Re: what is the best wire for a perimeter alarm

["Roland More" <NoSpamroland@xxxxxxxxxxxx>]

Here is a case where a little knowledge becomes dangerous. Someone reading
your post might get the idea that running shielded wire is always *best*,
and alarm companies don't do it simply for pricing reasons. That is simply
not true. Your belief that shielded wire helps with lightning induced
problems doesn't prove true in real life either in most cases.
Trading RF problems for wire capacitance issues is not a good trade. You
might not even know such wire capacitance problems can exist, or how they
might manifest themselves. Using shielded wire when it is otherwise not
called for can be an extremely risky business, especially mixed in with an
out of spec gauge of wire. Occasionally problems with RF occur that running
shielded only makes worse, especially on any analog data loop. A few panel
manufacturers ban its use outright, especially some fire panel
manufacturers. Then again some few manufacturers insist on using shielded
wire, typically only on the data runs. Running shielded wire can DECREASE
the total allowable run distance by up to half on many data loop type
systems (yes that technology is used in residential type systems). Other
systems have a very heavy spec on the allowable wire capacitance (especially
fire systems using an analog addressable schema). Too much capacitance in a
wire, especially shielded, can bring it own set of unique and vexing issues
to have to trouble shoot.  And before you ask, yes there definitely is a
capacitance spec on wire and many panel manufacturers make use of that spec.
In other words, follow the wiring recommendations of any panel manufacturer
carefully. If you plan to deviate from the recommendations, then consult the
panel manufacturer about any type wire you plan to run that is in any way
different.

"Bill" <bill190nospam@xxxxxxxxx> wrote in message
news:5l2gisF65907U1@xxxxxxxxxxxxxxxxxxxxx
> If you want the *best* wire... In addition to what others said, note that
> all that wiring running in the walls/attic of a house acts as a big
> "antenna".
>
> The wiring can get voltage running in it induced by nearby radio
> transmitters, etc. and lightning strikes - causing false alarms sometimes.
>
> If you use "shielded" wire and ground one end of the shield (at the main
> box), this will keep the outside electrical interference out of the
> wiring.
>
> Shielded wire is like TV coax wire which has a metal wrap inside the
> jacket. But you can get regular 2, 4, [or whatever] conductor shielded
> wire. It is expensive though.
>
> More about this - Faraday Cage...
> http://en.wikipedia.org/wiki/Faraday_Cage
>
>
>
> "Bob in Phx"  wrote in message
>> thinking of wiring a new house and would like to know what kind of wire
>> to run. cat 3, cat5, cat6 something else???????
>> it will be in the walls, not in air spaces, 2 zone alarm with NC switches
>> all in parallel.,
>>
>> thanks in advance....
>>
>
>