You should never load a breaker more than 80% of its rating, as a good engineering practise. When running at 100% of their rating, they will trip occasionally.
A 12 Ga wire is rated for 20 amperes in the NEC
If you have a poor fitting plug (loose in the receptacle), this creates a point of resistance. This will act as a small heater. Then if the resistance is only 1 ohm in the plug-to-receptacle connection, this 1 ohm resistance will create 400 watts at the resistance, assuming the current flow is 20 amperes, it will be less).
TexMav
4800 watts / 240 volts = 20 amps.
You need a 25 amp breaker and wire, preferably 30 amps. You need #10 or #8 wire.
12 gage is rated at only 20 amps, so that is overloaded. The plug and socket are probably only rated at 20 amps, so you need to get a better socket and plug. And the 20 amp breaker is overloaded also.
Yes, the specs on the link are not correct for wire size and breaker.
you should also install this, from the spec:
"IMPORTANT: Some areas such as Canada and Europe require a lid or door safety switch on kilns"
The specs given by the company are ambiguous.
The oven might be wired with AWG#12 oven wire internally
for individual branches, and it might have internal fusing
at 20 Amperes.
The supply wiring length will automatically push the current
value over 20 Amps.
The wiring from your supply to the oven must be derated for
length, ambient temperature, conduit loading and other factors.
For the power level involved, the oven should be hard wired to
a safety/service switch and not plugged in.
Providing the power supply is a task for a licensed electrician
who will know all of the above, and additional factors peculiar to
your occupancy and local Code.
Both of the previous answers are correct, but probably
incomplete.
MELTING AT THE PLUG WAS CAUSED BY BAD OR RUSTY JOINS BETWEEN WIRES AND PINS.
IF CONSUMED POWER WAS ALWAYS AT 4800W, 20A BREAKER WOULD NOT HOLD LONGER LIFE. REPLACE IT WITH 25A. FOR MORE SAFETY MEASURE, REPLACE 12 GAUGE WIRE WITH 10 TO REDUCE WIRE HEAT AS FULL LOAD 4800W IS ALWAYS ON.
I had my kiln wired according to specs and it melted the plug, I'm pretty sure the company's specs are wrong but they don't agree. here is the adress to my kiln's info http://www.paragonweb.com/F240_with_Top_and_Side_Elements.cfm
