[time-nuts] RG 6 U couplings

[Chuck Harris]

I wouldn't get too hung up over fire rating on such
cables.  Your house and shop is littered with PVC
cabling that will make lots of nice toxic smoke if
it burns.

Fire rated cable, also known as plenum cable, is special
because it is meant to be run in the ducting spaces for
the HVAC system in a commercial building.

In most commercial buildings, the entire raised ceiling
area is the intake duct for the building's HVAC system.

Because air is moving pretty rapidly in the intake plenum,
it tends to feed a fire, and when a piece of wire in an
air plenum burns, it will burn from one end to the other,
spreading the fire and making lots of smoke.... Which,
being in the air intake for the building will spread to
everywhere there is an outlet duct...

If you are planning on running the wiring in your HVAC
air ducts, then by all means use plenum wire, but anywhere
else in your house/shop is a waste.

Burning teflon wire has its own plethora of problems.

-Chuck Harris

Mark Spencer wrote:
> I looked up the part number of the cable I installed and the data sheet says it
> does have Teflon insulation.  It does look different than other Teflon cables I
> have seen though. My main concern was and is the fire rating.  The comments about
> the phase stability are also of interest.   If anyone has this type of data for RG
> 6 style cables I'd be interested in seeing it.
>
> If I ever run new cables to the roof I might pull an new run of rg6 for the GPS.
>
> At one point I was looking at ways to safely route non fire rated hard line to my
> GPS receiver.
>
>
> Sent from my iPhone
>
>> On Dec 7, 2015, at 6:33 PM, Hal Murray <hmurray at megapathdsl.net> wrote:
>>
>>
>> mark at alignedsolutions.com said:
>>> Actually I may be misremembering this.    Am not sure if the cable I used was
>>> Teflon on not.   It did have a defined fire rating though, and I was concerned
>>> about it's phase stability vis a vis temperatures.
>>
>> I was at Xerox in the late '70s when the DEC-Intel-Xerox work on Ethernet was
>> going on.
>>
>> The Los Angeles fire dept was sensitive to smoke from cables.  A friend got a
>> chunk of potential cable from Belden.  It was Teflon coated.  I don't know what
>> was inside.  He took it out on his back porch and hit it with a propane torch.
>> It ignored him.  Well, not quite.  It got smudged a bit, but that wiped off.
>>
>> He took a bigger chunk to Underwriters Lab in Chicago.  They have a setup for
>> testing cables.  It's a cable tray in an enclosure that's 20 ft long and a few
>> feet wide and 3 or 4 feet tall.  A big gas pipe goes in one end.  There is a
>> chimney at the other.  They put the cable in, replace the lid and light it up.
>> The Teflon cable didn't have any problems.
>>
>> Teflon is expensive.  After a couple of years somebody worked out a cheaper
>> compound that was good enough for the fire people.
>>
>>
>> -- These are my opinions.  I hate spam.
>>
>>
>>
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