[Tfug] Cabling uvugy3y9

[Bexley Hall]

Hi Kramer,

On 1/18/2014 1:30 PM, Kramer Lee wrote:
> I would not be surprised to find out that the basic design of the
> network plastic connector is optimized to keep people buying as many
> cables as possible because that little retention clip breaks off so

Well, as cynical as I am :> I still suspect the real reason is they
opted for "inexpensive" instead of "reliable".  Consider telco cables...
how often do you insert/remove those connectors?  It seems like it
may have been reasonable to expect the same sort of usage patterns
from network cables "way back when"...

> easily when there is no protective plastic hood on it, and it will
> break eventually even if it does have a protective hood.  When the
> retention clip breaks off most people are just going to buy another
> one.

Yup.

> I saw RFI from having the network cables close to power cables
> discussed in this thread.  Was there a problem confirmed to have been
> caused from that?  Did it involve long stretches of cabling, or power
> lines connected to sockets which were incorrectly wired?
	
The NEC requires 50mm between power and communication cables.  Skin
resistance can drop to as low as ~1K ohm when "wet" (perspiration)
meaning even things like PoE can deliver a "noticeable sting".
(10mA will paralyze muscle -- 100mA will send the heart into V.fib
while 200mA will cause it to seize up... both are high probability
of death scenarios)

How much of a pedant you choose to be depends on how much you
value signal integrity of those cables.  Signals can couple between
cables directly (a galvanic short), capacitively or inductively.

E.g., locating telephone and datacom cables adjacent to each other
can be just as bad as locating datacom by a power conductor.
(phones that "ring" can couple to the datacom cable creating a
momentary bit of "noise" on that line).

Similarly, audio cables can have potentials approaching that of
the AC mains.

Bottom line, just because its "low voltage" (whatever that means to
you) doesn't mean it can be treated like *string*!  I.e., it's not
allowed to fasten cables to lengths of conduit, fire control (sprinkler)
pipe, above dropped ceilings, in cable trays alongside power, etc.