Stranded Cable for Patch Cords? 2

[jimatkci]

Daron, (or anyone)

You commented on another message that you use solid cable in the wall, and stranded for patch cables... Why? You seem to know the standards, is this a standards issue?

I try not to make patch cables if possible, but I have a good crimp tool, and seem to make a better connection with the solid core.

I'm new to the forum, so you may have discussed this before.

 

[AvayaNovice]

Hey,

You can crimp solid or stranded cable -- but you must use ends that are designed for the cable you're crimping (ie. stranded end for stranded cable). They work better when you use the right ones

As far as using solid cable in the wall and stranded on patch cables...

I'm sure there's a better reason for it than this, but stranded cable is more flexible, so it's easier to use when you're moving it around for patching into different ports and what not.

 

[rpearson]

Stranded cable is not used in horizontal cabling because of its Attenuation(Loss of signal down the line).It is used in patching due to its flexibilty,but contributes about 20% of the Attenuation on that link.

 

[AvayaNovice]

Good point, knew it had to be something. Star for you.

 

[daronwilson]

Geez that will teach me for not checking the forum. Indeed you are correct, the stranded cable has much more attenuation per foot than the solid, hence the main reason you don't want to run it far for a link.

If you are making patch cables, you really should be using stranded. I've made plenty of the solid ones two when I needed them, before I carried a roll of stranded. The good quality crimp tool is half the battle, you also need practice since this can be a bit tricky AND you need good quality modular plugs designed for the cable you are using. Personally I prefer the AMP brand of plug and crimper, however the construction is slightly different on the modular plug, so you can't crimp it right with another crimp tool. There are many other good quality ones on the market.

I usually carry plastic boots in the box as well. I hate them when they are on a patch cable, it just makes unplugging them harder, but it does yield a better looking patch cable than without them.

Oh yeah, it is a standards issue You won't pass attenuation with 300 feet of stranded, hence it won't meet the standard, and it probably won't work.

Hope that helps, good answers all around.

Good Luck!

It is only my opinion, based on my experience and education...I am always willing to learn, educate me!
Daron J. Wilson, RCDD
daron.wilson@lhmorris.com

 

[jimatkci]

The only problem with those boots is when you are plugging the patch cord into a close area. Like a switch. Several vendors (like Cisco) will recommend you not use boots, or pull them back. The ports are so close on a switch that the boots put pressure on the switch ports.

I guess I've just done so much solid core crimping, I just feel more comfortable with it. I guess I can get another bag of stranded tips and get comfortable with them.

I was reading some of the other threads, and there was one discussing the HP -vs- Fluke testers. I have the MicroTest PentaScanner, and love it... Now that Fluke owns it, we were able to download software updates, and a great battery utility. I've always been partial to Fluke equipment.

 

[copperfiberguru]

One aspect that has not been addressed specifically...cable bend radius!

The ANSI/TIA/EIA-568-B.1 Addendum 1 Minimum 4-pair UTP and 4-pair ScTP Patch Cable Bend Radius, states...

"The minimum inside bend radius, under no load conditions, for 4-pair UTP patch cable shall be 6 mm
(0.25 in). The minimum inside bend radius, under no load conditions, for 4-pair ScTP patch cable shall
be 50 mm (2.0 in)".

The ANSI/TIA/EIA-568-B.2 defines horizontal cable as follows...

4.3 Horizontal cable
4.3.1 General
Covered herein are the requirements for balanced twisted-pair cables used in horizontal cabling. The
cable shall consist of 22 AWG to 24 AWG thermoplastic insulated solid conductors that are formed
into four individually twisted-pairs and enclosed by a thermoplastic jacket. The cable shall meet all of
the mechanical requirements of ANSI/ICEA S-80-576 applicable to four-pair inside wiring cable for
plenum or general cabling within a building.

"...in horizontal cabling" and "solid conductors" being the important words here. Now, The 568-B.1 states...

10.2.1.1 Minimum horizontal cable bend radius
The minimum bend radius, under no-load conditions, for 4-pair unshielded twisted-pair (UTP) cable shall
be four times the cable diameter and the minimum bend radius of 4-pair screened twisted-pair (ScTP)
cable, under no-load conditions, shall be eight times the cable diameter.

The typical O.D. of category 5e/6 cable is approximately .24 inches. 4 times this OD gets you about a 1 inch bend radius versus the .25 inch bend radius for stranded patch cords.
So, you see there are large differences between solid and stranded conductor bend radii. If you are routing solid patch cords in standard vertical and horizontal managers, you may be exceeding that cable's bend radius. The wire management products out on the market are designed for stranded patch cords. You may think you are increasing your channel performance but you may be doing just the opposite, by increasing the Return Loss in your channel. This equates to packet loss!

Just my $.02 worth...

Doug Bond, RCDD

 

[daronwilson]

Ahh it is a relief to have someone else support my standards compliant approach, thanks! While the bend radius is of course important, it is quite likely not the reason that solid wire is required for horizontal wiring since the bend radius is less restrictive for stranded wire. Again the reason that stranded wire is likely not approved for horiontal wiring is that you can't put 300 feet of it in the wall and meet the spec, not because of bend radius be because of increased attenuation.

With regard to cable management, point well made. Solid wiring has no place in the wire management situation.

I'm not sure I agree with your statement regarding packet loss. If I read it correctly, your stance is that increasing return loss equates to packet loss. While increased return loss at some point may cause packet loss, there is substatial head room built into the design of the channel specifications. For example, a 5% increase in return loss will likely still yield a passing installation, and as such will probably not cause packet loss. Once your installation causes you to dip below the acceptable specifications for that channel, you will quite likely experience degredation of service.

It's a small detail, but the design of the system is to provide the user with a channel capable of full throughput with some headroom. You should be able to get full throughput on a 25' horizontal cable run. Also, you should be able to get full throughput on a 300' horizontal run, even though the return loss and the attenuation will be higher.

Thanks for posting quotes from the standards, glad I'm not the only one



It is only my opinion, based on my experience and education...I am always willing to learn, educate me!
Daron J. Wilson, RCDD
daron.wilson@lhmorris.com

 

[copperfiberguru]

Daron-

You're correct. I should have stated that it "may cause packet loss". Just trying to address any folks who have tested their 4-connector links to cat 5e/6 specifications after the initial install who have very little margin to begin with. They then introduce solid patch cords later on while performing many MACs. Yes, probably a small percentage but still note worthy.

I simply just do not condone users/installers field terminating their own modular patch cords. They may work for 100BaseT but when these cords somehow migrate to higher speeds channels, the quality is just not sufficient enough to guarantee performance for these higher speed applications.

OK I'll get off my soapbox now!




Doug Bond, RCDD

 

[RandyVSP]

When I can, I buy them premade, much better to me than having to buy a roll of stranded and extra plugs just for jmpers....

In a pinch tho, the solid has worked many times...saving my butt!!!!

Randy

 

[jeffmoss26]

I have had many problems terminating stranded wire to plugs, namely the wires do not stay lined up in place to go into the plugs. I don't have this problem with solid wire, and I am using plugs designed for stranded (I think)

jeff moss