Cable LAN issues + Cable Groung Loop Isolator

Mika 3 years ago updated by Connie Anderson 3 years ago 10
First of all, thank you for your informative pages about the electricity-based problems. We just got a fiber connection installed by a local provider and there seems to be some trouble with it. We wanted to reduce wireless connections and as a part of the project, I also built a wired network all over the house. When the cables are connected to a laptop, a tickling feeling comes to my forehead and hands. The same thing happens to my wife. The local provider nor the electrician has not been able to help. We haven't had such issues with the 4G-routed / Wifi.

The fiber and network routers are installed in another building and then we have a RJ-45 connection to our house. Currently, we have CAT 6 UTP cables but these can be changed to shielded ones. Also, the network cables are partially installed next to the power cables which might be an issue. 

We have a meter in use (Cornet ED88TPlus) and have done some measurements, but I could only find a fault in the VOIP system that was a part of the delivery. It actually gives high EMF rates to the cables but switching VOIP off does not remove the symptoms.

Could the ground loop isolator ( https://www.electrahealth.com/Ethernet_Ground_Loop_Isolator.html ) fix the issue or do you have some other guidelines where to seek next?

With Best Regards Mika / Finland
Under review


I will get this to Shaun right away and see if we can get you some answers. In the meantime, would you be agreeable to allowing me to make this a public post as once we get an answer to this question it could potentially help many others as well?

- Seth

- Electrahealth Team


Sure, that can be done. 

Best Regards Mika

I would definitely get some good quality shielded cables to begin with.  Ensure each cable is properly ground at ONE end only.  So if a cable is connected to a metal switch/hub/router, then it is recommended to use the Ground Loop Isolator at the switch/hub/router.  Then ensure the cable is grounded to the computer AT the computer.  The easiest and most effective way to do both of these things with a laptop is to use the Ultimate USB/Ethernet adapter.

All laptops need to be grounded once and once only - that is the best method.  Desktops are already grounded.

There are more things you can try.  I have a number of other strategies available if you would like to do one 20-minute consult session, and we could go over those things.  We could actually do it by email as well.

I hope this is helpful and we can solve your problem quickly!  That is definitely not the way to live when you are experiencing symptoms.

ElectraHealth Principal

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Hi Shaun,

I am using two of your ground loop isolators, for my two desk top computers and they definitely do help to take the edge off my symptoms when I am at the computer :)  

My question for you is,  if the router has metal in the port but it doesn't have a grounded electrical plug (just two prongs not three), then is it actually grounding?  

Thank you!


Hello again, I forgot this question:  if I use a ground loop isolator in the desktop (so the ethernet cord plugs into the isolator which plugs into the Ethernet port of the iMac), then is that sufficient to deal with any ground loop I may have from the router or modem (which do both have metal ports)?  Or any ground loop created by the grounding adaptor I have hae had on the ethernet connection for a long time?  Obviously, the iMac is grounded by its power cord...  I have a feeling I have a ground loop going here...  but does the isolator protect me from it or not?  



Hi Connie - yes!  The isolator will protect and break the ground loop in this case!  This is exactly what you want to do - you are absolutely right.  The isolator can also be plugged-into the modem/router/switch port.  Then the long Ethernet cable can go to the computer.  That is how we usually do it.  Either way will work though - the isolator can go into the back of the grounded computer or it can go into the grounded switch/modem/router.

ElectraHealth Principal

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Thank you for your helpful reply!  I'm glad to hear that my set up is good.  Why do you usually put the isolator in the grounded switch/modem/router as opposed to the computer?  Does it have some advantage over putting it into the Ethernet port of the desktop computer?   

Would you be able to answer my other question (in the first message) as well:  

 if the router has metal in the port but it doesn't have a grounded electrical plug (just two prongs not three), then is it actually grounding?

A router/switch with metal ports may or may not be grounded.  If it has 3-prong power, then it is almost certainly grounded.  If it does not, like in your case, then it will only be grounded if another device that is grounded and has a metal port is plugged into it with a shielded Ethernet cable. Sometimes cable modems are grounded and pass the ground from the coaxial round cable wire to its metal Ethernet port - sometimes.

When in doubt - test it.  You can use a body voltage kit to test it.

We usually like to ground the Ethernet cable going to a computer at the computer.  That way the computer and the Ethernet cable are definitely at the same electrical potential.  But it doesn't really matter a whole lot - it just may be optimal this way.

ElectraHealth Principal

Click here for personal 1-on-1 help with me

Thank you for your helpful and prompt reply.  I have a body voltage kit, but have never used it to determine whether something is grounded or not.  My body voltage at my computer is quite low (0.085V with hands on the mouse and keyboard, seated two arms length away from the iMac).  How would I use it to determine grounding?  As soon as it is ungrounded my body voltage would increase significantly?  Or would I use it a different way (I know that I can use the multimeter on a different setting to see how much juice our car battery has left in it...)

I'm hesitant to remove the grounding adaptor from the ethernet cord and just let it ground via the computer, as adding that to my computer setup  enabled me to get back onto my computer when I got to the point where I couldn't be online AT ALL.  So it clearly did something (not sure what) that helped, and that was before I had the grounding loop isolator!  


One more question:  if I plug my printer cord into one of the the USB ports on this device, will it ground the printer for me just as it is grounding the ethernet cord?  (The printer is not grounded via its two-pronged power plug now).  I remember reading somewhere on your website about printers needing grounding, but I can't find that now in any of the product descriptions (maybe it was in a forum answer).