Re: Trick to drilling a larger hole without damaging wiring

[Jim <alarminex@xxxxxxx>]

On Jul 23, 10:40=EF=BF=BDam, jawdoc <drbro...@xxxxxxxxx> wrote:
> I want to replace a recessed sensor that someone prior placed a non
> metal contact in a metal door.
> I need to drill out the hole bigger. =EF=BF=BDBut I don't want to bugger =
up
> the wire drilling.
> Is there a special drill or a trick to do this?
> I am scared in this particular door to push the wire up that I will
> not be able to retrieve it.
> Thanks in advance!

In new construction, many times the entry door from the garage to the
house is not installed until some time after the alarm pre-wire is
done but is installed before you're called back for final hook up. At
pre-wire,  I'll usually tie a tag on the wire for the garage door
contact, saying not to bury the wire. I don't tell them to drill a
hole because they wouldn't know where to drill it anyway.
So, many times, the door installer, trying to be helpful, will drill a
small hole in the jamb and pull the wire though. I always bring my
wire to the jamb from the bottom of the door, regardless if the wire
source is from up .... or down. This way I always know which way it's
coming from. So anyway, if he drills like a 1/4 size hole, I'll just
drill a larger hole above it and pull (snake) the wire out of the old
hole and into the new and fill the smaller hole.  If the hole is
larger, like 3/8 or larger but not 3/4, then I use the following
method.

This works for me.

Pull the existing piece of wire out of the hole and with a flashlight
you'll have to look to see which way the wire comes into the back of
the hole. (Mine always come from the bottom of the hole.) Sometimes it
may come straight from the back of the hole. Sometimes from the top or
bottom of the back of the hole. This is important to know so that you
don't cut the wire off when you're drilling the new hole.

Lets' say the wire is coming from the bottom of the back of the hole
about two inches in. I have a flat screw driver with a square shaft
that I use, but you can fabricate a flat piece of metal that will fit
into the existing hole just wide enough to cover the wire beneath it,
to protect it from damage while you're drilling the new hole. With my
screw driver, I can jamb it into the wood at the back of the hole so
that it doesn't get pulled out of the way by the hole saw. Using a
hole saw with a pilot drill, start a larger hole above but
intersecting the diameter of the existing hole. You can drill into the
jamb with the hole saw just barely touching the top of the metal piece
that you're protecting the wire with. Drill slowly. You should wind up
with the larger hole intersecting the smaller hole aprox half or less
than it's diameter. Take out the piece of metal that protected the
wire and pull the wire up ito the channel of the new hole so that it
protrudes out of the larger hole. Mount your larger contact. As you're
mounting the larger contact, fill in the smaller hole with caulk or
silicone, or whatever it needs, to hide whats left of the smaller
hole. Most times, you can barely see the old hole because the lip of
the new contact covers it.

Pull the magnet from the door and do the same thing with the hole saw
if the magnet is larger.

Some times you have to shift the hole saw to one side or the other
because you don't want the larger diameter hole to break out the side
of the jamb or the magnet to be too close the to edge of the door.
Look at it all closely and take  your measurements before you begin.

Others will just drill another hole an inch or so above or below the
old hole and take a chance that they wont cut the wire, since they
have no idea from which direction it's coming to the hole. I'm not
that lucky.

But I did stay at a Holiday Inn last night.