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Re: Which security wire to use?



On Fri, 7 Jun 2013 08:50:51 -0400, "ABLE1" <nospamhere@xxxxxxxxxxx>
wrote:

>
>"Pat" <pat@xxxxxxxxx> wrote in message
>news:1eeuq85ftrjssmdhlu2v6fhhjb4ui9se7c@xxxxxxxxxx
>> On Wed, 05 Jun 2013 06:50:59 -0500, G. Morgan
>> <graham@xxxxxxxxxxxxxxxxx> wrote:
>>
>>>Don Wiss wrote:
>>>
>>>>While renovating my kitchen I want to run inside the walls the wires for
>>>>some security detectors. I understand I need 22 gauge 4 wire for the
>>>>rate-of-rise and carbon monoxide detectors. But looking online I see I
>>>>have
>>>>a choice of solid or stranded. And shielded or not. For the one 500' roll
>>>>that I would need to buy the prices are close enough that price isn't the
>>>>issue.
>>>>
>>>>I would also run a wire for the door contact. It only needs 2 wire, but I
>>>>don't want to buy another roll when 500' is more than enough for all
>>>>three
>>>>devices.
>>>
>>>Don,
>>>
>>>For the heat detectors and CO detectors you need to run fire-rated wire.
>>>18 AWG, unshielded 4 conductor solid is preferable and if any of it will
>>>go between floors you need riser rated wire (FPL-R).  The "P" stands for
>>>plenum, which should always be used as non-plenum cable jackets give off
>>>toxic fumes when on fire.
>>>
>>>For the burglar alarm devices, 4 conductor 22 AWG stranded is preferred -
>>>get plenum rated for that too.
>>>
>>>You *could* use the fire wire for the burglar alarm devices, but it's too
>>>hard to work with and harder to conceal for contacts.
>>>
>>>So you should plan on buying two rolls, one for the fire devices 18G (and
>>>CO detector) and another bag (500") or box (1000') of 4C 18G burglar
>>>alarm wire.
>
>
>> Why is solid preferred for the fire devices.  I am not questioning
>> that it is, but just interested in the reason.
>>
>> Pat
>
>In simple terms:
>
>Because of the supervision integrity or the wire and system.  If you used
>stranded wire and all strands broke but one, you would still have continuity
>and proper supervision.  However it will not hold the current draw of the
>load when needed in actual fire.  With solid wire, if it breaks there is a
>trouble generated and someone will be dispatched to fix the problem.
>
>Les
>
Thanks for the explanation.  I guess that makes sense.  It seems like
solid is more apt to break from stress and could be just about to
break when the fire erupts and causes something to move.  I have no
real world experience with either type in a fire, though, so my "it
seems like" thoughts could easily be wrong.



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