Cableing stranded vs solid vs age

[Nuwave]

Anyone know of any good articles or documents explaining how a copper cable over time gets hard and brittle?

 

[imagoon]

Not sure what your getting at, considering I have old data cables from the late 70's (thick net go!) that is fine. The copper wire in my friends house that was built in 1860s is fine (in the copper sense) the cloth coating is falling off though. The plastic covering can get old and brittle but that typically stems from the flexing agent in the insulator "drying out" over many years or exposure to heat which accelerates the process.

Copper (copper wire types) itself is pretty stable in a "normal" environment like a home or office.

 

[Nuwave]

I guess i'm kinda assuming that the older the metal is the more resistant it is to bending. Are you saying that is not true at any degree?

Also can the insulation of the wire get brittle enough that when you try to bend a cable after 20 years that it may cause damage to a solid core wire?

I work in a large corporate environment and one of the policies is that we do not pull back data cables from location A and put them in Location B. There is lots of rational behind it but one of the reasons I'm trying to find out more information on is that the metal of the data cable could loose some integrity when pulling out the cable.

Any insight is appreciated and thanks for your responce imagoon.

 

[spidey07]

You're most likely exceeding the bend radius and twisting/kinking it when you yank it out. Nobody in their right mind would reuse cabling like that.

Cable is extremely cheap.

 

[ScottMac]

Any bending of a solid core able will weaken it and risks kinking it ... which drives it out of spec. One to-tight twist of the cable, one kink, one stretch beyond the proper pulling tension, one excessive bend radius, and the cable no longer meets specification (i.e., requires a new certification scan, but by the book is automatically out-of-spec).

Exposed copper can oxidize, insulated copper generally doesn't age unless water and other contaminants get into the cable and in-contact with the metal directly. COnnectors / punch downs / connection to non-copper terminals are a different story.

 

[Nuwave]

Originally posted by: spidey07
Cable is extremely cheap.

Ahh, you cought me more explanition is necessary, the cabinet the new data runs would run to is 100% full. The cost of upgrading the cabinet to a bigger one is rather substantial.

Thanks for the responces.

 

[imagoon]

Originally posted by: Nuwave
I guess i'm kinda assuming that the older the metal is the more resistant it is to bending. Are you saying that is not true at any degree?

Also can the insulation of the wire get brittle enough that when you try to bend a cable after 20 years that it may cause damage to a solid core wire?

I work in a large corporate environment and one of the policies is that we do not pull back data cables from location A and put them in Location B. There is lots of rational behind it but one of the reasons I'm trying to find out more information on is that the metal of the data cable could loose some integrity when pulling out the cable.

Any insight is appreciated and thanks for your responce imagoon.

Policies like that can be multifold. What spidey mentioned is the #1 reason. Pulling out a cable incorrectly can damage it and others near it. In critical environments it can make sense to toss the cable (or at least put it in the 'workstation' bin.)

In most cases, the copper itself is "ok" even if the insulation has started to dry rot, but the exposed copper will tend to oxidize over time (read long time in a typical homo/office). However, most of that is moot because bad insulation = trash bin cable as far as I am concerned.

 

[Nuwave]

Yea I'm very aware of the rational of why not to do it. A colleague mentioned that one of the reasons why not to do it was because old cable can become brittle. Moving it could cause damage - put aside the fact of what spidey had mentioned about kinks & bend radius.

You and Scott really answered the question saying that it doesn't happen unless there are some extenuating circumstances.