San Diego electrician explain that with 15-Amp 120V electrical circuits: typical U.S. 120V household electrical circuit uses #14 gauge copper wire and is protected (and thus limited) by a 15-amp circuit breaker. Such a circuit can deliver about 350 watts of electrical power to devices plugged into it, and another roughly 10 watts is consumed by the resistance of the circuit and its devices (receptacles and switches).

20-Amp 120V electrical circuits: typical U.S. 120V 20A household circuits use #12 gauge copper wire and are protected and thus limited by a 20-Amp fuse or circuit-breaker. A 20-amp circuit can provide about 2400 Watts. But as some writers have pointed out, for safety, household circuits are intended to carry less current (about 20% less) than their theoretical maximum. 80% of 2400 Watts is 1920 watts – that’s about what you should expect to obtain from such a circuit.

San Diego electrician, share how they are figuring these numbers? They use the formula from above, Watts = Volts x Amps and plug in the nominal voltage and a guess at the resistance over the electrical circuit before they’ve plugged in anything:

W = 120V x 15 Amps so W = 1800 for our 15-Amp electrical circuit.

W = 120V x 20 Amps so W = 2400 for our 20-Amp circuit.

Example:

If we have a 1500 Watt electric heater running on “high” and thus drawing a maximum of 1500 Watts, plugged into our 20-Amp circuit above, we’ve got another 420 Watts available on that circuit. So we could run maybe another four 100-watt lights on the same circuit.

The real world is a little more complex; lots of devices draw more current when they’re starting-up, especially air conditioners and refrigerators. The electrical engineer (during design) or electrician (during house wiring) choose a circuit breaker that can tolerate that temporary high current but that will trip off if high current continues to flow on the wire.
For further assistant and more information call (800) 233-1950 or visit http://localunited.gositetest.com/electrician-san-diego/