"Donna Ohl" wrote in message
...
On Wed, 8 Oct 2008 03:30:31 -0700 (PDT), ransley wrote:

What caught fire its all metal. Google to see if those have a record
of catching fire. Replacing the element wont make it safe that is not
the cause, or what burned, you have to take it apart to find the
cause. For most it would not be worth the trouble. With a fire there
is likely hidden wiring that is fried.

Hi Ransley,

What irks me is I don't understand how this COULD have happened!
http://www.flickr.com/photos/donnaohl

I mean, it should be pretty simple, right? It's just a big resistor with
220v on one end pushing electrons through it.

Given it's such a simple circuit, I just can't comprehend how this fire
can
happen. For example, there is a half-inch gap in the element as shown
he
http://www.flickr.com/photos/donnaohl/2923845906/

My question, in general, is ...

Q: How can an open resistor arc to the oven metal and how can it arc even
when the switch is turned off and why didn't it blow a fuse if it really
was shorting and what possibly could have been burning when there is
nothing flammable?

How can all this possibly happen to a simple 220v resistor circuit?
It doesn't make any sense. That's why I'm asking here for answers!

Does anyone know the theoretical answer to this question?
Donna

If your in the US, your house is most likely fed 240 volts from a
transformer that is center tapped (neutral) and there is 120 volts from the
neutral to each hot and 240 volts from hot to hot. The neutral is tied to
ground in the breaker box. When the element fails, sometimes it burns
through the insulation to the outer casing which is grounded. Apparantly the
oven contol just removes one hot leg from the circuit while the other is
still connected. normally this opens the circuit and the oven is off, but if
there is a short to ground, like with the bad element, it can continue to
arc since one leg is still connected to hot and there is a short to ground.
I've seen this before when the oven control is set to off and it keeps
arcing when the element burned out.