Posted: 2/24/2011 6:29:32 AM EDT
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Hey guys, I have a couple questions that I'd appreciate some help with.
I am an electrician, in the past I took some network engineering courses, but I have a lot to learn and could use some help. When I wire a house for networking I run homeruns back to a patch panel located at a central point, then I let the homeowner run patch cables to their router or switch. On the other side of the home run I install RJ-45 female jacks in the wall and let the homeowner run a patch cable to their computer or device, simple. We all know that you're not supposed to splice a network cable, but my question is this, if splicing a cable could be problematic, isn't running the Cat5 to a patch panel also something that can cause problems? Couldn't you possibly eliviate any issues by crimping a male RJ-45 connector right onto the end of the Cat5 homerun to be plugged directly into the router or switch? That would eliminate the female RJ-45 jack as well as the two male RJ-45 plugs on the patch cable. I hope I am explaining this correctly. Basically I am asking why it's looked upon as being so bad to fix a broken cable by splicing it halfway, while it's got the same thing on either end of it. |
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When terminating on a patch panel you are actually displacing the insulation on the wire so the blades in the Jack/Patch Panel make contact with the conductor. Which is why they are called IDC termination (Insulation displacemant contact)
To splice a cat5 cable by using wire nuts and or beanies upset all kind of testing parameters, such as near end cross talk, attenuation, Propagation Delay Delay Skew, Return Loss (RL) just to name a few. If the signal does not reach the work station from all 4 pairs almost at the same time the node will reject and send a signal back to retransmit. Usually u do not crimp an ice cube to cable cause it is solid conductor, can u get solid conductor RJ45, yes. Is it the industry standard, no. hope this helps This is what we use to test Cat5e and Cat 6 cables, scroll down to "supported test parameter" to see all the test that happen. http://www.flukenetworks.com/fnet/en-us/products/DTX+CableAnalyzer+Series/Specifications.htm |
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Thanks for the replies.
dano, I understand that you can't use wirenuts to splice, but you can install rj45 jacks and then connect them with a patch cable. Or put rj45 plugs on each end and connect them with a female to female adapter. That is still said to be wrong, even tho it is basically done at each end, which is what sparked my curiosity. These say that they are rate for both stranded and solid. Do these look good to you, or is there something else better? http://www.techtoolsupply.com/ProductDetails.asp?ProductCode=SKY20896 |
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Ahhh, something I can speak about with a bloated sense of self-importance!
Anyway, there are a number of reasons that the industry standard is to run cable between Jacks, instead of direct with Plugs installed on the ends. 1. Reliability - The terminations on the back of a decent-quality RJ-45 Jack are significantly more stable, reliable, and dependable than the tiny little contacts inside of an RJ-45 Plug. 2. Reliability - Since the cable at the back of a Jack on either end of the wire never moves (ideally...), there is no stress on the connections and they last, essentially, forever. The same is not true of that tiny little Plug on the end of a cable, getting pulled and twisted and shoved through small holes in desks, and etc. Using a short patch cable also lets you replace a bad Plug at the end by simply unplugging the dead patch cable and plugging in a replacement patch cable, no need to get a tool to terminate a replacement Plug on the end of a single long cable. Which also means the secretary can do it herself without having to call the IT guy. 3. Flexibility - If you run a 100 foot cable with a Plug on each end, you have a 100 foot cable. If you run a 100 foot cable to Jacks on each end, you can then add additional length (within the 100 meter limit) at either end by simply plugging in a longer patch cable. 4. Standardization - Standards are their own benefit. You never need to wonder how this particular room or building was wired, they should all be done the same way. There are some more reasons, but those are enough. There are situations where you would terminate a cable with a Plug, but they are just that: Exceptions. They are uncommon, and not called for in day-to-day commercial/residential installations. Good Luck! FluxPrism |
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Excellent information!
One reason I was thinking about doing it was to get rid of the need for a patch panel in a residential setting, that would be a decent cost savings. I also like the idea of less connectors, seems like less chance of problems (the same way as how you're not supposed to splice a cable midway, to avoid problems). |
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those should be good, I am not saying not to do it, shit I have run cable 400ft which exceeds the 90 meter limit and the shit still works. But in my industry I have to follow BICSI standards, so have to do it as Published in the Telecommunication Installation Manual and the Registered Communication Distribution Design Manual
BICSI |
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Quoted:
Excellent information! One reason I was thinking about doing it was to get rid of the need for a patch panel in a residential setting, that would be a decent cost savings. I also like the idea of less connectors, seems like less chance of problems (the same way as how you're not supposed to splice a cable midway, to avoid problems). Yes but if it were my house I would want the patch panel for ease of use. Stick with the original plan. Sound like you are doing it right. |
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Excellent information! One reason I was thinking about doing it was to get rid of the need for a patch panel in a residential setting, that would be a decent cost savings. I also like the idea of less connectors, seems like less chance of problems (the same way as how you're not supposed to splice a cable midway, to avoid problems). Yes but if it were my house I would want the patch panel for ease of use. Stick with the original plan. Sound like you are doing it right. +1 |
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Ive spliced cat5 to a 66block and it worked ok. It was a short run though. I didnt like to do it, but it was expedient. I've spliced cat5 with scotch tape and then the line was still able to be certified as CAT5 with a tester. Doesn't make it right.  Lol, right is what works. The stuff is like black magic sometimes. |
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Ive spliced cat5 to a 66block and it worked ok. It was a short run though. I didnt like to do it, but it was expedient. I've spliced cat5 with scotch tape and then the line was still able to be certified as CAT5 with a tester. Doesn't make it right. Lol, right is what works. The stuff is like black magic sometimes. The problem with the splices is they'll "work until they don't" and you don't have to touch/move/adjust them for them to start failing. Just put some noisy RF leaking device near the cable and watch your error rate go through the roof and the bandwidth go into the floor. If it must be spliced, like other posters said, do it "right" –– splice in connectors and plug them into each other, don't just twist wires together and wrap it in tape. |
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Lots of good advice here. I'd like to add... watch your AC runs and data runs. They don't play nice together. Use shielded cabling if it is in the budget. Cross AC at right angles and try to stay 2 or 3 feet away when running parallel. Don't put the patch panel near a furnace, air conditioner, or other large electric motor. Try to make the runs straight as possible, and avoid sharp edges at turns. That way you can pull off the plate in the room, and use the old cable to pull new cable if one goes bad.
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Quoted:
Lots of good advice here. I'd like to add... watch your AC runs and data runs. They don't play nice together. Use shielded cabling if it is in the budget. Cross AC at right angles and try to stay 2 or 3 feet away when running parallel. Don't put the patch panel near a furnace, air conditioner, or other large electric motor. Try to make the runs straight as possible, and avoid sharp edges at turns. That way you can pull off the plate in the room, and use the old cable to pull new cable if one goes bad. If you are going to use shielded cable you need to also use shielded jacks and shielded plugs.... |