The branch circuit supplying the outlets in a typical home kitchen is wired with #12 conductor and is protected by either a 20 A fuse or a 20 A circuit
breaker. Assume that the following 120 V appliances are in operation at the same time: a coffeemaker, egg cooker, frying pan, and toaster. Will the circuit be interrupted by the protective device? The branch circuit supplying the outlets in a typical home kitchen is wired with #12 conductor and is
protected by either a 20 A fuse or a 20 A circuit breaker. Assume that the following 120 V appliances are in operation at the same time: a coffeemaker, egg cooker, frying pan, and toaster. Will the circuit be interrupted by the protective device?
Question 10.2: The branch circuit supplying the outlets in a typical home k...
From Table 10.1, the total average power demanded by the four appliances is
P = 1200 + 516 + 1196 + 1146 = 4058 W.
The total current in the protective device is
I_{eff} =\frac{4058}{120} \approx 33.82 A.
Yes, the protective device will interrupt the circuit.
TABLE 10.1 Annual Energy Requirements of Electric Household Appliances
| Appliance | Average Wattage | Est. kWh Consumed Annuallya |
| Food preparation | ||
| Coffeemaker | 1200 | 140 |
| Dishwasher | 1201 | 165 |
| Egg cooker | 516 | 14 |
| Frying pan | 1196 | 100 |
| Mixer | 127 | 2 |
| Oven, microwave (only) | 1,450 | 190 |
| Range, with oven | 12200 | 596 |
| Toaster | 1146 | 39 |
| Laundry | ||
| Clothes dryer | 4856 | 993 |
| Washing machine, automatic | 512 | 103 |
| Water heater | 2475 | 4219 |
| Quick recovery type | 4474 | 4811 |
| Comfort conditioning | ||
| Air conditioner (room) | 860 | 860^{b} |
| Dehumidifier | 257 | 377 |
| Fan (circulating) | 88 | 43 |
| Heater (portable) | 1322 | 176 |
| Appliance | Average Wattage | Est. kWh Consumed Annuallya |
| Health and beauty | ||
| Hair dryer | 600 | 25 |
| Shaver | 15 | 0.5 |
| Sunlamp | 279 | 16 |
| Home entertainment | ||
| Radio | 71 | 86 |
| Television, color, tube type | 240 | 528 |
| Solid-state type | 145 | 320 |
| Housewares | ||
| Clock | 2 | 17 |
| Vacuum cleaner | 630 | 46 |
a) Based on normal usage. When using these figures for projections, such factors as the size of the specific appliance, the geographical area of use, and individual usage should be taken into consideration. Note that the wattages are not additive, since all units are normally not in operation at the same time.
b) Based on 1000 hours of operation per year. This figure will vary widely depending on the area and the specific size of the unit. See EEI-Pub #76-2, “Air Conditioning Usage Study,’’ for an estimate for your location.
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