The shift to Ethernet, and subsequently, Ethernet/IP technologies has taken the automation world by storm in recent years. Gone are the days of proprietary type network protocols such as Data Highway, Data Highway Plus, DirectNET, to name a few. Networking between automation controllers and IO is now largely accomplished by leveraging Ethernet technologies and its media.
As an automation engineer working in modern industrial facilities, knowing your network cabling types is a must. In this article, I’ll provide an in-depth look at the different Ethernet network cabling types on the market today. As well as some that are still in the beta testing (development) phases. Be sure to continue reading and bookmark the page for future reference.
I still remember the days when running 2 inch conduit was normal to run control and interlock control wires to and from enclosures. Perfectly bundled wires that enabled machines and devices to communicate discretely over 120VAC connection, it was almost a work of art to see when done correctly. I know some of you seasoned veterans out there reading this know exactly what I’m talking about.
These large bundles of conductors and multi-conductor cables has in almost all instances been replaced by Ethernet network cabling, an Ethernet enabled Remote IO adapter on the other end, and perhaps a few 24 VDC power conductors for good measure.
Since Ethernet technologies are largely taking over our manufacturing facilities, I thought it relevant to do an article that takes a closer look at the different Ethernet network cabling types you’re likely to encounter and are most likely installing like spider-webs all over your plants today.
Different Categories of Ethernet
While the differences in Ethernet cable types and technologies can be very easy to overlook to the untrained eye, it is important to understand the difference between them to ensure you make the right choice for your next installation.
Network Cabling Types
Now that we have a solid foundation with respect to the different Ethernet categories, let’s do a deep-dive into the different network cabling types that you’re likely to encounter in the field.
Category 3, or Cat3, as it is more commonly known is a very early generation of Ethernet cable. It is a type of unshielded twisted pair (UTP) cable that was widely used for voice and data communications in computer and telecommunication networks. It is still used for two-line telephone systems, alarm system installations and 10BASE-T networks.
Cat3 Ethernet cable can have 2, 3 or even 4 copper pairs (although uncommon) and caps out at a maximum frequency of 16 MHz. For this reason, Category 5e (Cat5e) has been the default Ethernet cable of choice in most industrial facilities for its faster speeds and higher frequencies.
Cat5 Ethernet cable gave us the ability to transmit data up to 100 megabits per second (Mbps) at a maximum distance of 100 meters. The problem with Cat5 cabling, and likely the reason its life was short lived, was due to the lack of a stringent set of standards and its susceptibility to electro-magnetic interference (EMI) or noise. This caused many issues with network latency errors caused by cross-talk and other noise related problems. To improve on Cat5, an enhanced version Cat5e was introduced.
While Cat5 and Cat5e are virtually identical looking cables if held side-by-side, the construction of Cat5e made significant improvements in its ability to mitigate the effects of EMI. The “e” in Cat5e stand for enhanced and its in the production of the cable that these enhancements are seen.
Both Cat5 and Cat5e use twisted pair wiring, however, Cat5e adopts more stringent IEEE standards making it twisted pair wiring tighter, and more consistent throughout a given length of cable, therefore, more impervious to noise and problems suffered by its predecessor, cross-talk.
Cat5e is the most common type of Ethernet cabling used in industrial manufacturing facilities today for machine connectivity. The reason is its cost/meter is low, it is highly flexible making it easy to install in conduits and cable trays, and it supports a maximum frequency of 100 MHz.
In theory, Cat5e will support Gigabit Ethernet or 1000 Mbps of throughput. That said, while theoretically it is possible to achieve a gigabit transmission speed, it is not well suited for applications demanding this type of throughput, particularly in noise ridden industrial facilities or over long runs. Like Cat5 it can be run up to 100 meters.
Cat6 cable was introduced to provide transmission throughput speeds of up to 10 Gbps at frequencies that can reach 250 MHz. Cat6 cable is physically a much heavier cable than Cat5e because of its higher “twist density”. Cat5e has and average twist density of 1.5-2 twists per centimeter, with Cat6 cable having 2 or more twists per centimeter.
Cat6 also standardizes thicker sheathing than Cat5e with a heavier “cable spine”. The downside of Cat6 is that while standard Ethernet supports distances of up to 100 meters, Cat6 cable only supports 35-55 meters (depending on cross-talk) when transmitting at 10 Gbps (gigabits per second) speeds.
Cat6a is a newer variant of Cat6 cable with the added capacity to support a 10 Gigabit Ethernet connection at a distance of 100 meters (versus a maximum of 37 meters with Cat6). Cat6a also supports twice the bandwidth frequency of Cat6, topping out at 500 MHz.
Cat6a also improves on its ability to mitigate alien crosstalk (ATX) due to its more robust sheathing. This more robust sheathing makes the cable physically larger, more flexible, and therefore ideally suited for Industrial facilities.
Cat7 is relatively new to market and again tries to improve on its predecessor Cat6a. While I personally haven’t seen Cat7 deployed in Industrial environments as of the time of writing this article,
Cat7 also supports 10 Gigabit Ethernet, however, theoretical testing shows that it can transmit up to 40 Gb to distances of 50 meters, and 100 Gb at distances of 15 meters. This may make it an ideal cable for use in large data centers or enterprise type networks.
Cat7 improves on the shielding of Cat6a to reduce the effects of alien crosstalk and signal attenuation. The downside of this cabling is that it is quite rigid when compared to previous generations of cabling making it more difficult to work with. With all of these improvements, performance wise it is likely overkill for manufacturing or automation network environments, with the exception of maybe IP cameras or AV setups that demand fast throughput. That said, I would still likely opt for Cat6a cable from a price versus performance standpoint.
But wait, there is another player in the arena of network cabling types – Cat8! Yes, while Cat7 still has not received official telecommunications approval, Cat8 is currently in development. If you’re interested in the latest trends and the future of Ethernet technology, check out the Ethernet Alliance 2019 Roadmap for Ethernet technologies. This website provides good information regarding where the technology is going.
Consider this before buying any of the network cabling types:
Before you ultimately decide on purchasing any of the network cabling types covered in this article for your next automation project, let’s carefully consider a few more important aspects of your cabling and its installation or environment.
Shielded (FTP) vs. Unshielded (UTP)
One of the decisions you’ll need to make with any of the network cabling types listed above is whether or not you require shielded (FTP – Foiled Twisted Pair) or unshielded (UTP – Unshielded Twisted Pair) cable. Let’s discuss what shielding vs. unshielded network cabling will do for you.
If you are installing your network cabling in “noisy”, high frequency or “heavy magnetics” (lots of heavy load switching) type environments then I would almost always recommend going with a high quality shielded (FTP) network cable. Of course depending on the type of bandwidth and throughput you require, I would recommend at a minimum a Cat5e cable all the way up to a Cat6a cable. Here are a few network cabling types I found on Amazon that would meet the standard of quality I would expect:
- Extreme Cat5e Cable Shielded (FTP) w/ Solid Copper Conductors, UL Listed
- Cat6 Plenum Shielded, 23AWG Solid Bare Copper, 550MHz, ETL Listed, Overall Foil Shield (FTP)
- Cat6a 650MHz 10G Shielded Solid Plenum FTP 100% Pure Copper, 1000Ft
Another method of shielding would be of course to pull your network cabling types through conduit as the conduit itself will provide a level of shielding from electro-magnetic interference (EMI). From a cost perspective, you would have to do the analysis to see which way is cheaper, shielded (FTP) cable run in “free-air” or unshielded (UTP) run through conduit. I will leave this calculation up to you!
Narrow Down Your Requirements
It may be helpful to narrow down the network cabling requirements of your project by answering a few simple questions:
- Does your project require direct-burial network cabling types or UV protection?
- How close to high frequency power lines, machines, or magnetics are these network cabling types likely to be run?
- Are your network cabling types likely to be pulled through conduit, walls, plenums or placed in free air?
- Is flame resistant cabling a requirement for your specific project?
Each of the network cabling types listed in this article come in a variety of insulation, sheathing, wire size, and shielding. This is why it is so important to understand the differences before you commit to a purchase. Be advised that depending on the requirements, the quality of the network cabling, and the standards or markings needed, can drastically impact the price. Expect to pay anywhere from $100 to $600 or more for a reel of 1000′ of cable in some instances.
Final Words on Network Cabling Types…
Well I hope I’ve given you some things to think about when it comes to network cabling types and this article has provided you with some good tips to make an informed decision.
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