Cat6 vs Cat6A vs Fiber: Which Cable Run for Which Job

When a customer asks us to wire a new office, conference room, or building, the first question is always which cable. The answer matters because the cable goes in the walls and stays there for 15-25 years. Picking wrong on the day means renovating to replace it later.

This post walks the three options most West Texas businesses see: Cat6, Cat6A, and fiber. Plain English. No vendor preference. Where each one belongs.

Cat6 — the standard for desks and most rooms

Cat6 is the workhorse twisted-pair cable. It supports 1 Gbps to 100 meters and 10 Gbps to 55 meters under good conditions.

Use it for:

• Standard office desks and workstations
• Phones (PoE-powered VoIP handsets)
• Conference room displays and boardroom AV
• Most printers and copiers
• Wireless access points in normal office environments
• Camera runs under 100m where the camera itself is 1 Gbps

Don’t use it for:

• Server-to-server in a rack (use Cat6A or fiber)
• Outdoor runs without conduit (use outdoor-rated or fiber)
• Anywhere you might want 10 Gbps later than 5 years from now

Cat6 is the right answer for 80% of in-office runs. Cheaper than Cat6A by roughly 30% on cable cost. Faster to terminate. The connectors are smaller and easier to work with.

Cat6A — when 10 Gbps to the desk matters

Cat6A is a thicker, better-shielded version of Cat6 that supports a clean 10 Gbps to the full 100 meter run. The trade-offs: bigger cable diameter (so fewer fit in the same conduit), heavier, more expensive, harder to terminate cleanly.

Use it for:

• Server room patch panels and equipment racks
• Wireless access points where you expect Wi-Fi 6E or Wi-Fi 7 client speeds (some flagship APs now have 10 Gbps uplinks)
• High-end media production workstations
• Any run where the device on the end is 10 Gbps and you don’t want fiber for whatever reason

Don’t use it for:

• Routine desk drops where the workstation has a 1 Gbps NIC. Wasted money.
• Long runs over 100m. Use fiber instead.

The mistake we see: customers paying for Cat6A on every desk run because the contractor sold them on “future-proofing.” For a typical 25-person office where every workstation has a 1 Gbps NIC and the user runs Microsoft 365, the actual benefit is zero today and probably zero five years from now. Save the money for the runs that matter (server room, AP uplinks).

Fiber — for distance and isolation

Fiber optic cable carries light instead of electrical signal. It has three advantages over copper:

1. Distance. Single-mode fiber runs kilometers. Multi-mode runs hundreds of meters. Cat6/6A tops out at 100m.
2. No electrical interference. Useful in industrial environments, near big motors, near radio equipment, near medical imaging.
3. Building-to-building isolation. A copper run between two buildings can carry a lightning strike from one building to the other. Fiber doesn’t. This alone makes fiber the only correct choice for any inter-building run.

Use it for:

• Anything between buildings, even short distances
• Server-to-switch in racks where 25/40/100 Gbps is in play
• Long runs in larger facilities (manufacturing floors, warehouses)
• Long camera runs where the camera supports fiber-fed media converters

Don’t use it for:

• Routine office desk drops. Overkill, and your laptop has an RJ-45.
• Anywhere PoE is expected. Fiber doesn’t carry power. (Yes, there are hybrid composite cables. They’re niche.)

The trap with fiber is that the install requires specialized tools and skills. Bad terminations cause intermittent issues that look like everything else. Hire someone who does fiber regularly, not someone who saw a YouTube video.

The two costly mistakes most installs make

1. Mismatched terminations

A run is only as good as its weakest connector. We see plenty of Cat6 runs with Cat5e jacks at the wall, or Cat6A patch panels with Cat6 keystones. The link will appear to work, then will start dropping packets when it gets pushed.

The cure: spec the entire path the same way. If you’re running Cat6, every connector, panel, jack, and patch cord on that run needs to be Cat6. Same for Cat6A. The cable is the cheap part; the terminations are where corners get cut.

2. Skipping certification

Every run should be tested with a real cable certifier (Fluke or equivalent). Not a $30 continuity tester. A certifier verifies the link meets the actual TIA-568 spec for its category — return loss, near-end crosstalk, attenuation, propagation delay.

Untested runs work until they don’t. Working but uncertified means your cabling vendor cannot prove the cable is the cause when something breaks. Most certifiers will print a one-page report per cable. Demand them. We hand a binder to every customer at install completion.

What we install by default

For a typical small business office:

• Desks: Cat6, in-wall keystones, blue jackets
• WAPs: Cat6 to 1 Gbps APs, Cat6A to 10 Gbps APs (Wi-Fi 6E / 7 flagships)
• Cameras: Cat6 PoE+ to standard IP cameras
• Server room patch panels: Cat6A, all positions
• Server-to-switch in rack: SFP+ DAC or fiber
• Building-to-building: single-mode fiber, in conduit

Every run gets terminated, labeled at both ends, and certified. The customer gets a labeled rack diagram and a certification binder.

Who installs it

Cabling and physical security work at robb.tech is delivered through our sister company, West Texas Wi-Fi & Networking (TDPS Lic. #B31108601). Same office, same crew. Cabling is included for Carbon Managed customers; Steel and Titanium customers get the Steel-plan rate ($150/hr) on cabling project work; off-plan project rate is $200/hr.

If you’re planning a buildout, expansion, or new conference room, the free IT Blueprint Assessment covers a cabling walk as part of the broader audit.