The characteristic AWG stands for American Wire Gauge but what's its importance in networking?
AWG stands for American Wire Gauge. This is something interesting that I learned today (at least what the abbreviation means).
In terms of networking it represents the wire diameter of an Ethernet cable or probably any cable. Contrary to expectations, the higher the number the thinner the wire is. There are also a bunch of characteristics related to it that I don't understand.
It has a total of 44 possible values (1-40, plus 0, 00, 000 & 0000) and according the TIA 568-C.2 standard Ethernet patch cables should consist of four balanced twisted-pairs of 22 AWG to 26 AWG (0.64516mm to 0.40386mm) solid or stranded conductors.
I'm wondering if smaller or bigger values are better. Is the signal better, or the tension higher, and what's the importance of characteristics such as:
+-----+------------------+-------+-----------------------+-------------+-------------+
| | Diameter | Area | Resistance | Max Current | Max Freq. |
| AWG |------------------+-------+-----------------------+-------------| for 100% |
| | [in.] | [mm] | [mm²] | [Ω/1000ft] | [Ω/km] | [Amperes] | skin depth |
+-----+--------+---------+-------+------------+----------+-------------+-------------+
| 21 | 0.0285 | 0.7239 | 0.41 | 12.8 | 41.984 | 1.2 | 33 kHz |
| 22 | 0.0254 | 0.64516 | 0.326 | 16.14 | 52.9392 | 0.92 | 42 kHz |
| 23 | 0.0226 | 0.57404 | 0.258 | 20.36 | 66.7808 | 0.729 | 53 kHz |
| 24 | 0.0201 | 0.51054 | 0.205 | 25.67 | 84.1976 | 0.577 | 68 kHz |
| 25 | 0.0179 | 0.45466 | 0.162 | 32.37 | 106.1736 | 0.457 | 85 kHz |
| 26 | 0.0159 | 0.40386 | 0.129 | 40.81 | 133.8568 | 0.361 | 107 kHz |
| 27 | 0.0142 | 0.36068 | 0.102 | 51.47 | 168.8216 | 0.288 | 130 kHz |
+-----+--------+---------+-------+------------+----------+-------------+-------------+
Where I live, I only see cables rated AWG23, AWG24, AWG26, AWG26/7. Not sure what to pick because I have no idea what the differences are.
Is there a right diameter for a specific situation?
Conduit, signal resistance, ohmic resistance (DC), impedance (AC), Power over Ethernet - how are these things related and how do they influence the network and the devices I am using.
Basically, how do I know which AWG is the best?
Solution 1:
In general, AWG is used for ampacity (i.e. how much amperage you can force down a conductor for a given wire diameter before it starts to heat). It is also a gauge for resistance (DC) or impedance (AC). When talking about resistance or impedance, it usually has to do with voltage drop. In the case of Ethernet we are talking about signal loss (voltage drop over distance).
Total distance (Signaling)
When referring to distance, a higher AWG rating (smaller diameter) will have a greater signal attenuation for the same distance compared to a lower AWG rating (larger diameter).
Conduit
In situations regarding conduit, when dealing with a conduit that has 80-85% of its total capacity used, you may have to use a smaller diameter cable.
Power over Ethernet
Power over Ethernet (PoE) has become extremely popular. Here is a quote regarding AWG sizing from Belden.
No longer confined solely to VoIP phones and security cameras, more types of powered devices are beginning to call for Power over Ethernet connections. And these devices are requiring higher power levels, too. Wireless Access Points, digital signage, videoconferencing systems and laptops are all increasing the amount of power running through cables. In fact, a new PoE standard, IEEE 802.3bt, supports up to 100W of power per cable.
But higher power levels running through a cable can cause performance issues – namely by making the cable hotter. And when the cable gets hotter, insertion loss increases. This escalates your chances of your business experiencing a productivity killer – downtime – and may also damage the cable itself.
As you can see it has to do not only with signal loss, but also power drop vs distance when dealing with PoE. And if you try to force too many amps (i.e. the power draw of the device connected to the cable) down it, it may also heat up or damage the cable if the AWG size is not rated for the amperage. For a given situation, you may be able to squeeze that last little bit out of your conduit with a higher AWG size. (With help from a lubricant.)
Do you need PoE over the cabling? If the answer is yes, and this is permanent cable (not patch cords), then you would want solid not stranded cabling, with the lowest number AWG you can purchase.
References:
https://www.belden.com/blog/digital-building/3-reasons-why-power-over-ethernet-demands-cat-6a-cable
https://blog.tripplite.com/whats-the-difference-between-24-awg-26-awg-and-28-awg-network-cables/
Solution 2:
In terms of networking it represents the wire diameter of an Ethernet cable or probably any cable.
AWG is as the name suggest an American system for measuring the size of wires. If you are in America you will probably find nearly all wires are measured in this manner. If you are not in America you will likely find other systems are also in use for many types of cable.
Larger numbers mean smaller wires, I belive this system comes from the way wires are made. Each die reduces the size of the wire slightly, so a smaller wire is made by pulling the wire through more dies.
For stranded cables the quoted AWG number is normally not an actual diameter but an "equivilent" diameter of solid core wire that would give the same cross-sectional area.
In general a larger wire (lower AWG number) will have lower losses and will heat up less if power is transmitted through it, on the downside it is likely to cost more and be less flexible. If the wire gets too large or small there may be problems with termination compatibilities hence why the specification for "CAT" cables sets both an upper and a lower limit.
There can also be problems if the wire size gets too big compared to the wavelength of the signals but I don't think this is a problem at anywhere close to the wire sizes and frequencies used for Ethernet.