LOWELL BAKER on tue 7 may 96
I am not suggesting that anyone test the following;
It seems to me that the elements in your kiln are no dofferent that
the coils on your kitchen range. Why is it that we don't get
electricuted every morning?
My suggestion is that the electricity takes the path of least
resistance. That's one of those laws... The least resistance is the
wire even though it gets hot because there is some resistance. If
this law gets repealled then I will have to give up my favorite iron
skillet.
It further seems to me that the danger in touching an element that is
charged is only if that element is broken, allowing you to close the
circuit or if the metal tongs go from charged element to ground and
become the better conductor. even in this case the power would be
conveyed through the tongs and not through the tonger.
A final note: All this out loud thinking is from a person who
endured $12,000, just last year, in medical costs due to an injury
that was directly related to getting shocked. It seems that I am
becoming a better conductor the balder I get. I,m past a half a
dozen AC shocks this year and a couple of enlightening static shocks.
My wife won't stand next to me in a storm.
so who knows the answer?
Lowell
The University of Alabama
"Ronald Galyen - Teacher - Mt. Carmel Elem RGALYEN" on tue 7 may 96
I may be wrong BUT my kitchen range elements are encased in some kind of
coating. We just had one burn out.
Don't try touching a kiln element like a burner.
You are right about resistance. And resistance is what makes the kiln
hot. You (especially if well grounded) would probably be less
resistant. And therefore the path taken.
===================================
= Ronald W.Galyen =
= rgalyen@mars.esc.k12.in.us =
= Brookville, Indiana, U.S.A. =
===================================
On Tue, 7 May 1996, LOWELL BAKER wrote:
> ----------------------------Original message----------------------------
> I am not suggesting that anyone test the following;
> It seems to me that the elements in your kiln are no dofferent that
> the coils on your kitchen range. Why is it that we don't get
> electricuted every morning?
>
> My suggestion is that the electricity takes the path of least
> resistance. That's one of those laws... The least resistance is the
> wire even though it gets hot because there is some resistance. If
> this law gets repealled then I will have to give up my favorite iron
> skillet.
>
> It further seems to me that the danger in touching an element that is
> charged is only if that element is broken, allowing you to close the
> circuit or if the metal tongs go from charged element to ground and
> become the better conductor. even in this case the power would be
> conveyed through the tongs and not through the tonger.
>
> A final note: All this out loud thinking is from a person who
> endured $12,000, just last year, in medical costs due to an injury
> that was directly related to getting shocked. It seems that I am
> becoming a better conductor the balder I get. I,m past a half a
> dozen AC shocks this year and a couple of enlightening static shocks.
> My wife won't stand next to me in a storm.
>
> so who knows the answer?
>
> Lowell
> The University of Alabama
Kevin Hansen on tue 7 may 96
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The element in a kitchen range is constructed differently than a kiln element.
The actual wire that conducts the current is sealed inside a metal tube with
a refractory powder (i.e. alumina) to act as electrical insulation. The element
in a kiln is an uninsulated wire (usually nichrome or other high temp alloy). To
a kiln element can cause a severe shock and even death if enough current flows
through the heart to cause fibrillation. Always unplug a kiln (if possible) or a
double check that it's off before reaching inside with anything.
Another misconception I often hear is that electricity takes the path of least
resistance. This is false. The current through a circuit is proportional to the
resistance of that circuit. I=E/R (I is current, E is voltage and R is resistanc
It only takes a few milliamps through the body to cause problems.
Kevin Hansen ( hansen@aztek.com)
Boulder, CO where the weather has been making it really hard to work inside.
----------
From: LOWELL BAKER[SMTP:WBAKER@woodsquad.as.ua.edu]
Sent: Tuesday, May 07, 1996 3:55 PM
To: Multiple recipients of list CLAYART
Subject: ELECTROCUTION/???
----------------------------Original message----------------------------
I am not suggesting that anyone test the following;
It seems to me that the elements in your kiln are no dofferent that
the coils on your kitchen range. Why is it that we don't get
electricuted every morning?
My suggestion is that the electricity takes the path of least
resistance. That's one of those laws... The least resistance is the
wire even though it gets hot because there is some resistance. If
this law gets repealled then I will have to give up my favorite iron
skillet.
It further seems to me that the danger in touching an element that is
charged is only if that element is broken, allowing you to close the
circuit or if the metal tongs go from charged element to ground and
become the better conductor. even in this case the power would be
conveyed through the tongs and not through the tonger.
A final note: All this out loud thinking is from a person who
endured $12,000, just last year, in medical costs due to an injury
that was directly related to getting shocked. It seems that I am
becoming a better conductor the balder I get. I,m past a half a
dozen AC shocks this year and a couple of enlightening static shocks.
My wife won't stand next to me in a storm.
so who knows the answer?
Lowell
The University of Alabama
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Marvin Bartel on wed 8 may 96
On the question of placing raku tongs in an electric kiln ---
I'd turn the kiln off before placing metal tongs inside. I agree
that one would not be seriously shocked so long as the elements are whole.
I would not want my metal tongs on the live end of a broken element and
touch a ground at the same time. The jacket of an electric kiln would be
grounded.
Unplugging is a pain to do, but unless I know for sure how the
curcuit is set up, simply switching it off with the kiln element switches
may not disconnect both pieces of a broken element. Murphey's law could get
me. I would not chance it.
If I wanted to use an electric kiln for raku, I'd hope the curcuit
breaker box was close enough. It is a lot easyier than unplugging, and just
as effective. Unplugging is the only absolutely safe way. Whenever I have
a student assistant repair a kiln, I insist that they unplug it because the
curcuit breaker is in another room, and another person could unintentionally
switch it on.
++++++++++++++
Marvin Bartel, Art Dept
Goshen College, Goshen, IN 46526
marvinpb@goshen.edu
http://www.goshen.edu
++++++++++++++
.. . . on being influenced by a good idea . .
"Don't borrow it. Steal it. Make it your own."
from poet, Nick Lindsay
jpyle@hs.gettysburg.edu on wed 8 may 96
Lowell:
I'm only going on a warning someone gave me, and don't have the nerve to
prove them wrong, even in the face of what seems like perfectly logical
information.
Perhaps the possibility of breaking an element with tongs and/or ware is
the part of the caveat.
Judy Pyle
Richard Burkett on wed 8 may 96
WAIT A MINUTE! Electric kiln elements can be intact and STILL offer a
potentially lethal shock if turned on. As they are resistance elements the
potential voltage above ground (that's the part we're worried about as the
human is usually the grounded object and they're connected to 220VAC) will
vary with the lenght of the elment from the point where the elements are
connected to the line (the switch end) to the mid-point. The end near the
connection point has close to the full voltage! The middle of the element -
exactly halfway - may have little voltage potential above ground. Raku tongs
and a human would provide a MUCH lower resistance pathway for the electricity
if you touch the elements nearer the connections, and electricity
preferentially follows the path of least resistance.
Personally I wouldn't bet on only ever hitting just that mid-point on the
element with the metal raku tongs! TURN THE KILN OFF!
Richard Burkett -
School of Art, Design, & Art History, SDSU, San Diego, CA 92182
E-mail: richard.burkett@sdsu.edu <-> Voice mail: (619) 594-6201
PRICE@MASTER.PS.UCI.EDU on wed 8 may 96
At the risk of sounding like an alarmist, I would like to add that just
turning a kiln off before touching the elements may not always be enough --
you should unplug it (or turn off it's circuit breakers).
WHY? Well most kilns use 220 (or 230 or 240) volts. That means that the
elements are connected at BOTH ends to HOT wires. Now if the person that made
you kiln installed "double-pole" switches, when you turn off that switch
(and assuming that the switch is working properly) both of those hot wires
will be disconnected from your elements at the same time, and all is OK.
BUT if "single-pole" switches were installed instead, only one end of the
elements are disconnected from the electrical source. This is enough to
turn off the kiln element, but if you touch the element you can get zapped!
Needless to say, single-pole switches are cheaper than double-pole switches.
And it is probably against the electrical code in most areas to use a single-
pole switch on 220V equipment, but unfortunately it does happen. I saw such
a kiln a few years ago.
So unless you KNOW that your kiln uses double-pole switches and that they are
working properly, don't touch those elements even when the kiln is turned off
by those switches -- unless it is also unplugged from the wall.
By the way, it is not always obvious when the double-pole switches are
malfunctioning. If one pole is "frozen" on, the element will turn on and off
as you expect; however, it will be acting like a single-pole switch and the
element will still be electrically hot.
Bottom line -- always unplug it before touching the elements even if you hve
double-pole switches.
LeRoy Price
Ronald D. Hicks on wed 8 may 96
Thought I'd add this question / comment regarding safe utilization of
electric kilns:
Isn't it possible to experience electrocution by reaching inside of a kiln
WITHOUT touching anything...(assuming the kiln is still on)......doesn't
the red heat, itself, carry the electrical charge?
At any rate, I'd sure listen to all the folks who are saying UNPLUG the
kiln first! Switches which are worn, damaged or porrly connected could
suddenly transfer a charge without warning.
Old potters never die, they just slip away! At least, that's what I'd hope
for all of us working with the potential hazzards on the studio.
Ron in Kansas City.
ROBERT POGSON on thu 9 may 96
LB> It further seems to me that the danger in touching an element that is
LB> charged is only if that element is broken, allowing you to close the
LB> circuit or if the metal tongs go from charged element to ground and
LB> become the better conductor. even in this case the power would be
LB> conveyed through the tongs and not through the tonger.
Touching a live element in a kiln is not quite the same as a stovetop.
The elements on MOST stoves is an element in the form of a wire inside an
insulator and enclosed in a steel tube. The kiln is a bare element in most
cases. Even then, like birds on a high tension wire, you're OK until you
touch another conductor at ground potential or another electrical wire.
Then SOME of the current WILL pass through your body and it only takes
a few milliamperes to stop your heart or cause your muscles to throw you
around. One can always switch the kiln off for the period of any
manipulations you need to do on it.
.... nfx v2.8 [C0000] Flame: flatulence combusting.
Henry Pope on thu 9 may 96
At 10:58 PM 5/8/96 EDT, you wrote:
>----------------------------Original message----------------------------
>At the risk of sounding like an alarmist, I would like to add that just
>turning a kiln off before touching the elements may not always be enough --
>you should unplug it (or turn off it's circuit breakers).
>
>WHY? Well most kilns use 220 (or 230 or 240) volts. That means that the
>elements are connected at BOTH ends to HOT wires. Now if the person that made
>you kiln installed "double-pole" switches, when you turn off that switch
>(and assuming that the switch is working properly) both of those hot wires
>will be disconnected from your elements at the same time, and all is OK.
>BUT if "single-pole" switches were installed instead, only one end of the
>elements are disconnected from the electrical source. This is enough to
>turn off the kiln element, but if you touch the element you can get zapped!
>Needless to say, single-pole switches are cheaper than double-pole switches.
>And it is probably against the electrical code in most areas to use a single-
>pole switch on 220V equipment, but unfortunately it does happen. I saw such
>a kiln a few years ago.
>
>So unless you KNOW that your kiln uses double-pole switches and that they are
>working properly, don't touch those elements even when the kiln is turned off
>by those switches -- unless it is also unplugged from the wall.
>
>By the way, it is not always obvious when the double-pole switches are
>malfunctioning. If one pole is "frozen" on, the element will turn on and off
>as you expect; however, it will be acting like a single-pole switch and the
>element will still be electrically hot.
>
>Bottom line -- always unplug it before touching the elements even if you hve
>double-pole switches.
>
>LeRoy Price
Nicely clarified re switching. An alternative to pulling the plug, and for
those direct connected, you can turn the current off at the breaker: switch
off the breaker at the service for the studio/ house. Good to know where
these things are and how they operate. Think breaker when messing around
with electricity. Not such a good thing to keep pulling the plug at the
wall as your handling heavy wires that can apply a lot of torque on the
connections at the kiln.
Henry Pope
C'ville, VA
>
c. van riemsdijk on sat 11 may 96
I have to strongly disagree with the note from Lowell about electrocution.
The heating elements in the stove are insulated, therefore get hot, but the
current flowing through does not reach the parts you can touch. If it does, you
have a mortally dangerous stove!
In an electric kiln these elements are not insulated, they are "alive" untill
the kiln is switched off.
In my country (the Netherlands) it is illegal to sell a kiln without a proper
safety door switch, wich will shut the electricity off when you open the kiln.
When a wire is broken, the electricity can not "flow" through it, and therefore
it is not "alive". But do not touch if the kiln is active, and plugged in,
because you will become the "missing link" and get shocked.
Touching a "whole" element will get you shocked too, because the flow will split
up and follow both paths
(think of a extensioncord with multiple sockets...) though the amount of Volts
might be less....
It still can be your death!
Case has been known that someone died of electric shock with only 47 Volts.
(of course, he was sitting in a bath, and a electrical welder fell in (wonder
how you manage that;-0)
I dont know about hot air being condictive, but it pays to be carefull.
Please be carefull with electricity.
Carolien, in lovely sunny Haarlem.
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