Suggestions for good plenum grade cat 5e cable

[Spork Schivago]

Hello,

Does anyone have any suggestions for a good brand name for plenum grade cat 5e cable, in the colour red? Looking for around 1,000 feet. I've seen some that say 200MHz, 350MHz, maybe even 100MHz and 250MHz (but I can't seem to find them on the first page of Amazon). I've tried searching what the frequencies mean, and one guy says it's just a sales gimmick. They just tested it with 350MHz frequency. He says he has speaker wire and can test it up to 1,000MHz and it doesn't mean squat.

Another guy says the higher the frequency, the tighter the wraps (I think he's talking about the grounding wire for each pair being more tightly wrapped). This other guy claims that the higher the frequency, the less susceptible to EMI.

Is that true? We're going to be using the red cat 5e plenum grade stuff for telephone. I had ran cat 3 in just the baby's bedroom, but I'm going to remove that now and run the cat 5e, after I buy it. Just want to make sure I do it right and buy the right stuff.

Thanks!

[diif]

Re: Suggestions for good plenum grade cat 5e cable

I've never heard frequencies mentioned in regards to cat5/5e/6 cable.
I have two boxes here, one interior, one exterior, neither have frequency marked on them.
There is no grounding wire in cat5/5e/6 cable. What he's talking about is the twists in each pair being tighter. They will use more copper and therefore be more expensive.

[Uniballer]

Re: Suggestions for good plenum grade cat 5e cable

I like Belden 1585A cable just fine. The price, not so much.

I have used many brands and they generally all work fine (I had some Southwire cat5e cable that sucked to work with because of the insulation, but once installed it worked just as well as all the others). Beware of CCA (copper coated aluminum) cables: AFAIK these do not really meet the required specifications.

Gigabit ethernet uses frequencies up to about 125 MHz, so you really don't need 350 MHz cable.

FYI - ethernet uses isolated differential (balanced) transmission (that's what the little transformers in all the devices are for). So there is no ground wire unless you have shielded cable. There could be a fixed relationship to ground potential if you are using Power over Ethernet (PoE).

[srhofmann]

Re: Suggestions for good plenum grade cat 5e cable

Go with a name brand cable that actually has some specs published. There's more to ethernet cable than just the just the pairs of wires. The number of twists per inch, the skew between pairs and overall attenuation are usually the most critical factors in how well a cable performs. If there aren't any real specs available for the cable avoid it.

Belden 1585A is good choice, it's been around a while. I'm in the process of redoing a lot of the wiring in my house and I'm using 1872A. It's a bitch to work with but I got it for 10 cents a foot.

Here's a couple of data sheets so you can see the difference in cable specs.

[Spork Schivago]

Re: Suggestions for good plenum grade cat 5e cable

I've never heard frequencies mentioned in regards to cat5/5e/6 cable.
I have two boxes here, one interior, one exterior, neither have frequency marked on them.
There is no grounding wire in cat5/5e/6 cable. What he's talking about is the twists in each pair being tighter. They will use more copper and therefore be more expensive.

That's what I was talking about when I said grounding wire. I thought there were four pairs of wire and each pair had one of the wires that was ground and it was twisted around the other wire to prevent interference. But after reading your message, it seems I was wrong with them being ground wires.

I've uploaded a picture. Pins 4, 5, 7, and 8 don't actually have signals going through them, right? Those are the ones they use to twist around pins 1, 2, 3 and 6, right? If they're not grounded, how do they prevent the interference? Thanks!

[Spork Schivago]

Re: Suggestions for good plenum grade cat 5e cable

I like Belden 1585A cable just fine. The price, not so much.

I have used many brands and they generally all work fine (I had some Southwire cat5e cable that sucked to work with because of the insulation, but once installed it worked just as well as all the others). Beware of CCA (copper coated aluminum) cables: AFAIK these do not really meet the required specifications.

Gigabit ethernet uses frequencies up to about 125 MHz, so you really don't need 350 MHz cable.

FYI - ethernet uses isolated differential (balanced) transmission (that's what the little transformers in all the devices are for). So there is no ground wire unless you have shielded cable. There could be a fixed relationship to ground potential if you are using Power over Ethernet (PoE).

Thanks. I should mention that this cat5e is going to be used for the telephone. I've already ran the cat6 for the ethernet in her bedroom. For telephone, do you think it'd be okay to go with the cheaper wire? I've tried very hard not to run the wires near the AC electrical wires, but down stairs, it's a mess! Someone just ran the wires any which way. I might have to use conduit in the future down there or something. It's a bit hard trying not to cross over one of the electrical wires.

[Spork Schivago]

Re: Suggestions for good plenum grade cat 5e cable

Go with a name brand cable that actually has some specs published. There's more to ethernet cable than just the just the pairs of wires. The number of twists per inch, the skew between pairs and overall attenuation are usually the most critical factors in how well a cable performs. If there aren't any real specs available for the cable avoid it.

Belden 1585A is good choice, it's been around a while. I'm in the process of redoing a lot of the wiring in my house and I'm using 1872A. It's a bitch to work with but I got it for 10 cents a foot.

Here's a couple of data sheets so you can see the difference in cable specs.

Man, that 1585A is very pricey just for telephone wire. I want to go for it, because it looks amazing, but I don't think we can pay that much. We're going to need more than 1,000 foot. Right now, 1,000 foot will handle her bedroom and give us a little extra. But with at least 2 wallplates per room (maybe 3 or 4 in some rooms), we're going to have 6 to 7 rooms that need the wallplates. 3 of them are upstairs. That's a lot of money at around 399$ per 1,000 foot! I found a place that's supposedly selling it for 294.32$ per 1,000 foot, free shipping, but it's still a bit too pricey for us.

[srhofmann]

Re: Suggestions for good plenum grade cat 5e cable

If it just plain old fashioned telephone, not voip, literally any kind of wire will work. It only needs to have a bandwidth of 10Khz, not megahertz rated cable. Doesn't even need to be twisted pair. Bell wire would work fine......

It's not a signal and ground in a pair, it's a differential pair. One wire is driven high while the other wire is driven low. It's a coupled pair. The wires are twisted around each other so if any interference is induced in one wire it will also be induced in the other wire. But since it's a differential pair the noise won't be as noticeable.

[Spork Schivago]

Re: Suggestions for good plenum grade cat 5e cable

Okay, thank you Srhofmann. It wasn't too long ago that I learned how differential signaling worked. So that means all 8-wires are being used, when being used for 100Mbps ethernet...I wonder why the pictures I found showed pins 4, 5, 7, and 8 as being N/C.

I found this:

It's a datasheet for plenum rated cat5e cable, in red. The price is within our range, and from comparing it with the Belden datasheet, a lot of the numbers match. There's a few that don't though. For instance, in the Vertical Cable's datasheet, I see:

Mutual Capacitance (nF/100m Max)  5.6

But in the Belden datasheet (for the Plenum rated cable), I see:

Nom. Mutual Capacitance:
Capacitance (pF/m)
49.215

Now, the Belden one says Nominal Mutual Capacitance and the Vertical Cable just says Mutual Capacitance, so maybe that's why the numbers are so different....could someone a little more familiar with the specs maybe just glance over the Vertical Cable one and tell me if they think it's a good buy? 144.99$ + 11.40$ shipping per 1,000 feet, which is much closer to our price range. If we ever decide to switch to something like VoIP, perhaps this wire would be a good choice and we wouldn't need to replace it? Trying to think a head here a bit, you know?

[Uniballer]

Re: Suggestions for good plenum grade cat 5e cable

Okay, thank you Srhofmann. It wasn't too long ago that I learned how differential signaling worked. So that means all 8-wires are being used, when being used for 100Mbps ethernet...I wonder why the pictures I found showed pins 4, 5, 7, and 8 as being N/C.

Only 2 pairs are used for 100-Base-TX (100Mbps). All 4 pairs are used for 1000-Base-T (gigabit), and for 100Mbps with POE. Install all 4 pairs using the appropriate standard EIA/TIA-568A or 568B (your choice, but one building should only be wired one way).

I found this:

If you do a good job installing it then that cable will work great for everything up to gigabit ethernet.

It's a datasheet for plenum rated cat5e cable, in red. The price is within our range, and from comparing it with the Belden datasheet, a lot of the numbers match. There's a few that don't though. For instance, in the Vertical Cable's datasheet, I see:

Mutual Capacitance (nF/100m Max)  5.6

But in the Belden datasheet (for the Plenum rated cable), I see:

Nom. Mutual Capacitance:
Capacitance (pF/m)
49.215

Now, the Belden one says Nominal Mutual Capacitance and the Vertical Cable just says Mutual Capacitance, so maybe that's why the numbers are so different....could someone a little more familiar with the specs maybe just glance over the Vertical Cable one and tell me if they think it's a good buy? 144.99$ + 11.40$ shipping per 1,000 feet, which is much closer to our price range. If we ever decide to switch to something like VoIP, perhaps this wire would be a good choice and we wouldn't need to replace it? Trying to think a head here a bit, you know?

49.125 pF/m would be 4.9125 nF/100m (there are 1000 pF per nF). So they are not all that far off.

[srhofmann]

Re: Suggestions for good plenum grade cat 5e cable

I just have to ask why? You said that you were going to use this for telephone service why spend the money? It's overkill! For decades POTS service was delivered using unshielded, untwisted pairs. If you've already got Cat 3 installed it should be fine.....

[Spork Schivago]

Re: Suggestions for good plenum grade cat 5e cable

Only 2 pairs are used for 100-Base-TX (100Mbps). All 4 pairs are used for 1000-Base-T (gigabit), and for 100Mbps with POE. Install all 4 pairs using the appropriate standard EIA/TIA-568A or 568B (your choice, but one building should only be wired one way).

Are you sure the other wires aren't being used? I don't necessarily mean for data. I'm trying to understand how they prevent interference and if differential signaling is being used, it'd make sense to me, but that would mean those wires are being used, right? If they're not being used at all....how do they prevent interference, with 100-base-TX?

If you do a good job installing it then that cable will work great for everything up to gigabit ethernet.

We are running CAT6 for the gigabit stuff, but it's good to know that this Vertical Cable, if installed properly, will be able to handle other stuff, just in case in the future, we decide we want to use it for something else, or we sell the house. I really want to keep the Plenum grade stuff red, so I know it's fire resistant. But I'm also thinking gigabit ethernet will be blue (because that's the colour we already have) and telephone stuff will be read, so I can more easily identify if it's for the phone or the ethernet.

49.125 pF/m would be 4.9125 nF/100m (there are 1000 pF per nF). So they are not all that far off.

Doh! One's listed as per meter, one's listed as per 100 meter! That's where I was getting confused. I did the conversion and I thought the numbers were:
49.125 pF/100m for the Beldin and 5600 pF/100m for the Vertical Cable!

So the Beldin is 49.125 pF/m. That would make the Vertical Cable 56 pF/m. That's much closer. Thanks!

[Spork Schivago]

Re: Suggestions for good plenum grade cat 5e cable

Uniballer, nevermind, I think I see where I was going wrong. Differential signaling is used, but only on the two pairs, for 100-base-TX. We use T568B in this house. So, white orange and orange will carry a differential signal, then white green and green will carry a differential signal. Blue and white blue won't be used, and brown and white brown won't be used. At least with 100-base-TX.

We try to be extra careful with crimping the ends on. My wife does the crimping because my eyes aren't what they used to be, and if I remember correctly, that's where most of the cross-talk comes from. But for this application, there shouldn't be any crimping, just some punch downing.

[Uniballer]

Re: Suggestions for good plenum grade cat 5e cable

Are you sure the other wires aren't being used? I don't necessarily mean for data. I'm trying to understand how they prevent interference and if differential signaling is being used, it'd make sense to me, but that would mean those wires are being used, right? If they're not being used at all....how do they prevent interference, with 100-base-TX?

10 and 100 Mbps ethernet over twisted pair only use two differential pairs: one pair for transmit and one pair for receive. Some early installations used the other pairs for telephone signals, or a second ethernet connection, but this was deprecated a long time ago. Gigabit ethernet uses all 4 pairs for signaling. PoE can be carried on the pairs that 10 and 100 Mbps do not use, but on gigabit the power can be on any/all of the pairs carrying signal.

EDIT: sorry, I didn't see your reply before typing this.

[Spork Schivago]

Re: Suggestions for good plenum grade cat 5e cable

I just have to ask why? You said that you were going to use this for telephone service why spend the money? It's overkill! For decades POTS service was delivered using unshielded, untwisted pairs. If you've already got Cat 3 installed it should be fine.....

The cat3 isn't up to code. When we bought the house, all the old wiring was no good. Even the coax needs to be replaced. They used cell phones and they got a hodgepodge of different telephone wires throughout the house. We're standardizing it, getting a media enclosure for it, etc. We're adding ethernet and new coax to each room, so we figure why not add an RJ-11 port to each wallplate as well?

When I bought the cat3, I thought that was how it was done. I can use it, but the wall plate RJ-11 ports, they're designed for cat5e. The stuff for the media enclosure is designed for cat5e. I ran just two cat3 wires. Than we had work done where we paid a company to come in and do some fancy stuff. They replaced the furnace, they added a cold-air return upstairs.

The cat3 runs through the cold-air return. That's definitely not allowed. It needs to be Plenum grade if it's going through a cold-air return, at least in this area. So, before I do the rest of the house, I figured why not just do it right? Remove the two runs of cat3 I ran and replace it with Plenum grade cat5? It shouldn't be too hard. I'm hoping I can just connect the cat5e to the cat3 and just pull it through....

We've already ran out of cat3, so we have to buy new wire anyway, for the rest of the rooms. And instead of buying more cat3, I'm just going to do it proper and use the cat5e for the telephone.