Re: Door Bell Install Via Homerun Closet

["petem" <petem001@xxxxxxxxx>]

"G. Morgan" <usenet_abuse@xxxxxxxxx> a écrit dans le message de groupe de
discussion : pr0mb51nevu1smb1u6icqqhqsci0n98e0n@xxxxxxxxxx
> On Wed, 23 Sep 2009 08:17:09 -0400, "Petem" <petem001@xxxxxxxxx> wrote:
>
>>nope its a mess in preparation.. a short can happen , and if does what
>>protection does the OP have against a fire.. none
>
> I advised him to put an inline fuse in there, but realistically a short
> will
> simply pop the secondary on the x-former.
>

ok if its fused... but who put fuse on a doorbell? And the OP never talked
about that.

and what about the transfo, is it a class 1 or a class 2, a class 2 transfo
will pop open on the primary if the secondary get overloaded, but not a
class 1, since the OP is a DIY he could easily go to a electronic surplus
store and buy a class1 transfo, they are really cheap for 16 to 24 volt ...
and a small 40 VA would do the job... now think 40 VA or 40 watt on a small
22 wire, yup we know he is supposed to use 4 not just one wire, but lets
think about a catastrophic failure, were only one of the 4 wire is properly
connected for what ever reason(could be rats or mice chewing the cable
ect.).

this small wire will over heat quite fast if the cable get sorted somewhere
in the wall (again from the rat) what do you think of this scenario? likely
to happen.. likely not, could happen yes, code say that you should not used
isolated wire to build up a gauge, its ok to use multiple tread of wire is a
single wire, they all touch each other all along the cable so if one fail
its connecting back a few micrometer after...But that's not the case in
cat5e cable...

code have been made cause someone once said, its ok I will use multiple wire
to provide power somewhere, all of them together can carry the current
needed, but shit happen and some of the conductor failed then everything
failed..

the gauge is supposed to be 16 he should use that.

> There is not enough heat to generate a fire in your scenario, even with a
> dead
> short.  The current is too small to melt anything.
>

see answer on top..

> So....Let me ask you this:  What about PoE?  It is rated for about ~460mA,
> where's your concern for a fire there?
>

PoE is protected against overload, and they only use 2 wire........why do
you think there is an overload protection? the max amp output is around 500
ma...how do you think they achieve this? by putting protection, cant have a
fire there...

but do remember in the OP case we are talking about around 40 VA.. or 2.5
amp at 16 volt... its far from 500 mA at 5 volt, or 2.50 VA

one thing you should consider, with a small 1.5 volt battery one can solder
a joint in a circuit.. with this:

http://www.amazon.com/ColdHeat-20128CH-Classic-Soldering-Tool/dp/B000RWCRAM

and there is the fact that a 40 watt iron can burn wood, again, simple logic
should lead you to say that there is a probability, if some condition are
there, for a catastrophic failure. that's why the code say 16 gauge in a
single wire for doorbell...


Bass should be happy he now have friends hellping him, but still he wont
win... ;-)