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determining kiln amperage

updated sat 31 aug 96


Fred Hayward on thu 29 aug 96

A current (pun intended) thread reminded me of one of our most useful
purchaces for the studio. Several years ago we purchaced a Radio Shack
clamp on amp meter. The Cost is about $60 US.

This device simply clamps onto one of the two hot wires leading to your
kiln. (This will require one of these leads to be separated from the
the others. I have exposed the black wire just as it enters the kiln plug
by carefully slicing the sheathing of the cable, then using elecrical
tape, rebound the seathing with the black wire looping out of the cable.
Do not strip the wire of its covering!!!!) You then clamp the meter to this
wire while kiln is on and read from the scale the amperage being drawn.

As you can understand, this provides all sorts of information. First it
answeres accurately what Amperage your kiln is drawing. A reading with
brand new elements will give you a bench mark of the kiln at optimum
operating condition. Then periodic checks will tell you how your
elements are holding up. As they age, your amperage will fall. You will
soon be able to tell how much more your elements have in there useful
life! Finally, if you suspect a broken element or faulty switch, you can
test each ciruit (switch and element) by simply turning on each circuit
independently. If no amperage showing you know you have a problem. The
test can be done quickly even in mid firing without exposing any bare
wires, removing panels etc. (I have even found a faulty switch that went
off on high but just below high it drew full amps- I saved a re-refire.)

> If you are going to use a dryer outlet to power your kiln, you must match
> the amp reading of the kiln (the amount of current that it will drawn when
> it is pulling full power) to the amp rating of the circuit with the dryer.
> Most dryers are about 40 amps while only *small* kilns pull 40 amps. Larger
> kilns pull 50 or 60 amps.

Fred, from the very Dry Rainforest in Whonnock, B.C.