In short
Often, yes. Every Wi-Fi access point gets its data and its power through one network cable, and a damaged or substandard run can cut its speed to a tenth or make it reboot under load. Signs include one area always being worse, access points dropping off, and poor speed close to the access point. Check the link speed on each switch port and swap the patch leads before buying new hardware.
Wi-Fi drops, video calls freeze and the card terminal times out mid-sale. The usual response is to blame the access points and buy new ones. Every access point is fed by a cable, though, and a bad cable makes good Wi-Fi hardware look broken.
Here's how to tell whether your Wi-Fi problem is in the wiring, what you can check in ten minutes, and what fixing it involves.
Every access point is only as good as the cable feeding it
An access point is the small disc or box on your ceiling that broadcasts Wi-Fi. It gets two things from one network cable: its connection to the rest of your network, and its electricity. Sending power over the data cable is called Power over Ethernet, or PoE, and it's why most access points have no plug of their own.
That single cable is a single point of failure. A gigabit connection uses all four pairs of wires inside it. If one pair is damaged, the link often drops quietly to 100 Mbps, a tenth of the speed, and keeps working. Nothing flashes red. Everyone on that access point shares the slower link, so the Wi-Fi feels sluggish even with full signal bars.
Power problems show up differently. An access point that isn't getting enough power can reboot under load, switch off some of its radios, or drop off the network for a minute at a time.
Five signs the fault is in the wiring
- One area is always worse. The same meeting room or the same end of the bar struggles, whatever hardware you put there.
- An access point drops off and comes back. Staff notice Wi-Fi vanishing for a minute, or your monitoring shows a device rebooting for no obvious reason.
- Speed is poor right beside the access point. A strong signal with weak speed points to the cable behind the access point rather than the radio.
- It started after building work. New partitions, a ceiling repair, an office move or a desk reshuffle are when cables get kinked, stapled or crushed.
- New access points changed nothing. If you replaced the hardware and the problem stayed, look at what the hardware is plugged into.
The cost shows up differently by sector. In a hotel or restaurant, a card terminal that drops mid-transaction costs you the sale and the guest's patience. In a warehouse, handheld scanners that lose connection stall picking and dispatch. In a creative studio, large files crawl when one access point is stuck at 100 Mbps.
What we find behind the ceiling tiles
When we look at a site with Wi-Fi complaints, the same handful of faults come up again and again.
- Old Cat5 runs from a fit-out fifteen or twenty years ago, never replaced.
- Hand-crimped connectors made up on site without testing, with pairs untwisted too far or in the wrong order.
- Cheap patch leads in the comms cupboard, often the oldest leads in the building.
- Copper-clad aluminium (CCA) cable sold as Cat6. It costs less, breaks more easily and runs hotter when it carries PoE.
- Runs longer than 100 metres. Standard Ethernet cabling is designed for a maximum of 100 metres per link, patch leads included. Past that, errors climb.
- Network cable sharing a tray with mains power cable, picking up interference along the way.
- A switch that can't power everything. Every PoE switch has a total power budget. Add a few access points, cameras and desk phones and you can exceed it, at which point the switch starts cutting power to some ports.
None of these is visible from the office floor, which is why they get missed.
Checks you can do in ten minutes
If your network has a management dashboard, such as UniFi, you or your IT provider can run these checks without lifting a tile.
- Read the link speed on each access point's switch port. Anything showing 100 Mbps where you expect 1 Gbps or more is a cable or connector fault until proved otherwise.
- Check PoE status and the switch's power budget. Look for ports reporting power faults, and for a switch running close to its total.
- Look for errors on the port. A climbing count of packet errors on one port points at the cable on that port.
- Swap the patch lead. Replace the short lead between the switch and the wall panel with a known good one. It costs a few euro and fixes more problems than you'd expect.
- Ask for the certification report. When cabling is installed properly, every run is tested and the results are handed over. If nobody can find that report, assume the cabling was never tested.
Our earlier post on seeing your whole network in one dashboard covers how this kind of monitoring catches a failing cable before your staff do.
Test, repair or recable
Testing the cable runs
The most basic test checks continuity and wiring: that every wire in a run is connected end to end, in the right order, with no breaks or shorts. That alone finds most crushed cables and badly made connectors. A full certification test goes further, using a handheld certifier to measure each run against its rated category, such as Cat6, and produce a pass or fail report. On a typical office of 20 to 40 network points, testing takes a day or less and causes little disruption.
Repairing individual runs
Often the fault sits in a few places: a bad connector, a crushed section above one ceiling, a failed port on the patch panel. Re-terminating or replacing those runs costs far less than recabling, and can usually be done outside opening hours.
Recabling
Recabling makes sense when most runs fail, when the cable is CCA or old Cat5, or when you're refitting anyway. It's a bigger job, and planning it well matters as much as the cable you choose. Our post on building a network with room to grow covers how to approach it as part of a fit-out.
Why newer access points raise the bar
Wi-Fi 6E and Wi-Fi 7 access points can move more data than a 1 Gbps link carries, and many draw more power than older PoE switches supply. Many models expect a faster uplink and a higher-power PoE port. Cat5e in good condition can carry some of those faster speeds, but marginal cabling won't. Before you upgrade access points, test the cable they'll sit on. Placement still matters too, and our post on Wi-Fi designed from a survey covers where access points should go.
Where to start
Start with the link speeds and the patch leads, because those take ten minutes and cost almost nothing. If any access point shows 100 Mbps, or the switch is near its power budget, you've likely found your problem.
If the checks point at the cabling itself, get the runs tested before you spend money on new access points. Testing tells you exactly which runs to repair, and a full certification report also gives you a baseline for any future upgrade.
We run these checks as part of our networking service, including continuity and wiring tests on the cable runs, and we'll tell you in plain English what we found and what it will cost to fix. If your Wi-Fi has been blamed for months and nothing has helped, get in touch and we'll look at the cable first.
Can a faulty network cable cause Wi-Fi to keep dropping?
Yes. An access point gets its network connection and, usually, its power through one cable. A damaged cable or loose connector can make the access point reboot, lose power under load, or drop its link speed. Users experience that as Wi-Fi dropping out or crawling, even though the access point itself is working. Checking the switch port for that access point usually shows the fault.
Is Cat5e cabling good enough for Wi-Fi 6 and Wi-Fi 7 access points?
Often, if it was installed properly and tests well. Cat5e handles 1 Gbps comfortably, and in good condition it can carry some of the faster speeds newer access points use. Old, damaged or untested Cat5e is less certain, and plain Cat5 is past its useful life. The safest answer comes from a certification test of your actual cable runs before you upgrade.
How can I tell if my office cabling was ever tested?
Ask whoever installed it, or your landlord or fit-out contractor, for the certification report. Proper installers test every run with a certifier and hand over a report listing each cable with a pass or fail result. If nobody has one, assume the cabling was never certified. Labelled wall ports and patch panels are a good sign, but they don't prove testing took place.
Do I need to recable the whole office to fix bad Wi-Fi?
Usually not. Faults are often limited to a few runs, a bad connector or a worn patch lead, and those can be repaired individually for far less than a full recable. Testing first tells you which runs have failed. Recabling makes sense when most runs fail, the cable is old Cat5 or copper-clad aluminium, or you're refitting the office anyway.
What is PoE, and why does it matter for Wi-Fi?
PoE stands for Power over Ethernet. It sends electricity down the same network cable that carries data, so access points, phones and cameras don't need a separate plug. It matters because every PoE switch has a limited power budget, and poor cabling makes power delivery less reliable. An access point short of power can reboot, switch off radios or vanish from the network.