Troubleshooting starts at Layer 1 – the Link Layer. So it’s important to get this right. You may say “it’s just cabling, how hard can it be?”. We’ll, read along. I’ve seen way too many people get it wrong and pay for an expert to re-do it, so I thought I’d touch upon this fundamental topic.
The goal here should be to get the cabling done right the first time around to avoid countless hours of troubleshooting cabling issues. The last thing you want is to climb up ladders in narrow spaces tracing cables and re-terminating jacks.
I’d rather spend the extra 10mins terminating a connector right, than coming back to it later and re-doing everything.
The 2 main types of data cables are Solid Core and Stranded.
(There are other categorizations like Cat5e, Cat6, Cat6a, Cat7/8. Their primary difference is in the number of twists per inch and how much data they can throughput.)
Solid Core
Each of the 8 cables inside the outer cover that for the 4 Paris is made up of solid copper wire. It’s usually either 24 gauge (AWG) or 23 AWG (thicker).
Stranded
Think of stranded cable as bundles of hair. Each of the 8 cables is a bundle of smooth hair like strands or copper. This makes the cable more flexible. It is primarily used for patch cabling where the cable needs to twist and turn more often. These are usually machine terminated. One should not form a habit of creating patch cables with stranded copper. Just buy them in bulk.
| Type | Flexibility | Use | Pros | Cons | Image |
|---|---|---|---|---|---|
| Solid Core (Copper) | Hard | Horizontal Cabling | Quality Signal | Higer price |  |
| Copper Clad Aluminum (CCA) | Brittle | Cheap Horizontal Cabling | Cheap | Poor signal quality, not for PoE |  |
| Stranded | Soft | Patch Cables / PC Cables | flexible | difficult to terminate |  |
| Shielded (STP) | medium | Audio/Video | Lowest interference | Expensive/Bulky |  |
Connector Types
Both these cables take different plugs. A lot of people mistakenly interchange plug types and consequently face connectivity issues.
Not all RJ45 connectors are the same. You must choose the right connector with the right type of cable depending on your application.
The table below summarized these well.
| Type | Use | pic |
|---|---|---|
| 2-Pronged | Stranded or Solid |  |
| 3-Pronged | Solid Core |  |
| 3-Pronged Piercing | Stranded only |  |
| with Tray | easier to prepare |  |
| Staggered | lowers cross talk |  |
| Shielded | lowers Near End Cross Talk (NEXT) |  |
You will also see Rj45 connectors advertised as “for solid and stranded cables“. I’ve used those on solid core cables with failure! You may have had positive results with those but I would avoid them. We’re not talking about 100’s of dollars of difference here. they’re all $10-20 per pack of 100 connectors!
Cable Thickness
The thicker the copper, the less the resistance, the better the current flow.
Thickness of the copper core is measured in AWG (American Wire Guage).
23 AWG is thicker than 24 AWG (for whatever odd reason 🤷🏻♂️).
Jacket Type
Plenum (LSZC)
LSZC (Low Smoke Zero Carbon) is a requirement for most building codes for cables running in heating ducts. This is deemed safer in case the building or cables catch fire and the outer jacket of your cables don’t produce as much toxic fumes.
PVC
These are cheaper in price and fine if you’re not running them in heating ducts.
Wiring Standards
Lastly, follow a cable standard to make everyone’s lives easier to troubleshoot. Stick to one (for straight-through cables), EIA/TIA T568A or B. Personally I always follow “B” for no particular reason. I’ve been told it’s more dominant in installations.
Click on the image for a large high resolution picture. Print it out when crimping cables or save the image on your phone like I do. It’ll get embedded in your head after 5 cables, hopefully.
Bottom line is: Get the right cables with the correct connectors to avoid issues.
Crimping and testing is a whole new topic. Hopefully I’ll cover that in another post.