Residential Bonding and Grounding of Shielded Ethernet Cable Systems

Residential Bonding and Grounding of Shielded Ethernet Cable Systems

Written by Don Schultz, trueCABLE Technical Manager, BICSI INST1, INSTC, INSTF, Fluke Networks CCTT

It is rare to actually need shielded Ethernet cable in a residential setting. Many DIY installers (homeowers) have a perception that shielded Ethernet is “better”. After all, wouldn’t shielded be somehow better than unshielded Ethernet? Well, oftentimes the answer is “no”. Shielded Ethernet does not make your cable any faster. The shielding is designed to mitigate EMI/RFI interference or potential ESD discharges that you know you need to avoid. That said, there are legitimate circumstances for the use of shielded Ethernet cable in a residential environment and they are covered in Ethernet Cable Shielding Types as well as Top 2 Things to Consider When Running Ethernet and Power Cable.

The two most common scenarios where shielded Ethernet cable is recommended in a residential installation are:

  • You are unable to maintain a 8 inch separation distance from “Romex” unshielded AC circuits or electrical panels (common 120/240V)
  • Outdoor runs that result in the cable being suspended above the ground, in the air, between two structures. This could be two buildings or a single building to a flagpole, for example.

So, you might need bulk unterminated shielded Ethernet cable. Just be aware of what you are signing up for. Shielded Ethernet comes with some “penalties”:

  • Higher costs for the cable and hardware
  • More complex termination technique
  • Shielded cable is more difficult to install due to tighter restrictions on bend radius, weight, and reduced flexibility
  • Shielded Ethernet must be bonded to ground

Of the four disadvantages pointed out above, the fourth one about bonding to ground is probably going to cause you some anxiety. Most residential installers are at a total loss as to how to bond shielded Ethernet cable to ground. Even worse, you may have some incorrect preconceived notions about what to do. That is the focus of this blog: How to bond your Ethernet cable so that the EMI/RFI or ESD encountered is channeled safely to your AC ground system.

Getting a Bit Technical for a Moment

This blog will make more sense if we cover some basic terms. There is a large amount of misinformation and confusion about bonding and grounding of anything, not just Ethernet cable shields. Let’s take some information from another blog I wrote about Commercial Bonding and Grounding of Ethernet Cable Systems. The same concepts apply, but on a smaller scale. I recommend you read the commercial blog if you have a moment.

Are Bonding and Grounding the Same Thing?

Nope. They are highly related, though. In fact, one is sort of useless without the other. That is why you see the terms right beside each other when discussing this topic.

People get the terms “bonding” and “grounding” all confused and mixed up. We need to separate the two highly related, but essentially different, terms.

But, here is a hint:

Bonding is more of a process and result, where grounding/earthing is more of a result only. If you are an installer, then you are bonding to ground. If that does not make sense, then I don’t blame you!

What is Bonding?

Generally, the term bonding is the process of establishing a low resistance electrical path from one conductive object to another so that unwanted voltage has a path to ground in adverse events such as:

  • EMI/RFI (Electromagnetic and Radio Frequency Interference)
  • Electrostatic discharge (ESD)
  • Electrical system faults

What is Grounding?

Grounding is also referred to as “earthing”. They mean the same thing. Conceptually, grounding is to establish a zero (0) volt reference potential to earth. The ground is between the earth itself and the electrical system inside your house. Its purpose is to provide an intentional path for fault current, and provide a path for ESD to drain off to. The idea is to equalize the earth’s potential with the electrical system potential, and all equipment or enclosures that are part of that system. Ground rods (called ground electrodes) and GECs (Ground Electrode Conductors) are used for this purpose.

For residential installations you likely won’t have to worry about bonding ladder racks, cable tray, metallic conduit, and equipment racks. So, the main thing you will have to worry about is bonding your Ethernet cable shields to ground and using some sound techniques.

 

It All Starts With the Cable Shield

trueCABLE sells a variation of shielded cable called F/UTP. That means the cable has an overall foil shield and the individual pairs are not shielded. In addition to that foil shield there is a drain wire (tinned copper wire) that makes contact with the cable shield. The drain wire helps you bond your cable shield to the connection hardware.

Shielded Ethernet cable. Cable shield folded backwards and the drain wire wrapped around the shield.

Shielded Ethernet cable. Cable shield folded backwards and the drain wire wrapped around the shield.

Close up view. Cable shield has been trimmed to leave what is needed for a good  bond. Note drain wire wrapped around the shield and jacket.

Close up view. Cable shield has been trimmed to leave what is needed for a good bond. Note drain wire wrapped around the shield and jacket.

Rear of shielded tool-less keystone jack showing bond leaf spring.

Rear of shielded tool-less keystone jack showing bond leaf spring. The cable shield and/or drain wire should make contact with this to establish a good electrical bond with the cable shield.

closed keystone jack

Once the keystone is closed, the cable shield is now bonded. Best practice is to bond BOTH ends of the cable shield.

caution

 Did you know that once your cable shield is electrically bonded to the keystone jack the outside metal of the keystone jack becomes part of the cable shield and drain path? Now they function as a unit. Pretty cool, huh?

Other connection hardware bonding methods:

 trueCABLE Ethernet cable

trueCABLE Ethernet cable

Once your cable shield has been properly electrically bonded to your termination hardware (shielded keystone for example) you will need to continue that bond. How do you do that? Well, there are three ways depending on your equipment and environment:

  • Tool-less shielded patch panel that is bonded to ground already
  • Tool-less shielded patch panel that is bonded to ground already and you also use shielded patch cords to your properly grounded Ethernet switch (best way)
  • Use of a shielded patch cord only to your properly grounded Ethernet switch

What is a properly grounded Ethernet switch? Basically any Ethernet switch which uses a three prong power cord. 19-inch rack mount switches with their own AC/DC internal power supplies fit the bill.

A small desktop Ethernet switch with an external two prong AC/DC adapter (wall wart) is NOT properly grounded! It cannot serve as the path to ground for your Ethernet cable shield. In this case, you MUST separately bond your shielded patch panel to ground with a “ground wire”. Which means, of course, you have to use a shielded patch panel. You may not have expected that.

Essentially, there must be a way for your Ethernet cable shield to drain off to your AC ground somehow. Here are some schematic examples:

Method #1 - GOOD - AC Powered Ethernet Switch (no AC/DC adapter)

  • Method #1 does not make use of the auxiliary bond wire (green wire) that is typically included with shielded patch panels
  • Method #1 absolutely requires an AC powered Ethernet switch, using a 3 prong power cord
  • Method #1 absolutely requires all components like patch cords and keystone jacks to be shielded
  • At the remote wall mounted keystone jack, a shielded patch cord should also be used to the destination powered device to increase the number of bond points to your AC system ground to two

Method #2 - BEST - AC Powered Ethernet Switch (no AC/DC adapter) with Auxiliary Bond Wire Backup

  • Method #2 makes use of the auxiliary bond wire (green wire) that is typically included with shielded patch panels, but you may need to create your own**
  • Method #2 absolutely requires an AC powered Ethernet switch, using a 3 prong power cord
  • Method #2 absolutely requires all components like patch cords and keystone jacks to be shielded
  • At the remote wall mounted keystone jack, a shielded patch cord should also be used to the destination powered device to increase the number of bond points to your AC system ground to three

Method #3 - DC Powered Ethernet Switch Using AC/DC Power Adapter

 

  • Method #3 absolutely relies upon the auxiliary bond wire (green wire) that is typically included with shielded patch panels, but you may need to create your own**. The bond wire is attached to the AC outlet faceplate, below the center screw. See video!
  • Method #3 addresses small 5 port to 16 port residential style Ethernet switches that usually do not have internal AC to DC conversion and instead rely upon external adapters
  • Method #3 requires shielded keystone jacks, but the patch cord from the patch panel to the Ethernet switch does not need to be shielded
  • At the remote wall mounted keystone jack, a shielded patch cord should be used to the destination powered device to increase the number of bond points to your AC system ground from one back to two, if possible

Help! It won’t Reach

Shielded patch panels come with a laughably short bond wire, typically 18 AWG and only about 12 to 16 inches. If the shielded patch panel is mounted in a rack with a rack busbar then this is not an issue, but residential installations don’t typically involve racks, much less fancy and expensive rack busbars.

**You will likely need to create your own bond wire. That is easy to do.

Pick up the following items from your local Home Depot or similar store:

  • 10 or 12 AWG (don’t go smaller than 12 AWG) THHN green stranded copper wire
  • Ring terminals to fit 10 or 12 AWG stranded THHN stranded copper wire
  • Crimp tool to crimp down the ring terminals
  • Electrical wire stripper tool
  • Take note that when selecting the ring terminals, be sure to pick the ones that will accept your wire and also won’t be too big or too small for the screw on the patch panel or the screw on the AC outlet faceplate. You may need two sizes.
cautionYou might wish to pick up a ring terminal variety pack from Amazon or some other retailer. That way you won’t be making 50 trips to Home Depot or Lowes.
Follow this procedure:
  • Cut a length of the THHN stranded copper wire, not to exceed six feet
  • Strip both ends of the stranded copper wire with proper wire strippers
  • The insulation should go right up to the point where the copper enters the ring terminal, but not inside the ring terminal.
  • The copper conductor itself should be long enough and be visible at the end of the “inspection window”
  • Remove the existing bond wire from the patch panel
  • Attach one end of your new bond wire to the patch panel and the other end to the center screw of an AC outlet. See video for how this looks.

Common Questions & Advice

Let’s address some common questions and give some tips that will help you.

Question: “I have been told that you should only ground the Ethernet cable at one end. Is this true?”

Answer: “Sometimes yes, but only if you are seeking to avoid a ground loop. You likely don’t have to worry about this. If you are running shielded Ethernet between two structures that have their own separate AC systems or separate grounding rods installed, then YES, you should worry about what is known as a ground loop. A ground loop occurs when you have actual conflicting AC ground systems. Merely bonding your Ethernet cable at multiple points to the same AC grounding system in a single structure does not create ground loops. Think in terms of ground rods. How many ground rods are involved? If you have more than one with more than one structure involved then you are wise to bond to ground at a single end only.” How To Fix a Ground Loop is a good resource to read more about this topic.

cautionFor single structure Ethernet installations, you want to bond your cable shields to your single AC ground at as many points as possible. The more bonds to ground the better the shield will function.

Question: “What happens if I don’t bond my Ethernet cable shields to ground? Will I damage anything?”

Answer: “This is known as a floating cable shield. That means the Ethernet cable shield is not able to drain off EMI/RFI/ESD to your ground system. You probably won’t have any problems at all, as most residential situations don’t have large sources of EMI/RFI to cause a big enough issue with a floating cable shield. By not bonding your shields to ground you just wasted money and your shielded cable is not actually shielded anymore. Now, there is the slight possibility you will encounter actual trouble by not bonding those cable shields to ground and this can show up as lower than expected speeds or even an ESD event that could damage equipment.”

cautionIf you are considering installation of shielded Ethernet cable and are unable or unwilling to bond the cable shields to ground then opt for unshielded Ethernet cable for your installation. You will save money and headaches.

Question: “Do I need to pound in a ground rod for all of this to work right?”

Answer: “No. Do not do that! Your home already comes with an AC grounding system you can bond to and your AC panel is already connected to a ground rod. If you pound in a separate ground rod you just created an alternate and potentially conflicting point of ground. You can actually create yourself a ground loop doing this. There are rare circumstances where you may need to pound in a ground rod and bond to that, but that is beyond the scope of this blog.

cautionIf your home passed inspection and was built in the last 40 years you should have three prong grounded AC outlets. Check to be sure your outlets are properly grounded by using a three prong outlet tester. If you get a test result that is anything other than “CORRECT” talk to an electrician!

So, there you have it. A subject that has been the source of many questions and anxiety for residential installers finally explained in one spot. With that, I will say…

HAPPY NETWORKING!!

trueCABLE presents the information on our website, including the “Cable Academy” blog and live chat support, as a service to our customers and other visitors to our website subject to our website terms and conditions. While the information on this website is about data networking and electrical issues, it is not professional advice and any reliance on such material is at your own risk.

Cruz December 12, 2022

OMG, this has got to be THE ABSOLUTE BEST EXPLANATION on completing the shield to ground. No article out there has explained it this simple to understand, or completely covered the answer as to whether to ground the network cable at one end, or both ends. You even gave a real life example of a ground loop.
What you said coincides with everything I’ve ever learned as a senior electronics technician with over 35 years experience in the flight test and development of the latest and greatest military aircraft ever made by a major aircraft manufacturer.
When I saw those, otherwise, smart people out there saying that shielded network cable had to be terminated on one end only; I was beginning to wonder if there was something different about network cabling. That is, until I bumped into a very technical article (and difficult to comprehend) by someone else, and before I ran into yours which puts it all into a nutshell.
QUESTION: Is the following method correct?
So I’m assuming that the house end of the Ethernet cable that goes out to the garage, should be grounded to the grounding system of the house, and the other end is to be left un-grounded. In military aircraft, to avoid an antenna effect such as this, while also avoiding a ground loop; instead of floating the shield, we would attach a ground wire to the shield (with the use of a solder shrink sleeve), and ground said wire to the grounding system of the source (house in this case). This way the shield is grounded on both ends; meeting Mil spec EMI standards. Of course the installer would have to use an appropriate connector to assure no one ever accidentally completes the source shield to a 2nd ground source.
Personally, I would use a male shielded connector with an attached ground wire. Then splice onto that wire with a 18 to 20 gauge insulated wire, and attach the other end to a ground at the source location (house). Then attach that male plug onto a wall plate with a non-shielded union. The network shield system in the garage would then utilize the grounding system of the garage.

trueCABLE December 16, 2022

Hey Cruz!
Thanks for all the kind comments! As to your question, you need to bond one end to ground only for this situation. It is not the ideal way of doing it, but it eliminates the possibility of a ground loop and a floating cable shield. Floating cable shields could result in a possible antenna effect but that is mitigated by at least one end being bonded to ground. On the remote end of the cable, you can terminate to an unshielded keystone OR a shielded keystone and then use an unshielded patch cord to mitigate the possibility of a ground loop. You could use your method if you like, but the level of effort required far outweighs any potential benefit. We hope this helps! Please let us know if you have additional questions!

Richard January 05, 2023

Hello, I have a question about running shielded wire throughout my house to my server rack. My server rack is located conveniently next to a subpanel making it easy to bond. That being said, I'm considering running shielded cables to my rack with a bonded patch panel. I have 3 questions.

Do the devices outside my rack connected through the shielded cables require bonding on their end? (Some are switches, access points, and POE cameras.) Do the devices within my rack require a shielded cable connected to the bonded keystone on the path panel or can these be unshielded? Similar to previous question, is it acceptable to use an unshielded patch cable in a bedroom on a wall outlet with a shielded keystone that is connected back to bonded rack?

Ultimately what I'm trying to do is have all the ethernet cables running through the house shielded to a bonded rack but have all the devices that are connected to the shielded wires in the home be unshielded (access points, poe switch, poe camera, etc)

trueCABLE January 05, 2023

Hello Richard!

See my answers below in [BOLD]

Do the devices outside my rack connected through the shielded cables require bonding on their end? (Some are switches, some are access points, and some are POE cameras.)

[In the case of the PoE devices, you cannot bond at the device end. Your only method is to bond at the switch end, which is sufficient given the circumstances. As for switches, an additional bond will occur at the AC outlet through the switch power supply. As long as everything is bonded to the same AC system inside the same structure, you are good to go.]

Do the devices within my rack require a shielded cable connected to the bonded keystone on the path panel or can these be unshielded?

[Up to you. You can make your installation fully shielded if you like. Normally the devices in the rack are already bonded through contact with the rack frame itself, but that is only if you have bonded the rack frame to your busbar (if you are using one) and therefore AC subpanel. If this is not the case, then you can help provide additional protection by using shielded patch cords. Remember that each piece of rack equipment is probably using a 3-prong AC power cord and is getting a bond to ground already. The idea of bonding the pieces of equipment in the rack (and rack itself) to ground via busbar is to equalize potentials, even given all equipment may already be bonded to ground via their power cords. Equalizing potentials is more important in commercial settings than residential since the differences in potentials from one piece of equipment to another could be lethal voltage.]

Similar to previous question, is it acceptable to use an unshielded patch cable in a bedroom on a wall outlet with a shielded keystone that is connected back to bonded rack?

[Best practice is to bond at as many points as possible by utilizing shielded patch cords to end devices and letting each individual device provide an additional bond to ground through its AC power cord. That said, it likely won’t cause any problems if you use an unshielded cable at the remote end of your connection and many items you are plugging in don’t have a three-prong power cord anyway in a residential setting.]

Ultimately what I’m trying to do is have all the ethernet cables running through the house shielded to a bonded rack but have all the devices that are connected to the shielded wires in the home be unshielded (access points, poe switch, poe camera, etc)

[The minimum is to bond the switch end of the cable to ground. Obviously, it is preferential to bond both ends of the cable but given circumstances, this is not always possible. I would say your idea is sound, especially given your residential environment. In a commercial/industrial environment, I would probably take extra pains to be sure both ends are bonded where possible, but in your case, it would be overkill.] *

    1 out of ...