Period Cat5e cabling

[Feltwell]

For those of a technical persuasion (OK, Flyfisher and MdB unless we have any others with data cabling knowledge lurking...)

I'm running some Cat5e to my BT master socket as I redecorate the kid's rooms, so that in the future I can move the router to the BT master socket for best performance, and the kids won't need to rely on wireless for laptop use in their rooms.

I have a rather handy staple gun for cables, inherited from my father-in-law's security company where it was used to secure alarm cables. It just fires metal staples - there is no protective plastic insert. Would I be correct in saying it would be a bad idea to use this on Cat5e? The staples do pinch the cable. I've used it on alarm and telephone extension cables with no problems.

Also - common sense says that it's a bad idea to run cat5e alongside power cables, but I read somewhere that it's best not to let it cross power cables either - which will be practically impossible to achieve! Is it really much of a problem? I'll be running it alongside telecom and alarm cables, but due to the minimal power flowing through those I wouldn't have thought they would cause a problem.

 

[TheForge]

In theory running parallel is not a good idea with relation to EMI, high v low voltages, data loss etc. In practical reality I doubt you'll notice any difference. As for crossing cables I wouldn't give it a second thought.

If you're really worried, or there is an appreciable problem with interference, you could always shield one of the cables with some form of insulation (fire retardant!) or put a divider between them. After all in dado trunking there is only a thin strip of plastic to separate the two types of cable.

In reality the EMR from a standard 240 v cable is only at any noticeable level within about 1/8" of the cable anyway, so any distance between the cables will negate any problems. (Although I think the 'official' guidelines for data cabling say there should be a 6 inch gap between any parallel run .

 

[MdB]

I would avoid the staple gun I think. You would muck about with the twists in the cable a bit which are quite important and my old works install had great problems due to tight radius corners so I would avoid any distortion if at all possible. I wouldn't worry about cable crossing but I would try to keep some separation on a parallel run.

 

[Flyfisher]

A lot of the guidelines associated with data cabling are based on installing a system that will meet the specified performance in the appropriate standards. Indeed, commercial installers will use quite sophisticated test equipment to certify the performance of the installation. All of which you might expect.

The good news for most domestic applications is that the relevant performance standards are based on a length of 100m, comprised of 90m of fixed (solid core) wiring and 2x 5m lengths of multicore patch cabling with associated connectors. The even better news is that there is a degree of latitude in the standards such that the performance figures will normally be achieved at somewhat greater lengths. The longest Cat5e data cable runs I've encountered were about 240m in a trading floor application and they worked fine for most things.

The performance of such cables falls off as the length increases but it is also detrimentally affected by the things being discussed here, i.e. crushed cables, kinked cables, electrical interference effects etc. However, since most domestic applications will involve far shorter runs than the design standards allow for, the effects of such things are less important than they might be in a commercially certified installation.

If I was installing cat5e for network purposes then, like MdB, I'd avoid a staple gun that pinches the cable because I'd like that cable to be able to support up to Gigabit ethernet (1000Mbps). However, if I was using it just to extend my telephone wiring then I'd be far less concerned, because even a 'compromised' length of cat5e is likely to out-perform the BT wiring anyway.

Try to keep data cabling away from mains wiring and things like big electric motors (do you have a lift at Feltwell towers? :wink: ), but I wouldn't agonise too much about short runs close together and crossing at right-angles is no problem at all.

The other thing to remember is that all these things are generally to do with perfomance, rather than failure. The communications protocols that invisibly move our data around are very clever at ensuring data is not corrupted. So, bashed-about cables in noisy electrical environments might slow things down, but things would have to be really very bad before communication breaks down completely. Also, considering that most routers 'talk' to PCs at 100Mbps but broadband speeds are considerably less, then network cabling can stand a lot of abuse before it becomes a noticeable limitation for most domestic applications.

 

[Feltwell]

Very useful indeed, thanks all. I think it's fair to say that Feltwell Towers will be running at slightly less than technology-leading speeds, so that all sounds good. One final query - can you joint Cat5e cable, perhaps in a wall box? The reason I ask is that some rooms will probably have layout changes in the future, so I'm putting in 2 RJ45 sockets in a single room. The easiest way to cable it up will be to run cable from one to the other, then on to the router. We'll never want to use both sockets at once.

do you have a lift at Feltwell towers? :wink:

Funny you should mention that, remember this recent picture?

Some mornings one of those Stannah stairlifts would be a great help, but we'd need several. Feltwell Towers is short of many things but definitely not stairs!

 

[Feltwell]

I think I've just answered my own question - leave plenty of slack in the cables, I can always pop one of these in a wall box in the future if connecting 2 cables to the same RJ45 plate outlet is a no-no. I can't see why I couldn't put 2 cables onto the same RJ45 plate outlet, although the connections are the punch-down type rather than screwed.

http://www.ebay.co.uk/itm/Cat5e-Inl...rkingTools_Accessories_SM&hash=item3f091029d8

 

[MdB]

Reflections....

If you have a long piece of cable with a computer at one end and a router at the other then there won't be any problem with having an extra unused connection in the middle. However, if the computer was moved from the end of the cable to the middle, you will have a section of cable acting as a spur with nothing on the end of it. Signals will travel down the cable, hit the end and reflect off and travel back down the cable to the computer causing mayhem with the original signal. So no, don't do this.

Either run two cables or arrange the single cable somehow so that you can move the end in the future.

 

[Flyfisher]

The best way to create a flexible cabling system is to create a 'star' with a central 'hub' and then use short RJ45 patch leads at the 'hub' end to make whatever connections you want. If the BT master socket is also near the 'hub' then you can also easily patch the telephone line to any outlet in the house.

There's no need to install all the cabling at the same time but if you have a general plan about where the 'hub' will be then it can be installed gradually, but always bringing the cable back to the 'hub'.

Below is a 'hub' I installed in a previous house. This was in a converted attic space that I also used as a test lab at the time. All the Cat5e cables from around the house led back to the various quad RJ45 outlet boxes you can see in the photo. There's also an ISDN line (it's an old photo) plus the router and network switches, making it very easy to quickly patch together whatever network configuration was needed. It's a little bit messy, I would agree, and a neater installtion would have everything contained within a small 'comms cabinet', but the principle is exactly the same.

Not only does this give you maximum flexibility for future changes within the house but is also avoids the problem MdB rightly mentioned about reflections caused by lengths of connected cables that are not connected to anything.

But if you don't fancy a 'hub' approach, there would be nothing wrong with installing a dual RJ45 outlet and then using a short RJ45 jumper cable to join the outlets together as part of making a cable run to another location. Just be sure that both ends of a cable run are connected to pieces of suitable equipment. This will ensure that the cables are correctly terminated to eliminate the reflections problem that MdB mentioned.

 

[Feltwell]

Thanks Guys - very useful, I had no idea of the "reflections" problem. I've just gone to Screwfix to buy more cable, rather glad I bought 100m rather than 50m now!

The BT Master socket is in our bedroom, so not an ideal place to put a comms cabinet or loads of exposed wiring for a patch panel. However, telephone extensions are already in place and the wiring nicely hidden, so this is only for data.

What I was thinking was a quad-RJ45 socket outlet near the BT master socket, which our 4-way router can then plug into with patch leads - this is all hidden down the side of a chest of drawers. RJ45 sockets in each bedroom, with cables running directly back to the quad socket. Where I've got more than one socket in a room, perhaps I'll run a cable back from the "spare" socket and just leave it under the floorboards below my quad socket, labelled up - for future use if required - and put a blanking plate at the room end, with the cable coiled up behind. Or I could put a second quad socket in and only connect up what I want to, which is I suppose effectively a hub.

I can see the logic of using a short jumper lead in a dual outlet and just running 1 cable to each room, but if that outlet is visible it will look a bit odd.

 

[MdB]

What I was thinking was a quad-RJ45 socket outlet near the BT master socket, .

A quad socket is so limiting. Just fit one of these and then you will have room for expansion...

 

[Flyfisher]

. . . which would fit nicely into a standard comms cabinet, together with the router and other network gubbins. :lol:

I'm still working on our network cabling, but it's coming along slowly . . .

 

[Pford75]

Netgear???!!!!??? :evil:

I wouldn't settle for anything less than a CRS 3 - 322 Tbps

http://www.cisco.com/en/US/products/ps5763/index.html

 

[Feltwell]

Server room? That's not a server room - that's an explosion at the factory that makes silly string.

 

[worms]

Server room? That's not a server room - that's an explosion at the factory that makes silly string.

Ok, I've got to ask... Is there a reason why there would be a packet of salt on the table in the picture? Has it some obvious techno-function that us lesser mortals would not know about, or is it an in-joke, that again would be beyond most of us? Or just random?

 

[TheForge]

Absorbing moisture like a rudimentary dehumidifier!!

 

[worms]

Absorbing moisture like a rudimentary dehumidifier!!

Instead of a sack of dried peas?

 

[MdB]

You use salt when storing computer passwords. The addition of salt makes it harder to use rainbow tables to recover encrypted passwords when your server gets hacked.

(and I haven't made any of the above up!)

 

[LadyArowana]

You use salt when storing computer passwords. The addition of salt makes it harder to use rainbow tables to recover encrypted passwords when your server gets hacked.

(and I haven't made any of the above up!)

:shock:

 

[Keithj]

He speaks truth about the salt, but that doesn't help with your cable run.

Agree: avoid the staple gun.

Agree: not too close to mains cables, but if you have decent "twisted pair" Cat 5 cable it won't be critical.

Agree: avoid spurs. Standing waves do wacky things (spoken by the man who learned the hard way).

 

[Feltwell]

OK, someone's got to be daft enough to ask so it might as well be me - Salt? Passwords? Please explain, preferably in English!

Cables are all in, I never want to see another Cat5e cable again, about 130m all in. It's amazing how much you can use in a house that isn't really that large. And Screwfix, please, tell your supplier to put the cable on a drum - 100m of cable just looped and held together with stretchwrap with no drum is a right pain in the @rse to use.........

And for anyone who has got any cabling jobs to do, data, co-ax, telecoms or power, I heartily recommend you invest in a set of cable rods - they make life SO much easier when threading cables around under floors.

http://www.toolstation.com/shop/p75799