It's in the walls?!

A subject close to my tech brain and tech heart. Structured cabling, copper and fibre. Those thin copper cores and delicate fibre strands carry business’s operations day in day out, month after month, year after year without a second thought. They never get the recognition they truly deserve.

With multigigabit now well over the horizon, and many big vendors offering 1, 2.5, 5, and 10Gbps Ethernet capable switches. Structured cabling is going to play a pivotal role in utilising this extra bandwidth for access point backhaul, low latency applications and speeding up everyday operations.

This blog is my attempt to change the way we think about the data motorways hidden in walls, above ceilings or under our feet and why we should show some TLC to these motorways. After all, no one likes a pothole. I’m sure my cabling contractors will appreciate this one!

Lots of copper options

Structured cabling can be a myriad of letter combinations and numbers and can be just as acronym heavy as the rest of IT. How it’s broken down is category first then shielding, sometimes it can also be followed by an indication of the protective coating so it might look something like CAT6a U/FTP LSZH.
To me, other IT engineers and data cablers this will make sense but to others it’s a jumble of letters and I might as well be speaking Greek. So I am going to split it up and make it digestible.

What Category?

When we talk about copper structured cabling in 2025 we are looking at implementing either CAT5e, CAT6 and CAT6A. Why no CAT7 I hear you ask? I’ll leave this down to my very good friend Josh McAllister MD at Comfinity. This guy has forgotten more about cabling than I will ever learn. You can read why we skip CAT7 in his blog here The rise and fall of CAT7.

So when do you choose which category or CAT, as it is commonly known? I find this straightforward to answer and recommend to clients, though others can struggle. My guidelines are simple and are based off of occupancy for commercial spaces:

• Less than one year occupancy - CAT5e.

• More than two years but less than ten - CAT6.

• More than ten years - CAT6a.

Obviously, this isn’t set in stone, but for seventy five percent of installs, it helps to select the most cost effective solution. Of course, there are other factors to consider, and this is where speaking to the site is more important than anything else. It’s what ultimately decides the CAT of cable to be used.

A typical life cycle for a structured cabling installation is usually between twenty and thirty years in the office, warehouse and commercial environments. For more industrial and hazardous environments this is reduced and greatly dependent on the environment itself.

Shielding

Understanding the shielding section on a cable is a fun topic, as there are a lot of acronyms thrown around. Luckily for us, ISO/IEC has standardised the naming conventions under ISO/IEC 11801. To make it easier, I’ll break it down letter by letter and we will use F/UTP which you’ll often see on CAT6a cable.

F/UTP

U = Unshielded F = Foil Shielding S = Braid Shielding TP = Twisted Pairs

This might seem a bit dry or even irrelevant to start with, but I have worked across a number of sectors in my career and had to implement the correct shielding for the environment. For example, if I have no other choice but to run my data cables next to a large electrical cable, I would use F/FTP or better shielding to reduce any interference.

In a normal office environment with three compartment trunking, I can use U/UTP as there is going to be little to no interference. I have even seen SWA (steel wire armoured) cable used for environmental protection, I can say that’s probably the most difficult shielding to work with but if you need to drive a tank over it you don’t have much choice.

Fire Rating

Fire rating on data cabling is another intricacy to be navigated. It’s highly application and environment specific. It took me a little while to fully understand what’s needed and where. If you are unsure ask an expert, they will be able to advise you.

For the majority of commercial environments, I nearly always use Dca fire-rated cabling, as it aligns with most fire regulations in the UK (but always check your local regulations). In areas where the public is going to be present like stadiums or public buildings I will specify B2ca rated cable. This is critical, as in the event of a fire, the cable will minimise its contribution to the fire spreading.

I would strongly recommend to never install anything lower than Dca in indoor environments. I would also strongly recommend using LSZH (low smoke zero halogen) data cable, as it produces minimal smoke and harmful fumes for indoor areas aiding with evacuation.

This blog focuses on indoor areas. Outdoor cable runs have their own set of other best practices, rules and regulations, which I might do another blog on.

What about fibre?

Fibre or Fibre optic is another interesting topic. After all, it’s just light, right? Well, yes but what kind of light? Fibre optic can be split into two groups multimode and singlemode and you’ll be over the moon to know there are more acronyms!

Both types use light to transmit data down a tiny fibre optic strand, but in my experience, they have very different use cases. Just like copper CAT cables, multimode and single mode are backwards compatible within their own groups, but they are not compatible with each other.

Not shielding again!

So I can’t skip on shielding on fibre sadly, as it is very different from copper. With fibre, we talk about armoured and non-armoured options, plus loose tube and tight buffered types.

Armoured and non-armoured are fairly self-explanatory, just like in copper shielding section. Armoured fibre has an extra layer of protection, making it suitable for environments where the cable may get knocked or if you have any unwanted four-legged visitors.

But Loose tube and tight buffered have their own use cases:

Loose tube fibre is designed with the cores suspended in a gel or dry water blocking compound, making it ideal for ducting, outdoor deployments, or harsh environments to stop ingress so when linking buildings together through ducting loose tube is usually my go to.

Tight buffered does not have the cores suspended in the gel; instead, each fibre is surrounded by a protective coating. This design makes it ideal for indoor installations, like running between floors in a high-rise building via a riser. Tight buffered is easier to terminate and often looks similar to a standard copper Ethernet cable, which makes it easier to work with in office environments.

It’s important to note that some projects may require a hybrid deployment using both types to suit the environment they are being deployed in.

The last thing I will touch on with fibre shielding: if it’s going in ducting, it’s not always alone. Sometimes there are visitors that like to nibble and cause a massive headache on a Friday afternoon, because it’s always a Friday. Rodent-proof fibre exists, and I nearly always pay the extra to protect against the risk.

Multimode OM1, OM2, OM3, OM4 and OM5

Multimode is commonly used internally within a business, linking an MDF to an IDF or for specific use case scenarios where copper won’t cut it. If the distance is above ninety meters and below five hundred meters, I’ll always recommend a multimode fibre run. And because it uses light, it doesn’t suffer from EMI like copper does.

Lastly, it’s fast, really fast (only as fast as the multimode grade and transceiver). It easily outpaces the speeds on copper, with OM5 capable of supporting speeds of 400Gbps. Putting CAT6a in the slow lane at 10Gbps. This lends itself to high bandwidth applications and environments.

All my deployments of multimode fibre have been internal for customers either adding new fibre installs (greenfield) for the first time, or expanding an existing fibre deployment (brownfield). Since multimode is backwards compatible, it means no interoperability issues with older deployments but it is worth noting that it will only run as fast as the lowest multimode standard in the chain.

Currently with multimode the most popular connector by far is LC but there are a plethora out there I have used because it was a brownfield deployment, but they do have their use cases and purposes but I’m not going to go over them in this blog.

Singlemode OS1 and OS2

Singlemode is a different beast altogether, from the core size to the way the light is generated and the applications it supports. It’s heavily utilised within carrier networks (ISPs) supporting far greater distances and speeds. But it definitely has its place in data centres, and specific use cases.

With singlemode fibre, you can achieve speeds of up to 1Gbps over distances approaching 100km, and up to 400Gbps over distances of around 40km, although these figures depend heavily on the transceivers used. It’s easy to see why singlemode is the go to for carriers covering distances between street cabinets, exchanges, points of presence and data centres.

In data centres, singlemode is often used for uplinks between top of rack switches, where high-capacity bandwidth is needed, and for connecting core and aggregation layers.

I have been limited with the amount of single mode deployments I’ve personally rolled out. The ones I have done were either for satellite aerial deployments or for situations where we needed to relocate equipment, but the customer has a fixed circuit that cannot be moved. In these cases, I’ll leave the fibre tray in its original location (to keep Mr Carrier happy) and used an OS2 fibre run to extend the connection to the new equipment location.

Once again with connectors I see a clear divide. Internal uplinks or internal singlemode fibre runs use LC whereas the fibre coming to the customer’s premises is normally presented in an SC connector but there are other connectors to use these are by far the most common.

Have you tested it?

For me, whether it’s a brownfield or greenfield installation, I always make sure the cables are tested with a minimum of level III testing or validation testing (TIA/EIA-568 standards). My preference is IV or certification testing, which is defined in ISO/IEC 61935-1. This might seem overkill, but it ensures that every cable is tested to its full potential and with the highest accuracy. Nothing is missed, giving you complete peace of mind when it comes to start patching everything will work perfectly.

Some big players in this field are Fluke and Netally, though other vendors are out there too.

Lastly, something with the testing comes documentation. This is critical and sometimes forgotten. I’m sure the cabling contractors I work with roll their eyes at my documentation methods and how detailed I am. I cover outlets, patch panels, horizontal cables, backbone cables, and fibre trays.

There is no law on labelling cables, but some good standards are BS EN 50174 and TIA-606-B/C are good to work to, especially in high density environments. That said, even a cab letter and number E/233 is just as helpful. This would tell you it is in cabinet E and patch point number 233.

Labelling horizontal cables and backbone cables is something else I would recommend. When you’ve got a loom of 24 cables together, having clear labels makes it easy to identify where each one goes. Backbone cable labelling is useful at intervals, making the cable easily identifiable amongst other cables and services; no one is going to cut through your important backbone cable, although there should be another backbone via a divergent route if it’s possible.

Lastly, photos and maps. Take photos lots of photos, of how the cables are presented to site, the outlets themselves, patch panels, fibre trays, cabinets and any maintenance holes. Outlet maps and route maps are invaluable when it comes to locating outlets and tracking the routes cables take to that outlet. This will help with fault finding later down the line, potentially saving you hours trying to locate a broken cable. And if it’s coming up for a refresh, it can speed up the quoting process as the surveyor will be able to see what containment is being used and the existing routes and if they are accessible or not.

It's always worked…

The biggest struggle I have as an engineer who also deals with pre-sales is structured cabling. It’s by far the hardest sell and justification, mainly because overall it is misunderstood. Future proofing structured cabling is tricky, because we never really know what is around the corner — we have a good idea but can’t be certain. It goes back to the occupancy and use case.

In most commercial spaces, to future proof I’d recommend CAT6a. If it is a small office with cable runs shorter than fifty-five meters, we can achieve the same speed out of CAT6 10Gbps.

If we are talking high bandwidth or low latency environments like financial trading floors or labs, I would be looking towards CAT8 or multimode over short runs or singlemode over longer distances. This ensures performance after multiple hardware life cycles or refreshes, meaning you grow into your network, just like you did at school when your parents bought your school jumper one size bigger.

Lastly, on future proofing I am going to talk cabinets and containment. If there is one thing to take away from this blog, it’s cabinet depth. Trust me, it’ll trip you up sooner than you think. I have come up across this multiple times recently where switches were too shallow for new switches (and no, I didn’t spec these ones!). For wall mounted cabinets, I will use 600mm deep; I wouldn’t even consider anything less unless space is a huge constraint. Any free standing cabinet I’d choose 1000mm deep it fits most servers and most switches and routers.

I like to leave two to four rack units free for growth, because that cabinet they said nothing else was ever going to go in? You guessed they will want to add a UPS and two more switches. And then it’s a brand new cabinet and probably a good amount of downtime while you swap it out.

Then there is containment. It comes in all sorts of varieties — all-round-banding, basket and tray work. Make sure it is big enough to allow for expansion without a major rework, as this can be costly. There are calculators online to help with this. I use Excel Networking’s calculator, and it’s not failed me yet.

Termination

In all honesty, I can’t stress enough the importance of considering and investing in the data motorways we use and take for granted. These cables are the veins and arteries of most business IT communications; they deserve the same respect and attention servers, computers, routers, switches and wireless access points get. Invest in structured cabling, it will pay you back tenfold over its life.

I’ve been privileged enough to take on the bulk of structured cabling where I work, and even more so to pick my contractors and build my network throughout the UK. This has given me the confidence to take on structured cabling jobs from Preston to Brighton and deliver them to the same high quality regardless of location or team.

Structured cabling is as much a trade as it is an art. Just like art, everyone can try it, but only a few can make a living from it, and even fewer can do it really well.

To the magicians I work with

I’ve been privileged to work with some amazing contractors across the UK who share my commitment to quality structured cabling. Making cables appear where it shouldn’t be possible to have a datapoint, never cutting corners, and always giving your all. A true testament to your skill and dedication. You guys are top notch, the crème de la crème, and I couldn’t dream of a better set of teams to work with me.