Correct way to ground STP shielding in home environment ?

[boran]

Hi,

I am looking to install a home network and I would use Cat6a (it has to last at least 20 years) now most Cat6a I find is shielded, no biggie then, but now I am wondering, how do I ground the shield the best.
Most info I find is for datacenters and refers to a grounding bus bar etc.

I have a regular electricity system and all my plugs and wiring includes a ground wire. would it be sufficient that I ensure that this ground wire (which is the house ground) grounds the shielded cat ?

 

[imagoon]

Don't use shielded. Period. "It has to last 20 years" is an over expectation. Things change, you might need to replace it sooner, you might not. Home needs vary from business quite a bit.

Technically it should be grounded at one point (the patch panel) using a copper bus bar that attaches to vertically buried 6 foot long copper rod via at least a 6 gauge cable, isolated from the electrical system ground.

Don't use the ground pins in the outlets. You will likely cause a grounding loop which will give you more noise (and possibly a 'ground short' which can cause a fire) than running unshielded cable.

 

[ScottMac]

I agree with imagoon; improper grounding, degraded grounding (i.e., neglected over time), or missing shield ground will cause far more problems that it ever solved, especially in a home environment.

If you decide to proceed with using shielded cabling, make sure all your other components are of the proper matched type or you will have wasted a great deal of time and money to install an unrated (i.e., Cat-Nothing) system.

Isolated grounding is not necessary; facilities ground is preferred, but it has to be tested and good. Most homes over a couple years old have really crummy facilities ground (more than a couple ohms at the rod), at least around the Chicago area that I've tested.

 

[spidey07]

Don't use shielded, period. There are plenty of 10 gig cat6a manufacturers our there but you should be very particular about the terminations and follow the manufacturer instructions exactly which may take special tools beside a punch tool.

 

[bobdole369]

I am looking to install a home network and I would use Cat6a (it has to last at least 20 years) now most Cat6a I find is shielded, no biggie then, but now I am wondering, how do I ground the shield the best.
Most info I find is for datacenters and refers to a grounding bus bar etc.

There are a number of reasons you don't use shielded cable in the home. The first is that it becomes difficult to properly ground things. If you ground both ends - the shield can conduct, thus making a ground loop that makes more noise than anything. The second is that in a home you don't have things that you might in a datacenter.

20 years from now nobody is going to be using CAT anything cable. It'll be all fiber so 20 years is unrealistically long. Just have a licensed low voltage guy install CAT6a and certfy it for 10gbit. Thats the best you can do today. Don't try to certify it yourself you don't have access to the right stuff.

As for proper grounding - you'll need to bust up your slab or drill through it in the central location where your rack is installed. This should be a central portion of your basement (if you have one), or a central room if you don't have one. In all likelihood your installed electrical ground is insufficient so its best practice to just have your own. So drill into the slab and pound 8 feet of copper into the earth, repair the busted slab, and run 0 or or larger cable straight to the rack. shielded patch panels will use this same ground and you'll ground this end to your horizontal cable runs. You'll attach the ground to your wall plates and thats the end of the grounding.

I also wish to dissuade you from using shielded cable.

 

[Modelworks]

If you have to use shielded cable the easiest way to take care of the grounding is to use a resistor between the shield and the homes ground. That will bleed off any static charges and still provide some shielding . The correct value for cat6 is usually 3.3K but can vary with cable length.

 

[alkemyst]

I am not sure why so many people think STP is the way to go in a home.

 

[imagoon]

I am not sure why so many people think STP is the way to go in a home.

It has more stuff so it must be better?

I think we need more blinky lights, music and arrows pointing at the sticky since we say as much in there.

Our cabling firm hates working with it also and only uses it in heavy industrial. And only when optics won't work for some reason.

 

[Howard]

Sorry for the necro, but thought this was (is) relevant:

http://www.pennington.net/archives/cabling/BICSI_Mythbusting_Shielded_Cabling.pdf

 

[imagoon]

Random thougths / comments:

The shield becomes and antenna "Myth" they tested it fairly oddly in a low noise environment. IE a 1 watt WAP isn't the big issue and most equipment can dissipate that without much issue. Wrap those cables around a 25hp motor and let me know what happens. Also the mention termination on both ends... It is fairly commonly accepted that you don't terminate both ends due to ground reference variations. They fail to mention that part. I have personally experienced incorrect shielding cooking cables in industrial environments due to induced currents on the shield.

Ground loops: See above. Lets see what happens with a ground loop with some actual reverberation power behind it.

Termination time: They assume that all devices use keystones. Patch panels do not often support them (they exist but most places avoid them due to the significant cost for the bracket + 48 keystones vs a 48 port patch panel.) The keystone type also do not allow for patch panel based grounding which is the most common way to "buss bar" the system. Also those tools they show are specific to certain brands of keystones so while they are faster, most people won't want to buy 15 or so of them to use them. The 110 punch is more "universal." So in my opinion they "busted" the "myth" in a very specific case which doesn't bust the myth entirely, just in that edge case.

Hot potato: Never knew any one actually worried about this... Only time I have heard it mentioned is with large bundles of PoE and even then the cables are rated for ~105C or more so I have never seen one that warm before.

EDIT: The above only happens in industrial environments which is why shielded cables are never recommended for residential and 99% of commercial.

 

[rsutoratosu]

Question for OP, where are you installing the wires that you think you need STP ?

Give us your plan/layout and we'll help you run the correct cable and not waste money !

 

[imagoon]

Question for OP, where are you installing the wires that you think you need STP ?

Give us your plan/layout and we'll help you run the correct cable and not waste money !

It's a necro post.

 

[RadiclDreamer]

Using shielded is asking for a giant antenna, you wont be able to install it right. Not a knock, its just a very difficult thing to do RIGHT.

 

[adhdrunsme]

I would definitely use a giant antena

 

[adhdrunsme]

Actually know what the antenna I would have to be at least three times the size of my redacted