CAT
As I’m having my flooring up soon, I’m thinking of laying some cat5/6 cables under the loop.
From the router to the loft, and router to lounge, both sound fine. Going from the Loft CCTV to TV; I'm guessing that's for monitoring the CCTV recorder, so this is in place of what would be an impractical length for HDMI, which means you'll be using a balun system to convert from- and back to- HDMI. If that's the case, the Ethernet cabling requirement for that will be set by the Balun system.
In my experience, you may need IR control back up to the recorder, so that would normally require two Ethernet cables. The safest option is to buy or research a suitable Balun system first, then install the recommended cabling. Failing that, two shielded CAT6 cables should cover you.
[[On a side note (and mainly for the benefit of any casual readers rather than the OP), most baluns don't use IP compatible signalling. The fact that CAT cable and Ethernet connections are used is incidental. Balun signals won't mix with IP signals or the hardware used for IP signalling such as switches. The exception to this is HDBaseT. However, although these signals will pass through switches, its still good practise to keep these in a separate system.]]
Shielded vs unshielded.
Personally, I would avoid using shielded CAT cables unless there's a very strong reason to go down that route. Shielding undoes the benefits of the isolation provided by Ethernet connections because it physically bridges the source and receiver gear.
For grouping purposes, CAT cable and mains cable will live reasonably happily together in a domestic installation. Keep your aerial cables a minimum of 10" (25cm) away from mains and CAT cable where they have to run parallel for several metres. Where the signals have to cross, do so at 90 degrees.
CAT5e vs CAT6
There's a lot made about the extra bandwidth of CAT6, but the fact is that good quality CAT5e will theoretically support Gigabit networking up to around 100m for single cable lengths. In practise, a more realistic limit is 40-45m for single cable runs since cable handling and bend radii and terminations all take a toll on the maximum throughput speeds. Still, 40m is long enough for most domestic installations.
Having said that, the price premium for CAT6 isn't much over CAT5e so long as both are all copper cables, so I'd use CAT6 myself, but be mindful that it needs more careful handling. It won't go as tight round bends and you need to be careful when pulling it not to put too much strain on the cable. Also be aware that clipping or cable tying it too tightly will impact on speeds because it deforms the construction and increases crosstalk noise.
How much speed do I need?
This is another area where it's very easy to get lost down the rabbit hole. Unless you're running some workstation and a huge solid state NAS drive at home, then the chances are that you're not really shifting that much data around your home network, so over-spec'ing the network cable could be a waste of time and money.
The bottlenecks to your file transfer speeds will be things like the speed of the Ethernet ports and network cards in your various devices. A good example is ISP-supplied routers. There's a lot of stuff around that's still 10/100Mbps. If your network uses that as the central switch, then you'll never get the benefit of the Gigabit speeds of CAT5e or CAT6. For this reason, a good Gigabit network switch might be a better choice as the central point in your network, and then link the router to that with a patch cable.
This brings me neatly to the next point - patch cables. Most are crap and act as another bottleneck to throttle network speed. You're far better off using some of the network cable you bought for the install' and making up your own leads than relying on the promises of online vendors.
Here's some evidence.
Beyond this there are hardware limitations such as hard drive speeds and the data bus speeds in PC hardware.
Now lets relate this back to the speed of your internet connection, and what you're likely to use where speed is important.
The rise of data streaming video services such as Netflix, Amazon Prime, Disney+, NowTV, BBC iPlayer, BT Sports and the rest won't have gone unmissed by many. To go with this, there's also a lot of stuff available in 4K UHD, and that means it needs a bit more oomph from your broadband supplier if you want to get the full beans experience.
Currently, the most data-hungry streaming feed is BT Sports Ultra HD service. BT recommend 44Mbps as your ISP service speed. In reality, the service speed is closer to 30Mbps. That means data moving in your network at 3% of the Gigabit (1000Mbps) network speeds capable via CAT5e and CAT6 cable. Even 10/100 Fast Ethernet devices have at least double the speed capacity.
Things change a bit when you're moving data files or downloading from the net, but since those activities can be completed in the background then the speed is more about convenience rather than necessity. A single physical drive with moving platters will generally give you around 30-40MBps (an MB with a capital B is a MegaByte, and it's 8x the size of a Megabit which is what your internet speed and network speeds are measured in.) The equivalent network speed is 240-320Mbps; still nowhere near Gigabit speeds. Internet download speeds will be governed by the speed of the servers (out of your control) and how fast your ISP data service is by the time contention is taken in to account. You can purchase more speed, but it's not possible to control how many other people are online at the same time all using the same fibre line to your local cabinet.
When CAT cable isn't CAT cable at all
One big potential trap for cable purchasers is fake CAT cable. Anything with
CCS or
CCA in the product description isn't an all copper cable. CC stands for '
copper
clad'. The S or A is for steel or aluminium. These cables then are cheaper base materials with an anodised layer of copper.
Here's the important bit - There's no specification of CAT cable that allows for anything other than 100% copper cores. If it's not solid copper, then it's not a true CAT cable.
(
TL;DR) Go with good CAT6 (all copper cable, not CCS or CCA) from a reputable brand. If cost is prohibitive, drop down to a good CAT5e rather than use a poor CAT6 cable. Make up your own patch leads; they'll often be better that cheap off-the-shelf alternatives. Be careful how you pull, clip and terminate cable; network cables don't like being crushed or bent. Physical separation (10" or more) is better than compromising the network isolation with shielded cables. Check the specs of any devices such as baluns before committing to cable runs.
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