20 amp Paragon kilns actually draw 20 amps. We sometimes rate a kiln at a full 20 amps so that it can still plug into a common 20 amp circuit. This saves the customer the expense of installing a less common higher-amp circuit. Placing a 20 amp kiln on a 20 amp circuit usually doesn't trip the breaker for these reasons:
1) The amperage of a cold kiln is 3% - 4% higher than that of a hot kiln. This is because resistance in elements increases as the elements become hot.
2) Elements draw less amperage as they age.
3) Voltage is usually a little lower than a full 120 or 240 volts. Lower voltage results in lower amperage.
If the breaker trips, the customer should make sure no other appliance is plugged into the same circuit that the kiln is using. Older breakers may trip, because they can become weaker with age. Replacing the breaker with a new one should solve the problem.