I plan on installing a new telephone demarcation box on the inside wall of
my garage near where 2 pairs of wires come out of a conduit. The existing
demarc box is old, ugly, and accessible from the outside where it could
easily be opened and the wires cut. I'm thinking in terms of greater home
security and better DSL performance.
While I can isolate the house wiring from the live wires via unplugging an
RJ11 disconnect, I will have to first move the live telephone pair from the
old demarc to the new demarc. Is it enough to carefully use a pair of
insulated pliers to move and connect a wire over without causing all sorts
of havoc at the central office? Many years ago I performed a similar
procedure by moving a jack. When I was through the telephone immediately
rang. When I answered it was Bell Telephone saying they detected a fault on
my line because an indicator "popped up". I'm thinking I may have
accidentally shorted the wires. I told the woman on the phone that
everything on my end was normal (this was back in the days when the phone
company owned everything, including the telephone and jacks).
The only other and perhaps safer way to do this is to first connect a new
pair of telephone copper wire to the new demarc and then crimp and join the
wire to the live pair coming out of the conduit. Is that how the pros do
it? The only thing with this is that I'd need to find the correct crimp
connectors. I think the telephone company uses the kind where you insert
both wires unstripped and then squeeze down to cut the insulation and make
the connection. I'm trying to avoid using crimp connectors though and would
prefer to connect directly to the new demarc terminals. With each crimp
connector comes the risk of an imperfect electrical contact with degraded
voice and DSL performance.
I think lineman work on high voltage with less caution and concern than
you're giving telephone wires. Just try not to short the wires together and
you'll be fine. If you're concerned about a shock hazard, wear light weight
Nobody else said it, so I will- in many areas, you do not own the demarc
box, and your telco will take a dim view of you moving/replacing it
without talking to them first, especially if you have to extend the drop
wires, which they do own. Not to mention, if they come out on a service
call, you will need to be home. The whole idea of the 2-side demarc box
was to provide a semi-secure outside box that their techs could get to
any time. They may come back and replace your butt splice with a new
demarc box, and charge you for it. You will have to run the ground wire
back outside to the same attachment point in any case.
If you truly have security concerns (like a neighborhood with lots of
breakins), I'd call and talk to them about armoring the drop in conduit
where it is within reach of the ground (unless you already have buried
service), and swapping the box out for a metal one with a security screw
or lock. They are used to that for light commercial work.
Unless your box is full of bugs and corrosion, it is unlikely to make
any difference in your DSL connection. A straight run from the demarc
box to your DSL modem, bypassing the rest of the inside wiring, is much
more likely to help.
If i had to be in an area that required an alarm
If I had an alarm system that used the telephone line to signal an
intruder, I would want the wires to be secure.
As the telephone wiring is normally an open circuit you can cut the wires
loose any way you want to. There is less than 50 volts on the wires unless
it is ringing and then it has about 90 volts on it during the ring.
Normally unless you are wet and sweaty you will not feel the lower voltage
and if it does ring it will usually just make you hirt yourself when you get
shocked. Not normally life threating to a healthy person. If you do short
the wires for a second or so it is no problem.
I'm pretty sure the demac belongs to the phone company, you probably need to
talk to them about replacing and/or moving it.
That being said, I wouldn't worry about any special precautions working on
the wires. Telephone voltage is about 48VDC, and about 90V AC when ringing,
but it's very limited current (I believe it's something around 50ma).
It's usually 22 or 24 gauge wires, the last thing the phone company wants is
the wires overheating because someone jammed something in the wall jack.
Even shorting them out isn't going to cause any havoc at the central office.
Again, since it's current limited it's not going to be any kind of overload
at their end. The main effect is that it will look "busy" to anybody
calling. I imagine if it's left that way for any amount of time (days?),
they might send out a tech to check the wires, but since they don't own the
whole system anymore, they probably don't monitor the end connections as
closely unless customer contacts them with an outage.
About a year ago we were out of town for a week. When we got back, we
didn't have a dial tone. Found out from some friends that our phone had
been "busy" for about three days. I checked each jack and found one on an
exterior wall that had corrosion, apparently from condensation that had
formed on the pins. Soon as I disconnected that jack, we got our dial tone
back. Never heard anything from the phone company about it.
By the way, those crimp connectors are available from Home Depot, Lowes, and
Radio Shack, etc.. The one's I've seen are called Scotchlok from 3M, but I
think others make them too. They're filled with some waterproof (silicone?)
gel, so they seal when you crimp them. Considering all the connections
between your house and the central switching office, I wouldn't worry too
much about signal loss from using them on your phone wires. Of course on
the Ethernet network side of your DSL modem, you don't want to use them; not
because of the signal loss, but because it messes up the twisted pairing of
the wires (not a problem on the phone side).
On Sun, 28 Sep 2008 23:56:54 +0100 (BST), Naval Squid
Dont even try this. Hire an electrician. This is far too dangerous
for the average homeowner. One wrong move and you'll be a goner.
Many people die each year from working on phone wiring, and sometimes
they even burst into flames if they directly contact the hot wire (the
red one). Think about your offspring. A funeral is more costly than
But the demarc box isn't yours. It is the line of demarcation between
you and the telco. It is always furnished by them and is supposed to be
readily accessible so they don't need to get in to troubleshoot.
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