adds a bit more, and it rarely gets checked until something goes wrong. Here’s what the regulations say, why they changed and what to look for in your own building.
Why cable supports became a fire safety issue
When a fire takes hold, plastic cable ties and clips soften and fail long before the cables burn through. The cables drop, often across corridors and doorways at head height. Firefighters in breathing apparatus, working blind in thick smoke, can get caught in them.
That isn’t a theory. In April 2010, firefighters Alan Bannon and James Shears died at Shirley Towers in Southampton after becoming trapped by fallen cables. At the inquest, the coroner recommended that all cables, not just fire alarm cables, should be held up with fire-resistant supports.
What the regulations say now
The first change came in 2015. Amendment 3 to BS 7671 required cables in escape routes to be supported so they wouldn’t collapse prematurely in a fire. The 18th Edition went further. From 1 January 2019, regulation 521.10.202 applies to wiring throughout the installation, not only in escape routes.
In practice, plastic clips, ties and trunking can’t be the only thing holding cables up. The weight has to be carried by metal fixings, metal containment or another support that holds in a fire. Plastic ties are still fine for keeping a bundle neat on a metal tray, because the tray is doing the supporting.
Older installations aren’t automatically unlawful. But new work and alterations should meet the current regulations, and a fire risk assessor may well flag loose or badly supported cable as a hazard. If you’re the responsible person under the Regulatory Reform (Fire Safety) Order 2005, it’s part of keeping your fire risk assessment accurate.
Does it apply to data cables?
This is where it gets murky. BS 7671 is written for electrical installations, and people still argue about how far it reaches into data cabling. The Fire Industry Association points out that BS 6701, the standard for telecoms cabling, works alongside BS 7671 rather than replacing it.
Our view is simpler. A Cat6 cable hanging across a corridor traps a firefighter just as easily as a power cable, and the coroner’s recommendation covered all cables. So we support data cabling to the same standard, and you should expect any installer to do the same.
The other rule is what the cable is made of
Since July 2017, cables permanently installed in buildings have fallen under the Construction Products Regulation (CPR). It grades how a cable reacts to fire with a Euroclass rating, from Aca at the top down to Fca.
BS 6701 was amended in 2017 to set a minimum of Euroclass Cca-s1b,d2,a2 for data cable inside buildings, covering new installations, refurbishments and extensions. Cheaper cable is often only Eca rated, which falls short of that. The class is printed on the cable sheath, so it’s easy to check.
Older installations often used PVC-sheathed cable, which gives off thick smoke and corrosive gases when it burns. Most modern data cable uses low smoke zero halogen (LSZH) sheathing instead, which is far kinder to anyone trying to get out of the building.
Fire stopping is the hole nobody filled
Every time a cable passes through a fire-rated wall or floor, the hole has to be sealed again with a tested fire-stopping product. Otherwise fire and smoke can travel through the gap and bypass the compartments the building was designed around.
It’s one of the most common faults we find. A contractor drills through a compartment wall for one extra cable and leaves the hole open, or fills it with ordinary expanding foam. Whoever makes the hole should seal it, and it’s worth asking for photos of the fire stopping before the ceiling goes back.
What good looks like
In a well-kept ceiling void, data cable runs on metal tray, basket or J-hooks fixed to the building structure. It never lies on the ceiling tiles or hangs off pipework, ductwork or the wires that hold the ceiling grid up. Where cable runs in plastic trunking, metal clips hold it in place.
The cable itself is marked Cca or better. Every hole through a fire-rated wall is sealed and recorded. And redundant cable is taken out rather than left to add fuel and smoke. That’s how we install structured cabling, and it’s what you should see in the photos and records from any installer you use.
How to check your own building
If your building went up before 2000, check the asbestos register before anyone lifts a tile. Assuming it’s clear, you don’t need to be an engineer to spot the warning signs.
Lift a few tiles near the comms room and along the main corridors. Look for cable lying on the tiles, cable strapped to pipes or ceiling hanger wires with plastic ties, and plastic trunking with no metal clips. Check for open holes around cables where they pass through walls, and bundles of cable that clearly don’t go anywhere.
If you find them, the fix is usually straightforward. Re-support the live cabling on proper containment, strip out what’s dead and reinstate the fire stopping. We often combine it with a cabinet tidy and audit under our network maintenance work. Where power cables share the void, it can sit alongside electrical installation work too.
The bits that trip people up
❌ Plastic ties doing all the work
Plastic ties are fine for tidying a bundle on a metal tray. They’re not fine as the only thing between a cable run and the floor.
❌ Using the ceiling as a cable tray
Cable laid on tiles or tied to hanger wires adds load the ceiling wasn’t designed for, and it comes straight down in a fire.
❌ Leaving dead cable in place
Redundant cable adds fuel and smoke, and it’s usually the worst-supported cable in the void because nobody’s looked after it for years.
❌ Forgetting the fire stopping on small jobs
One extra cable for a new printer can mean one unsealed hole in a compartment wall. Small jobs need the same sign-off as big ones.
Not sure what’s above your ceiling? Book a free site survey.
Maybe nobody’s looked in your ceiling voids for a while, or you’ve inherited a building with years of cabling history. The place to start is a site survey. Not a guess. An actual survey, on site, that shows how your cabling is supported, what’s live and what needs to come out.
Viking Communications installs and puts right data cabling and electrical installations for businesses across Greater Manchester and the UK. Our team is City & Guilds qualified, ECS and CNCI® certified, and UKATA asbestos aware for work in older buildings. New structured cabling comes with a 25-year manufacturer warranty, and site surveys are free, with no hidden charges in the quote.
📞 0161 660 3002
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