Susan Ross on sun 8 feb 98
Hi All --
Thanks to everyone who responded to my concern about The Air We Breathe. We're
moving in the direction of a HEPA air filtration unit for the studio as well
as other preventative measures. I'm feeling better already!
Onward to another question for the electrician gurus:
Can you run a 48 amp 240 volt computerized kiln on a 50 amp breaker? I know
the recommendation is 60, but would a 50 amp breaker actually "hold" a firing
to ^04? What about ^5? If not, what would happen? Would the breaker trip each
time?
Also, is the wire gauge the same for a 50 or 60 amp if the distance is short?
Would that be a #6?
I don't plan on doing any wiring...just trying to educate myself.
TIA
Su
Potting in Piedmont, CA
Kenneth D. Westfall on mon 9 feb 98
SU
No the 50 amp breaker will not handle a 48 amp load. The wiring for a
50 breaker in not the same for a 60 amp breaker and I would suggest you
check in the National electrical code hand book and any other codes
requirements in your area before choosing a gauge wire. How ever, you
could hire a professional who has a code book handy and insurance to cover
damages if it is not done correctly.
At 10:39 PM 2/8/98 EST, you wrote:
>----------------------------Original message----------------------------
>Hi All --
>
>Thanks to everyone who responded to my concern about The Air We Breathe.
We're
>moving in the direction of a HEPA air filtration unit for the studio as well
>as other preventative measures. I'm feeling better already!
>
>Onward to another question for the electrician gurus:
>
>Can you run a 48 amp 240 volt computerized kiln on a 50 amp breaker? I know
>the recommendation is 60, but would a 50 amp breaker actually "hold" a firing
>to ^04? What about ^5? If not, what would happen? Would the breaker trip each
>time?
>
>Also, is the wire gauge the same for a 50 or 60 amp if the distance is short?
>Would that be a #6?
>
>I don't plan on doing any wiring...just trying to educate myself.
>
>TIA
>Su
>Potting in Piedmont, CA
>
Kenneth D. Westfall
Pine Hill Pottery
RD#2 Box 6AA
Harrisville, WV 26362
pinehill@ruralnet.org
DON'T GET STUCK IN THE MUDPIES--K & T
Tim Stowell on mon 9 feb 98
What can be done and what should be done are often two completely
different things. I am not an licensed electrician, and while I feel
comfortable rewiring a kiln, installing an outlet or light in my home
when the wiring already exists. Hire a local electrician to come and look
at what your doing. I have an established relationship with MY
electrician. He understands what I need to know and how kilns should be
connected to the grid. It's worth the money for the piece of mind. If you
make a mistake or get bad advice the building could burn down or
worse........PAY DA MAN
Tim
Tim Stowell Gerard Stowell Pottery
Stacey Gerard 290 River Street
tstwll@juno.com Troy, NY 12180
(518)272-0983
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Al Pfeiffer on mon 9 feb 98
As with most clay questions the answers are not simple, but here's a little
info to help. The recommendation of using a 60 amp breaker probably comes
from a standard derating for most local building codes and dictated primarily
by the NEC (national electrical code) written by various underwriters such as
the fire protection people. I believe that most breakers and wiring are
derated to 85% of capacity for safety reasons. Therefore the 60amp breaker
for a 50amp load. Also, wiring works this way as well but gets more
complicated depending on the type of insulation, # of conductors in a cable or
conduit, temperature range in the environment, and whether it is open or
enclosed in conduit. Generally 6 ga. is OK for a short run, but check with
your local supplier based on your cable type. I use 4 ga. for less voltage
loss and additional safety margin at little extra cost. Will a 50amp breaker
hold a 48amp kiln rating - probably but... Most breakers are thermal
magnetic and like cones work to some degree on the total heat experienced.
When you draw current there is an element which heats up and if too much power
is drawn too quickly the element causes the breaker to trip. There is also a
magnetic component which is calibrated to trip when any excess current draw
is detected. The magnetic element is quick acting the thermal slow and
intended for different conditions. The elemnts in your kiln are resistive and
as such generally do not have a high inrush current to trip the magnetic
portion of the breaker but when you run this close to a breakers limit (48 of
50) you run the risk of the thermal portion of the breaker disconnecting the
circuit. On an electric control generally the kiln is running in a
proportional mode which means some time on and some off to keep within your
temperature ramping profile. This gives the breaker some time to "cool off"
between draws but as the temp. gets closer to final or the ramp gets faster
there is less cooling time both for your breaker and wiring and therefore
potential problems. Therefore the answer is yes you could probably run on a
50 amp breaker with 6 guage wire but why bother for the little incremental
cost difference and possible problems with safety and inconvienience of
kicking the circuit just when you're approaching temp.? Al Pfeiffer
Wendy Hampton on tue 10 feb 98
I just wired for a new kiln room. Used a #4 copper wire and a 60 Amp circuit.
Better safe than sorry.
Wendy from Bainbridge Island
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