Grounding ethernet

[Brian W Evans]

I am installing a camera outside the door to my shop, due partly to lots of break-ins in my area over the past year. The camera will be POE (power over ethernet) and I have a POE switch and other necessary equipment. I have done this before, so no questions about the install, except that I need to ground the ethernet cable in case of lightning strike. I lost some equipment to ungrounded ethernet cabling a couple of years back in a different location and I don't want to have it happen again.

I have some (Ubiquiti) ethernet surge protectors but there is no real information about how best to ground them. They do not plug in to anything other than the ethernet cable and are therefore not connected to the house's grounding system. There is a screw for attaching a ground wire, which is easy enough, but I don't know where to attach the other end of this wire.

Should I attach the ground wire to my house's electrical system by, for example, opening up an outlet and grounding the ethernet surge protector to the ground wire in the outlet box? If not, where should this wire go?

Thanks.

[Jerome Stanek]

I would get a ground rod and drive it in and ground to that all my phone and cable grounds to a ground rod below my service entrance

[Paul F Franklin]

First, know that e-net surge protector will be a little help in the case a direct strike to the camera, or even a close strike. You would be better protected if you went with a wireless camera with a beefy surge protector on the power source to the camera. It will still be destroyed in the case of a direct or close strike, but at least won't necessarily take out all your other network stuff as it is isolated by the wireless link.

If you need/want to go wired, then your best grounding strategy would be a ground rod near the surge protector. If you connect to the house wiring, you will simply be channeling the surge energy through your house wiring where it can blow up other stuff in the case of a near strike. Still, it would be better than nothing and would provide some protection in the case of a strike that is nearby but not really close.

[Jim Becker]

You need to determine if "grounding"/surge suppression is going to interfere with the PoE before you take that step...I've been out of the business for a couple of years and don't recall grounding ever come up for Ethernet, at least in the commercial environments I was catering to.

[Brian W Evans]

You need to determine if "grounding"/surge suppression is going to interfere with the PoE before you take that step...I've been out of the business for a couple of years and don't recall grounding ever come up for Ethernet, at least in the commercial environments I was catering to.

The surge supressor I have is just a pass-through and is made for POE devices. As I said, I've had a problem with this before and lost a switch and a router to it.

First, know that e-net surge protector will be a little help in the case a direct strike to the camera, or even a close strike. You would be better protected if you went with a wireless camera with a beefy surge protector on the power source to the camera. It will still be destroyed in the case of a direct or close strike, but at least won't necessarily take out all your other network stuff as it is isolated by the wireless link.

I know that a direct strike to the camera is a difficult thing to mitigate but I would like as much protection as possible for my switch and the things attached to it in case of some transient voltage. The camera will be attached to the house, so I don't think it will be more likely to be hit by lightning than my flood lights, for example. For various reasons I am going to stick with the POE camera instead of wireless, so grounding of some kind will be a necessity.

I guess a ground rod might be the best solution, although it will have to wait until spring.

Thanks for the advice.

[Dick Strauss]

Maybe you can put the Ethernet cabling in metal conduit extending close to the camera (or possibly mount the camera directlly to a metal junction box) and connect the other end of the conduit to a separate dedicated ground rod. This way you might give a lightning strike an easy path to ground that doesn't include your house or equipment.

[Arthur Fleming]

I apologize if this isn’t directly related to the info you seek. I am an electrician for a municipality in Mass. We have approximately 250 exterior cameras on the towns 15-20 buildings we maintain. Of those at least 100-150 are digital (as opposed to analog). They are just wired directly from the switch on cat5-cat6 cables (depending on when they were installed). Some of the more recent have a fusable link installed at the camera where the cat6 cable plugs into the link, then a patch cable, exits out the other side and snaps into the camera. In the 2 years I have been working on the cameras we have not had any losses due to lightning. I think the brand name for the usable links is Ditek.

[David L Morse]

My experience with Ditek is like Arthur's, I've had limited but good results using their equipment. There's a lot of good information on their website but you do need to register there to access much of it.

DO NOT ever connect anything to an isolated ground rod, that is, one that is not bonded to your grounding system. It's unsafe for both you and your equipment.

[Dan Friedrichs]

DO NOT ever connect anything to an isolated ground rod, that is, one that is not bonded to your grounding system. It's unsafe for both you and your equipment.

+1. Don't go installing ground rods...

I lost some equipment to ungrounded ethernet cabling a couple of years back in a different location

How do you know that was the cause?

[Paul F Franklin]

DO NOT ever connect anything to an isolated ground rod, that is, one that is not bonded to your grounding system. It's unsafe for both you and your equipment.

All he is connecting to the ground rod in this case is the return side of spark gaps. There is absolutely nothing wrong or unsafe with connecting to a separate ground rod.

[David L Morse]

All he is connecting to the ground rod in this case is the return side of spark gaps. There is absolutely nothing wrong or unsafe with connecting to a separate ground rod.

I see, this is a spark gap device only. So he will still need some kind of protection at the other end of the cable.

[Dan Friedrichs]

Looking at the picture, it sure looks like the metal shells are grounded to the grounding tab?

[Brian W Evans]

How do you know that was the cause?

I never really did any serious digging into the cause, but both components - switch and router - never came back on after a power outage. I had a good surge protector for the power cords and my other equipment, connected to the same surge protector but not to ethernet, was fine. The maintenance guy told me there was some lightning damage in other units in the same building, so my assumption is that whatever killed my equipment came through ethernet cables.

It may be that the whole surge protector thing is overkill for my application but they're cheap and I figured I would rather be safe than sorry.

I'm clearly not an electrician, so thanks for all the advice.

[Ben Grefe]

I would be really surprised if the lightening strike took out equipment directly via the Ethernet cable and it wasn’t the AC system in that location that took a surge. Ethernet is mostly DC signal cable and runs at such a small gauge that a surge would more likely burn it than actually be transmitted. You also can’t ground Ethernet like an AC signal - they run on different concepts of grounding planes. If you were to ground *just* the PoE pair (the ground side) to ‘ground’ you would at best have a marginal DC signal to your remote device (aka, it would work unreliable). At worst it would just not power the remote device.

If you were to somehow couple the signal pairs of the Ethernet cable to ground then nothing would work.

The ubiquity surge protector might work - they’re a reputable brand. However IMO the ‘data line’ surge protectors built into power strips are basically junk.