eric stromberg
Senior Member
- Location
- Texas
I do not even know if I have ever held a 20 amp plug in my hand. What sorts of 120 volt single phase devices use a plug that would not fit into a 15 amp receptacle, but that would fit into a 20 amp receptacle?
Charlie,
A 20 Amp cord cap is quite common on Audio amplifiers. Manufacturers try to get the maximum that they can out of an audio amp. For a 20 Amp circuit, 1920 Watts is the maximum for a single cord and plug connected device. For a 15 Amp circuit, it's 1440 Watts. Let's round the 1920 figure on up to 2000 for the sake of conversation. Let's also estimate that audio amps are about 70% efficient. 2000 Watts input becomes 1000 Watts per channel. At 70%, the output that is available is 700 Watts per channel. This is why there are so many amps on the market that are around 700 Watts per channel. There are some amps that are still connected to a 20 Amp circuit that have higher ratings than this, but these are peak ratings that depend on stored energy in the power supply of the amp.
Eric Stromberg, P.E.