Joan Berkwitz on wed 19 may 04
Hello! A friend has a little Cress FX911 electric, that's the small one. =
We wired her a clean run, very short from the circuit box, with a more =
than adequate circuit breaker and #10 wire. (Specs call for #12 or up) =
And the receptacle is rated properly as well. However, when she fires... =
the receptacle, kiln cord and some of the wall above the outlet get hot =
enough that she can't keep her hand on them. This occurs toward the end =
of the up cycle, of course. It's a new cord, we replaced it a few months =
ago because of the same problem in another location, which we blamed on =
the wiring. Now with wiring we did ourselves, the cord is frying again. =
Is there another possibility that we can look into? They redid the Cress =
911's apparently some time ago, hers is quite new, only a year old or =
so. Came straight from the factory. She doesn't plug and unplug =
it....she will call Cress today but last time they were rather =
uninformative.
Please help! She makes her living off of her artwork and really needs to =
be able to fire safely.
Joanie, in Carlsbad, California
Arnold Howard on thu 20 may 04
Joan, it sounds like a loose connection, either within the plug or the wall
receptacle. The plug may be defective even though it's new.
A loose connection causes the wiring to over-heat. That heat travels through
the circuit, heating up other components. So sometimes the loose connection
is somewhere else than you think.
But I would not fire the kiln again until replacing the cord and receptacle.
Those items are very cheap compared to the cost of a fire. I'm glad your
friend was alert and discovered the problem.
Sincerely,
Arnold Howard
Paragon Industries, L.P., Mesquite, Texas USA
arnoldhoward@att.net
----- Original Message -----
From: "Joan Berkwitz"
Hello! A friend has a little Cress FX911 electric, that's the small one. We
wired her a clean run, very short from the circuit box, with a more than
adequate circuit breaker and #10 wire. (Specs call for #12 or up) And the
receptacle is rated properly as well. However, when she fires... the
receptacle, kiln cord and some of the wall above the outlet get hot enough
that she can't keep her hand on them. This occurs toward the end of the up
cycle, of course. It's a new cord, we replaced it a few months ago because
of the same problem in another location, which we blamed on the wiring.
David Martin Hershey on thu 20 may 04
Hi Joanie,
Arnold is right- there is a loose connection somewhere. My guess would =
be the receptacle- it's sometimes hard to get the screw tight enough on =
those big wires. (The biggest wires in a large main panel can require 90 =
lbs of torque by code!!!) Or like he says, something could be defective. =
This is a good reminder to check our kilns frequently while they are =
firing.=20
I had a similar deal a while back. I fired a load overnight, and when I =
went to check it in the morning not only was the kiln off, but the main =
sub-panel breaker for the whole studio had blown. (100 amps) Needless to =
say I was a bit freaked out at first, but I sat down and thought it out. =
The 50 amp kiln breaker had not thrown- so that meant that there was no =
overload from the kiln itself. None of the other breakers in the panel =
had thrown either. Just to be sure I checked the tightness of all the =
connections at the kiln cord & receptacle, and they were fine.
That left the sub-panel main breaker as the culprit. My guess was either =
a loose wire causing the breaker to overheat, or a defective breaker. =
These breakers are not cheap, but I have gotten a bad one from time to =
time on my building projects.=20
I turned the sub panel off from the main panel, and opened the box up. =
It turned out that BOTH the hot wires connected to the main breaker were =
loose- simple fix. The cause: about 2 years ago I installed a digital =
sub-meter in the studio to monitor the power consumption- mostly to =
easily see how much electricity the kiln was using for different =
firings.=20
This involved installing 2 "D" shaped sensors around the large main =
wires for the sub-panel ahead of the main breaker. I had to wrestle with =
the wires to get the sensors installed, and fit into the crowded panel. =
I guess all this movement loosened up the connections to the main =
breaker a tiny bit.=20
Eventually (after 125 firings) the heating and cooling at the less than =
tight connections caused the screws to back out enough to cause enough =
resistance for the breaker to overheat under the load of the kiln =
firing, and trip the main.
I have fired 35 times since the event without a problem.
Note to self: after working on a sub-panel, ALWAYS check the tightness =
of all breaker connections!
Best, DMH
From Beautiful Hermosa Beach CA USA
where the red tide is in, but the water is finally warm enough
for some serious pier to pier training swims...
Bonnie Staffel on fri 21 may 04
Dear Clayarters,
I am not an expert in electric kiln wiring, however I have been around
electricians who have wired my kilns right to the box and there seems to be
a discrepancy between their own whether it is OK to use aluminum wire
connected to copper wire or that it is not OK. With the former, the
expansion when in use seems to loosen the connections, hence a hot spot.
Just my opinion and listening experience.
Regards, Bonnie Staffel
http://pws.chartermi.net/~bstaffel/default.html
http://www.vasefinder.com/
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