CAT5 Woes. Are cat5e and cat6 cross compatibl

October 19, 2009 at 15:39:07
Specs: Windows XP
Yay, networking, my favorite...

Ok, so I'm helping a school that is in really bad shape. Their enrollment is WAY down, and they're trying to improve their technology.

On to more...

Their current building is fairly large, your basic parochial school, about 30 yrs old, concrete block walls, drop ceiling...

The cat5 network was put in about 9 years ago in 2000.

It was put in by parent volunteers who probably didn't know what they were doing, and didn't know what code restrictions were. They pulled wire wherever they wanted to, not hanging it or securing it to anything. Plus, they crossed a lot of electrical and other building wiring, which should NEVER be done.

Everything was just perfect until this year when we tried to deploy a backup system. Well, in some parts of the building, the backups would just zip by, and others, it would take DAYS! Generally, the size of the backups were about the same. (They're incrementals, just in case that mattered)

Lo and Behold, the speeds of the network vary. Some computers are getting the full 100 MBPS, while others were getting 10, and others getting anywhere in between. One even got 2. (BTW: this is all local network, we're not getting in to internet.)

I suspect this is because of electrical wiring interference??

And, when the school went to conduct a fire drill, a pull station was pulled, and NOTHING happened. Thank God this was a drill.

Once again, Lo and Behold, it was network interference. Turn the switches off, the pull station works just fine. Turn it back on, it doesn't. This is a serious safety issue.

We are also thinking that the volunteers didn't pay any attention to the 100 Meter cat5 rule. Sigh...

Also, they didn't leave enough slack in the wire to strap it to the roof beams, so in order to get it off the rest of the wiring, its all going to have to be rerun. Yay once again, considering I'm gonna get to do it! (**ahem**sarcasm**ahem**)

Have you ever heard of Cat5 causing so many issues before?

So, when we rerun the wire, we'll probably run cat5e to all the drops. That way, we'll have better speed and be able to run it further.

One question: If we were to futureproof ourselves and run cat6 drops to each classroom, could we plug in all our existing cat5/cat5e patch cables to the computers?? Or would we need to make all new cat6 patch cables??

Thanks in advance,

See More: CAT5 Woes. Are cat5e and cat6 cross compatibl

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October 19, 2009 at 15:47:17
It makes sense if rewiring the core to do it in cat6. Using cat5 patch cables make no difference unless you are trying for gigabit speed then you need cat5e or 6.

Alarm panel should be going to the fire panel not any network switches.

You need to think about the runs but also about power. Correcting one without the other will only result in this being done again but power wise instead of cable wise. After all you want something at the other end of the cable right? It has to have power.

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October 19, 2009 at 15:54:43
I assume by alarm panel you mean alarms??

They do go to the fire panel, but the cat5 in the ceiling is interfering with the fire wiring...

And the power is just fine, they actually attached it to the ceiling beams unlike the cat5, which they ran wherever they felt like.

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October 19, 2009 at 16:11:20
"but the cat5 in the ceiling is interfering with the fire wiring..."

Doesn't work like that if you mean in interferance like in EMF.
There should be no connection between network wiring and firepanel wiring.

You are also missing my point about electrical. If may be fine in that they are "hung off the ceiling beams" [that is a scary picture and its one not even close to code] but is it sufficent?

For example is the power to a room power all the room including lights? Or multiple rooms and lights? Classrooms today have a minimum of two power circuits [20amp] and they are separate from lighting circuits [15amp].

What happens, similiar to your cat5 wiring, is you have folks "extend circuits" without the understanding of loads to be placed on those circuits.

I was in the building trades for 17 years [and still am since I completed a 16month remodel of a backyard cottage with building permits and did all the work myself including power, water, sewer. I put in the bathroom and kitchen single handedly. I had a plumber help with the sewer and had to hire an electrician because the unit was to be a rental the work has to be vouched for by a licensed electrician]. Now computers for 17 years. Think I am ready for a third career :-)

Having said that I can assure you that you have more issues than cat5 wiring and alarm panels that don't work. This is all indictive of management that doesn't understand building needs.

Question is how deep do you want to go to correct this?
By law you must have a low level electricial contractor do the work under a permit [its a school]. Not doing so, and someone gets hurt or dies, you go to prison.

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October 19, 2009 at 16:18:47
Yes, and by "attached to the ceiling" I meant by conduit. Its not bare wire.

Half of the class outlets are powered by one 20 amp and the other by another 20 amp. I'm not sure about the lights, but they're not on the same circuit. All of our wiring is 12 gauge though.

And, once again, the electrical is fine. All the metal boxes are grounded, everything's in conduit...etc.

According to our city's regulations, we don't need a licensed anyone to do network and phone wiring, but it has to be "out of harms way" and not just laying around on top of the drop ceiling like it is now. The people that put it in did not secure it "out of harms way" and therefore it needs to be rewired because they didn't leave enough slack to be able to attach it to the real ceiling.

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October 19, 2009 at 17:10:14
"didn't pay any attention to the 100 Meter cat5 rule."
"That way, we'll have better speed and be able to run it further."

The rule applies to ALL ethernet runs. You would not want to exceed 328ft/100m cable runs.

Which brings me to planning the topology.

Where is the demark? [its where phone/data come into the building]
Distance from demark to farthest classroom [adding the extra to go to the ceiling and transverse the ceiling and back down again?
It there a closet or area central to all that can be used as the central location?

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October 19, 2009 at 17:25:06
Our demark is in our electrical room. The internet and phone comes in there. But then, it is ran about ~200 feet to the computer lab. There, it is connected to the gateway (not sure what/where it is right now, the rack is a mess). Then, its switched off to individual drops in each room. The computer lab is pretty central, but it is going to be moved soon. But still, all the networking equipment will be staying in the central room. I'm not sure the exact length to the furthest, but I'd say somewhere around ~400 feet (to the gym).

And I thought that cat5 could go 100M, cat5e could go 350M and cat6 could go 800ish M. I guess I read wrong wherever I read it...But it said that because cat5e/6 used bigger gauge wire, it could run longer, similar to electricity.

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October 19, 2009 at 19:48:14
Yep cable lenght is a static constant.
I think you were looking at mHz rates.
cat6= 250mhz
cat5= 100mhz

You can read this about the 350mhz debacle

Looks like you are OK from demark to central office [computer lab]. Might want to consider framing in some walls to provide server/network equipment security. You sure don't want the students having access :-(

You would want to go with a rack mount wiring harness/patch panel ports since you already have some rack mounted equipment. These are cool in that you punch down the wire in the back and the face is all the patch ports. Make sure to document each run on the cable and the patch.

You may need a intermediate point between the gym and the central office unless from central to gym its less than 328ft [I never press that limit btw]. Just enough to power a switch. I have seen things like this just parked up in the ceiling.

you might want to consider some channel hardware so you can route your wiring around and away from all EMF sources. Makes it easy to just drop the cable in and not have to bundle it. I have even made my own out of pvc pipe and a double blade channel down the lenght to drop the cable into.

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October 19, 2009 at 20:30:45
We already have 1 24 port patch panel, but all the other
cables were done crappily and just had the male plugs
crimped on to them. But I personally like the keystone patch panels because I think theyre easier to install.

As far as the channels, I was thinking about just using big
hooks, but I like the idea of the pvc tray. What size pvc did

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October 20, 2009 at 06:28:46
3" to 4" pvc. Used pan head screws thru one side to screw into wood or two pre drilled holes and heavy duty cable ties to pipes.

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October 20, 2009 at 07:48:13
Looks like you are OK from demark to central office [computer lab]. Might want to consider framing in some walls to provide server/network equipment security. You sure don't want the students having access :-(

Alternatively, APC makes a nice wall mounted locking rack that can hold either network appliances or if need be (although I don't recommend it) a rack mount server. We used one in a temporary location and I cabled it. It had two 48 port patch panels and then two 48 port switches in it. All in all, it was clean and neat and the lock kept unwanted people out.

I've pulled more cable than I care to think about through ceiling spaces without the benefit of conduit. As a rule of thumb you want to keep it bundled neatly and off of lights and electrical and any other source of emi. However, you don't have to spend a lot of $$$ to do a neat, tidy, safe job of it. We mostly use plastic tie straps and occasionally a bit of electrical tape.

The point is, if it's up in a ceiling space, it won't be seen after your finished and the ceiling is closed. So save yourself some money buy a big bag of tie straps and a couple rolls of electrical tape.

I would recommend using Cat5e cable instead of 6 unless you can find a real good deal on Cat6. It has been coming down in price quite a bit but it is normally noticeably more expensive than 5e.

But I personally like the keystone patch panels because I think theyre easier to install.

I like them better too but wouldn't say their easier. However, they are neater. Instead of a cable with an RJ-45 on it dangling out of the wall, you have a nice neat faceplate with one (or two, or even three) each of Data (RJ-45) and Phone(RJ-11). I'm pretty fussy about the work I do and insist it be done correctly and neatly.

Do not forget, when you're finished pulling and punching everything, you will need to test/certify the cables. Do NOT use a blinking light tester, they're crap. If you don't own a tester that's capable of testing and certifying, then you can hire someone who does own one to come and do it for you. Most any electrical contractor will have the tool you need. There are also specialist network cable companies who will as well. I highly recommend calling around and getting quotes before deciding on whom to hire.

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