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drilling into live wire?

Discussion in 'Electronic Basics' started by andrew_h, Mar 10, 2006.

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  1. andrew_h

    andrew_h Guest

    Don't think this is a stupid question ...

    Out of curiousity (I have no plans to ever try this) - if I was using a
    cordless drill (plastic outer case), and was drilling into the
    wall....and accidentally drilled into a live wire carrying 240V - what
    would happen??????????

    The drill bit would be the only metal part exposed ...... would it just
    spark and probably snap in two ?? worse than this?

    Again, I have no intention of doing this - just wondering,
  2. Tim Williams

    Tim Williams Guest

    Since wires are ran in close pairs, the chances are the bit would tangle in
    such a way that both wires would be at least nicked, causing a short and
    blowing the breaker. The spark could ignite flammable materials in the
    wall, I suppose.

    Nothing would happen to you because, as you note, you are insulated. If you
    were using a corded drill, it probably wouldn't make any difference since
    most are rated as "double insulated", but if I'm wrong on what that means,
    the current would just find an additional path to ground and still blow the
    circuit breaker.

    At any rate, a metal path from wire to person could potentially electrify
    you. This is only a problem if you're touching a ground (concrete and bare
    feet, or unusually conductive soled shoes, etc.), since electricity doesn't
    do anything to you if it doesn't have a place to go.

  3. Phil Allison

    Phil Allison Guest

    think this is a stupid question ...

    ** The drill bit would cut the wire and break the circuit - be a real
    pain having to replace that length of wire hidden inside a wall.

    The worst case scenario is when the person with the drill in their hands is
    standing on a wet floor or ground with wet shoes or bare feet. Also, when
    the person is in the habit of guiding the drill by placing their fingers
    around the drill chuck while it is spinning. They could then certainly
    receive a serious or even fatal shock.

    Another serious hazard is where the person with the drill is using a metal
    ladder - receiving a shock while up a high ladder may trigger them falling
    and being badly injured that way.

    ......... Phil
  4. When put a screw into a cable, which was not where it should have been,
    there was just a loud pop and the fuse blew.

  5. andrew_h

    andrew_h Guest

    Thanks for all your replies - great stuff...

    Going back to the drill - the cordless ones (I use anyway) are all
    plastic, even the chuck part. Therefore, would that mean there is NO
    chance of a shock travelling to my hand and then through my body to
    ground ??? Plastic would not conduct, so basically the tool is double
    insulated - no chance of a shock?

    I was actually drilling a hole yesterday ... cordless drill batteries
    were all flat. So I had to use a power drill - its half metal (handle
    bit is plastic, but chuck and bit behind is metal) and isnt grounded.
    It would have been VERY unlikely there were cables behind ... but after
    drilling one hole I stopped and thought 'dont be a fool'. Might have
    been overkill, but I turned the power to that circuit off and then did
  6. John  Larkin

    John Larkin Guest

    Most US building codes require that unarmored wiring (romex and such)
    be a couple of inches behind the wall surface, or have a protective
    metal plate. The provisions are often ignored.

    If you get a little RatShack amplifier/speaker box and a telephone
    pickup coil, you can track the wires inside the wall pretty well.

  7. andrew_h

    andrew_h Guest


    Tell me more about this Ratshack speaker box and telephone coil

    That sounds very interesting ... so it'll pick up roughly where wires
    are in the wall?

    Better than those 'voltage' detectors......that detects nothing in the
  8. Lord Garth

    Lord Garth Guest

    You could use a pocket AM radio as well.

    Regarding a telephone pickup coil, the power wiring induces a signal
    into the coil. The signal is amplified causing the speaker to buzz when
    the coil is near a power wire.

    A 'fox and hound' is a commercial product that could be used for this
  9. JeffM

    JeffM Guest

  10. andrew_h

    andrew_h Guest

    Those looks really good (drill-stops) ... are hardly used here in
    Australia, as far as I've seen.

    I'll get some!
  11. Jamie

    Jamie Guest

    ah, you mean some one is drilling holes (hammer drill) for para bolts
    into barred conduit ? :))
  12. Not a stupid question at all. I see alarm company installers run a long
    6 ft. bit UP a wall into the attic above where power lines might be
    stapled to the studs.

    This really spooks me as I see so many power lines over a stud that I
    have to push out of the way while drilling DOWN the wall.

    When I have to blindly drill where there just might be a power line, I
    use both a newer model of stud finder with a live power detector. Those
    little power line detector wands don't seem to be as sensitive. Then I
    also use a circuit finder that you plug a transmitter into a live outlet
    and use the probe to listen for a tone.
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