If a dryer, and it blows the breaker right when you plug it in, it's the heating element shorted. If anything else, you have to determine
what the item was switching into when it blew. If a refrigerator and you turn the defrost timer to defrost and it blows the breaker, the short is in the defrost circuit.
If a washer or fridg. would be helpful to put it on a extension cord with breaker.
Sometimes you can find a short with an ohmmeter. Most of the time though, the short only happens when you put 115 volts to the item, 9 volt ohmmeter will not indicate
a short in that case.