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Testing an Electric Blanket

Discussion in 'Electronic Repair' started by Nelson, Jul 22, 2006.

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  1. Nelson

    Nelson Guest

    Not really electronics, I know, but I'm hoping some one can throw me a
    pointer. I'd like to test for both safety and shorts/opens/too much
    resistance. The only thing I could find on the web is safety testing
    by electric utilities.

    Any DIY help would be appreciated.
     
  2. n cook

    n cook Guest

    Do you have to test simulating incontinence ?
     
  3. Dave D

    Dave D Guest

    If you have the slightest doubt as to its safety, dispose of it. Faulty
    electric blankets are not only potentially lethal because of the shock
    hazard- they are a very real fire risk as well.

    I speak from experience.

    Dave
     
  4. Nelson

    Nelson Guest

    My wife has Multiple Sclerosis and it's no joke to either of us.
     
  5. Nelson

    Nelson Guest

    Thanks for the "heads up". I have read that the new ones are "safe".
    Can you comment?
     
  6. Just a "comment", if, repeat if, you have ANY reservations on using
    something that includes "speed of light" possible fatal media, discard it.
    BTW, what happened to the hot water rubber bottle?
    One of the _best_ replacements I met was a "dashhund" who liked to sleep
    on human bent legs under blanket. Wonderful invention!.

    Good luck.

    Stanislaw
    Slack user from Uladulla.
     
  7. Rich Grise

    Rich Grise Guest

    Well, according to the TeeVee Nooz lately in SoCal, one can be swallowed
    by a 12 foot python, and all he got was indigestion. ;-)

    Cheers!
    Rich
     
  8. Dave D

    Dave D Guest

    Well, realistically they have to be pretty safe to meet modern regulations.
    A new one is likely to be a negligible risk. However, I just don't like the
    idea of mains electricity flowing through a blanket, and when they have some
    wear on them it will inevitably affect the insulation and hence their
    safety.

    Personally, I can't recommend the use of electric blankets at all, but then
    maybe I'm just over cautious ;-)
    I would certainly never use one designed to be left on when you're in bed.
    <shudder>

    Dave
     
  9. CRaSH

    CRaSH Guest

    Plug it in, turn it on, turn out the lights, watch for sheet
    lightening........... d:->))
     
  10. James Sweet

    James Sweet Guest


    There's really nothing to test, either it works or it doesn't. If it's
    physically damaged, don't use it, but if it looks ok and it heats up,
    it's fine.
     
  11. James Sweet

    James Sweet Guest



    Ah it's the greatest thing in cold winters, the wires are heavily
    insulated, they're inside a blanket, and over a sheet. Cloth doesn't
    conduct, what are the chances of actually getting electrocuted?

    Yeah and my house could fall down in an earthquake in my sleep, or I
    could trip and break my neck on my way to the bathroom at night, things
    happen.
     
  12. It IS scientificaly/statisticaly(chose one) proven that most people die
    in bed, ergo sleep like a donkey, standing.

    Have fun

    Stanislaw
    Slack user from Ulladulla.
     
  13. Guest

    James:
    About 5 years ago I had a blanket that woke up both my wife and I with
    what appeared to be dim lightning flashes in the room.... it turned
    out that a short circuit or loose connection developed inside the
    blanket. When we turned on the lights to investigate there was a
    burnt spot on the blanket and we could hear a snapping sound. Even
    thought the blanket was well past it's warranty and we had no receipt,
    the service center we sent it to REPLACED with a new one, NO
    CHARGE...... so from now on we are quite alert as to possible
    problems.... and yes, we still use an electric blanket on our bed.
    electricitym
    ..
    ..
     
  14. Mark Fortune

    Mark Fortune Guest

    Dont forget the fire risk ;)
     
  15. Dave D

    Dave D Guest

    Slim but possible, but that's perhaps not their primary danger.
    You would perhaps have a different attitude if you'd been in a house where
    an electric blanket burst into flames and set the bed alight. Half an hour
    later and my parents would have been under it and asleep. Lucky I was in the
    house at the time- they didn't smell the burning at all but I did and we
    managed to put it out quickly.

    Dave
     
  16. James-

    I think the chances are slim, but the OP had a special problem.
    Considering the risks, one might decide to avoid use of an electric
    blanket in some circumstances, unless there was an additional plastic
    sheet between the user and the blanket. (The alternative of non-electric
    blankets may be an undesireable choice due to the additional weight
    required.)

    As far as testing is concerned, perhaps a blanket could be soaked in a
    saline solution in a conductive tub. Electrical leakage could be measured
    between the tub and the blanket wiring. For a meaningful test, full
    voltage (current limited) would be applied between the wiring and the
    tub. For a safety factor, higher voltage might be used.

    Passing such a test doesn't guarantee that leakage won't develop later
    from normal wear and tear, so you're back where you started!

    Fred
     
  17. GregS

    GregS Guest

    The test would only trip the integral ground fault interupter
    if there was leakage. I have a feeling most all blankets now come with
    fault interupters. Is that true??

    greg
     
  18. Franc Zabkar

    Franc Zabkar Guest

    I'd suggest dispensing with the electric blanket and pre-warming the
    bed with a portable fan heater.

    - Franc Zabkar
     
  19. n cook

    n cook Guest

    Even more fires are started by clothing draped over fires which this is
    equivalent to - highly dangerous. Restricted air supply leads to excessive
    heat build up. The traditional hinged double copper "frying pans" on a broom
    handle with hot coals from the fire, sounds much safer.
    On a related matter the local fire service had a black museum. One of its
    seized exhibits was a home-made bed warmer. Someone started with a soldiers
    steel helmet, nailed some wooden dowels on the inside, nails in the other
    ends to wrap the element wire from an electric fire around.
     
  20. Nelson

    Nelson Guest

    I appreciate all those who have given constructive suggestions. For
    the record, my wife has Multiple Sclerosis one symptom of which is poor
    blood circulation. She is always "cold" even in the summer. More
    blankets, which only keep body heat in, don't help. What is needed is
    a heat source other than her body. Hence the electric blanket. She
    still complains it isn't warm enough and I have no idea how to test if
    it is working properly merely from a heating perspective. It feels
    warm but not hot. I assume, without taking the thing apart, that there
    are a bunch of resistive elements wired in parallel. Thus some could
    be open and the blanket still heat.

    The other concern is safety since, unfortunately, another of her
    symptoms is incontinence.

    The blankets we have are perhaps 20 years old. They still seem to work,
    but do not get very warm. On the other hand, I don't recall how warm
    they are supposed to get. I am sure they are regulated so that you
    don't inadvertently burn yourself from a high setting. I would have
    just gone out and bought a new one if money weren't an issue.

    In searching the web, I noticed many Electric Utilities offer "safety
    tests" for electric blankets, so there must be some protocol. I was
    just hoping someone here knew it although it is hardly "electronics".

    Another article I found suggested that they "used to be unsafe" but
    newer standards have been adopted which make them safe.

    Leaving out the "tin foil hat" concern about electromagnetic fields, I
    assume the main risks are shock and fire. My presumption was that the
    UL certification covered those and the ones I have carry UL
    certification.

    I suppose the best thing to do is to just buy a new one. And yet,
    without understanding the failure modes of the old ones, there still
    remains in my mind a safety concern.
     
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