Testing an Electric Blanket

[Nelson]

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.

 

[n cook]

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.

Do you have to test simulating incontinence ?

 

[Dave D]

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.

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

 

[Nelson]

Do you have to test simulating incontinence ?

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

 

[Nelson]

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

Thanks for the "heads up". I have read that the new ones are "safe".
Can you comment?

 

[Stanislaw Flatto]

Thanks for the "heads up". I have read that the new ones are "safe".
Can you comment?

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.

 

[Rich Grise]

Thanks for the "heads up". I have read that the new ones are "safe". Can
you comment?

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

 

[Dave D]

Thanks for the "heads up". I have read that the new ones are "safe".
Can you comment?

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

 

[CRaSH]

Any DIY help would be appreciated.

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

 

[James Sweet]

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.

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.

 

[James Sweet]

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

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.

 

[Stanislaw Flatto]

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.

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.

 

[[email protected]]

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
..
..

 

[Mark Fortune]

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?

Dont forget the fire risk

 

[Dave D]

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?

Slim but possible, but that's perhaps not their primary danger.

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.

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

 

[Fred McKenzie]

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?

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

 

[GregS]

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!

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

 

[Franc Zabkar]

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.)

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

- Franc Zabkar

 

[n cook]

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

- Franc Zabkar

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.

 

[Nelson]

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

- Franc Zabkar

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.