Cat5e and power-line interference

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fbiguy

Limp Gawd
Joined
Nov 17, 2004
Messages
168
I just bought a house and while remodeling decided it would be best to get my cat5e put in. Tonight the guy running the cable finally finished up. My goal is to have gigabit speeds on these lines, thus the cat5e.

In my previous research I often came across the advice to keep the cat5e cable away from power lines (going to the lights/fans/etc) whenever possible, and if you had to cross one, to do it at a 90 degree angle. And the optimal distance from power lines being 3+ feet.

Well turns out my house was a b*tch to wire and they had to get right into bed with some of the electric wires. I have some pictures, and I just wanted advice. Is there any way to shield these lines?

In this picture you can see the Cat5e cables resting on the AC vent. I'm told that the vibrations are mainly what can deteriorate signal, so I plan to pad this and get is far from the vent as possible (probably 4-5 inches).


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The remaining pictures show the cat5e being run by power. Obviously there are multiple points of "contact" and i'm concerned as to how it will effect my signal. What can i do to shield the cat5e?

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If i were to place some sheet metal inbetween the cat5e and the power, would that shield against issues coming from the power? and would grounding that shield to the raft actually ground it or would it need to be tapped into the actual ground on the electctric wire?
 
the EIA/TIA standard is minimum of 6 inches between the two...some form of shielding would help indded, normally they just use shielded cat5e for stuff like this.

Look at it this way, hook it up first and if it sucks then try to shield it.
 
I would guess that won't interfere to badly. However, in that situation, I would have run Shielded cat 5. A bit more expensive, but in that situation it would have been worth it.

Not sure what else you can do from this point forward ( but there has to be something ), but I figured I'd toss that out for anybody searching and finding this post.
 
Kaos said:
the EIA/TIA standard is minimum of 6 inches between the two...some form of shielding would help indded, normally they just use shielded cat5e for stuff like this.

Look at it this way, hook it up first and if it sucks then try to shield it.
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I'm not really sure how to test the lines though; my computer system is out of commission until I move in (watercooled). And I’m not sure how I could test. I'd want to resolve any issues before I patch up all the drywall just in case I need to pull out a line and run it again.

XOR != OR said:
I would guess that won't interfere to badly. However, in that situation, I would have run Shielded cat 5. A bit more expensive, but in that situation it would have been worth it.
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I was going to go the shielded route, but read that in order to have a truly shielded system, the NIC on each computer connected to my network would need to be "shielded" or in other words, would need to dump off that interference.
 
I had to cross and or route with power in my house. I havent noticed any slow down or issues. 8 out of the 12 PC's are running gig, so while I havent had any experiance at work becasue we strictly follow standards, I havent seen any issues in with the 8 I am running at Gig at home. I can take a look at port counters when I get home to see if I have any errors though.
 
moetop said:
I can take a look at port counters when I get home to see if I have any errors though.
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That would be cool if you could.

I have been searching google this morning, and have been unsuccessful in finding any solution or a hint torwards a solution to shielding the wires post-install...
 
You may or may not experience any problems. I have seen installs in the past that others have done and they have the Cat5e laying on top of flourescent(sp?) lights and yet we had no issues with the network what so ever. On the other hand I have come into a job to "fix" a network and after some troubleshooting we find that the cable is laying on top of light fixtures. We move or replace the cable and it fixes almost all of the problems.

You may be ok to leave the wire where it is. Typically when you are installing wire that close to electrical and lighting you would use a shielded Cat5e.

Hope this helps
 
it really depends on a lot of things, how well the wire conforms to the CAT5e standard, how sensitive your network cards/switches are to line noise... also the length of the run will make a difference also, if you are near the maximum, them you may expierence problems, but chances are if your runs are <150ft you shouldent have any issues
 
Axeldoomeyer said:
You may or may not experience any problems. I have seen installs in the past that others have done and they have the Cat5e laying on top of flourescent(sp?) lights and yet we had no issues with the network what so ever. On the other hand I have come into a job to "fix" a network and after some troubleshooting we find that the cable is laying on top of light fixtures. We move or replace the cable and it fixes almost all of the problems.
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I guess its down to testing, i'm not sure how i could do that with my situation. As i dont have access to any computers with gigabit jacks. My desktop has one, but its out of commission until i can gets its water cooling back up (ie move into the house).


FLECOM said:
but chances are if your runs are <150ft you shouldent have any issues
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Thats good to hear, Its a townhouse, the longest run "as the crow flies" so-to-speak is about 80-90 feet + some for the bends and going up walls etc. I'm pretty sure the longest run is under 130-140ft
 
Mkay

Only 2 ports had errors. One is collisions, which I suspect is my hauppauge MVP only synching at half duplex, and a linksys pap2 (voip FXS adapter), which is directly wired through a 2 foot cable, so that is not related to any powerline.

As far as I am concerned I do not see any issues related to crossing any power cabeling..
 
Axeldoomeyer said:
I have seen installs in the past that others have done and they have the Cat5e laying on top of flourescent(sp?) lights and yet we had no issues with the network what so ever. On the other hand I have come into a job to "fix" a network and after some troubleshooting we find that the cable is laying on top of light fixtures. We move or replace the cable and it fixes almost all of the problems.
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Magnetic or electronic ballast makes a big difference. The supply wiring makes a difference too. Armoured cable creates much less interference than non-metallic (aka loomex/romex).


fbiguy said:
was going to go the shielded route, but read that in order to have a truly shielded system, the NIC on each computer connected to my network would need to be "shielded" or in other words, would need to dump off that interference.
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Depends on what you are trying to accomplish. If the only source of interference you are concerned about is the AC wiring in the walls, you can ground the shield at one end of the horizontal cabling. After all, the shielded-type RJ45 on your nic finds it ground back through the 3rd prong on your PC powercord. (Disregard this idea if you have the orange, isolated-ground receptacles).
 
For the sake of future Googler's, here is what I found.

Disclaimer: I am not trying to slander anyone's advice, I usually feel pretty confident in my internet research, but on this subject, I’ve had a very hard time finding solid ground as far as reference material (i.e. research papers, tests, etc).

I posted this question on another forum, and a member of that forum suggested wrapping the cat5e in tinfoil (and i came here to find killa62 had suggested this as well) and grounding the tinfoil. Which would basically be the same as shielded cat5e, in theory.

After my numerous Google inquiries and not turning up anything of use, using the grounded-tinfoil idea seemed like the best option to me.

Last night I headed off to Home Depot to get the wire for grounding the tinfoil. And while there I was helped by one of the night guys who happened to work for SRP, my electric utility company.

Now the one caveat in his advice is that as far as I’m aware, this gentleman helping me has never worked with cat5e. So perhaps his estimations are inaccurate.

Regardless, here is the story.

He suggested against tinfoil in the ceiling, as it poses a major fire threat. He may have been thinking I was going to wrap the power cord, but either way, not something I want to risk.

I related to him my paranoia of any EMI issues. And he said the EMF (electromagnetic field/EMI) emitted from the power cables used in my house was about 1/8 of an inch around the wire, maybe a bit less.

He suggested wrapping a rubber material around the power cord in the area’s that it is in close proximity to the cat5e lines.

Now I don’t know right one way or the other on this issue. But this is easier and plays to my situation. So I’m going to do this, and cross my fingers hoping it comes out okay.

I’ll be sure to get pictures after I’m done wrapping.
 
moetop said:
Mkay

Only 2 ports had errors. One is collisions, which I suspect is my hauppauge MVP only synching at half duplex, and a linksys pap2 (voip FXS adapter), which is directly wired through a 2 foot cable, so that is not related to any powerline.

As far as I am concerned I do not see any issues related to crossing any power cabeling..
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thanks for checking that out. I'll have to follow up with you and do the same tests on my network once its all up and running.
 
Using Gigabit you should see a result immediately. Gigabit is auto-negotiation only and cannot be set in the properties of the NIC. If the Gigabit Connectivity is affected by EMF typically it will not connect, or if it connects it will be at 100mbps. I have seen some weird things with gigabit EMF and cable length. The max length is 100 meters; howver, I have seen GB fail somewhere around the 80 meter mark becuase of EMF. When the PC was connected it would connect at GB but after a few minutes it would drop connection and reconnect at 100mbps.

Once you have all of your computers connected run Etherreal on them and whatch the packets. This will help determine if EMF is interfering with your network. Also, while you are running Etherreal do some very large file transfers as well as small transfers. Hopefull it will go smoth and everything will run in GB.

Let us know the outcome. I would like to know if there is any problems.
 
fbiguy said:
He suggested wrapping a rubber material around the power cord in the area’s that it is in close proximity to the cat5e lines.
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This will do basically nothing about EMI for data cabling. From a utility (high voltage) standpoint this is suitable as more rubber, silicone, etc increases insulation value in situations where EMI is so high that it causes normal air to break down and become ionized, causing an effect called corona which is damaging to the high-voltage conductors themselves.

Metal is the only way you are going to redirect (notice I didn't say block) EMI away from sensitive data equipment and cabling. Part of redirecting it is making sure it has a path to ground.
 
u2slow said:
Metal is the only way you are going to redirect (notice I didn't say block) EMI away from sensitive data equipment and cabling. Part of redirecting it is making sure it has a path to ground.
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Yeah, the rubber that i have is just to insure space between the cables, hopefully helping them avoid the IME field...

Thanks for the instructions Axeldoomeyer :) I'll be back with results. (DTBD)
 
i said tinfoil, not aluminum,
tinfoil doesn't burn, aluminum foil does burn
dont worry about the tinfoil
 
fbiguy said:
If i were to place some sheet metal inbetween the cat5e and the power, would that shield against issues coming from the power? and would grounding that shield to the raft actually ground it or would it need to be tapped into the actual ground on the electctric wire?
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I was wondering if copper pipe would work, since it has a fairly low resistance. Its also easy enough to bend and work with using your hands.
 
killa62 said:
i said tinfoil, not aluminum,
tinfoil doesn't burn, aluminum foil does burn
dont worry about the tinfoil
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wait, what? i cant see where anyone mentioned aluminum...


Also as an update, i was just at my house working on this. I kind of got frusterated. I found a few area's where it seemed like the guy who installed it was trying to hide stuff. So it just makes me wonder where else he may have jury rigged it.

I still wrapped the wires, but i'm not as confident. One cat5e in particular was routed in the same tight confines. I traced it to the outlet, and marked it, so i'll be able to test that line to see if its different from the others.
 
killa62 said:
i said tinfoil, not aluminum,
tinfoil doesn't burn, aluminum foil does burn
dont worry about the tinfoil
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I want to see this 'tinfoil' you've got that isn't made of aluminum. :p
 
u2slow said:
I want to see this 'tinfoil' you've got that isn't made of aluminum. :p
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oh riiiight, so was your first reply sarcastic? I'm usually pretty good at picking up on that stuff :rolleyes:
 
fbiguy said:
oh riiiight, so was your first reply sarcastic? I'm usually pretty good at picking up on that stuff :rolleyes:
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Sorry, no. Post #12, and #17 are not sarcastic.

I was under the impression that all 'tinfoil' was made from aluminum.
 
fbiguy said:
wait, what? i cant see where anyone mentioned aluminum...


Also as an update, i was just at my house working on this. I kind of got frusterated. I found a few area's where it seemed like the guy who installed it was trying to hide stuff. So it just makes me wonder where else he may have jury rigged it.

I still wrapped the wires, but i'm not as confident. One cat5e in particular was routed in the same tight confines. I traced it to the outlet, and marked it, so i'll be able to test that line to see if its different from the others.
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I have a bad feeling you are wasting your time. Aside from the chances being slim that you even have an issue, if you tie it to house ground and you ever have any wiring issues where interference is going through the ground now you have just created a nice little interference blanket for your cat5. On the other hand when your network starts having problems you will know you have a household grounding issue.. :)
 
if you are really so worried just put all your cat5e inside of a conduit and ground that, or better just go with fiber, its not that expensive anymore...
 
just as an update, and sorry about the confusion on aluminum/tin-foil.

I found some area's that the guy running the cable tried to hide. I dont feel like this will cause any issues, but there are several key points in the cable run that were very disappointing to discover.

I forgot to take pictures of the offending area's before patching. :( but I did trace the most offending cable and marked it so i can test it later to see if it does have issues.

ummm, last night my brother and I finished patching the holes that were a result of the electric/cat5 work. 81 holes in all. :eek:
 
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