Anonymous
Anonymous asked in Science & MathematicsEngineering · 4 weeks ago

# Question about household electricity and circuit breaker?

A common household circuit can carry 20 amps safely. Will the circuit breaker shut-off if four 120-Watt lamps, a 340-Watt television, a 160-Watt VCR, a 700-Watt popcorn machine, and an 900-Watt curling-iron are all being used at once?

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• Anonymous
2 weeks ago

My answer is for a 120 volt "common household circuit" in the USA.

First of all, the most common household circuit is 15 amps.  That's 1800 watts.  I use the 80% rule for everything.  That's 1440 continuous watts maximum.

A 20 amp household circuit has a different receptacle.  That's 2400 watts.  Using the 80% rule, that's 1920 continuous watts maximum.

Your situation would use 2580 watts.

So the answer is clearly that it's an overload for either size circuit.  The circuit breaker should trip for either circuit.

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• add up the watts to get 2580 watts

Assuming this is the US, I = P/V

nominal voltage varies between 110 and 120 VAC, take worse case, 110 volts, and I = 2580/110 = 23 amps. Yes, the breaker would pop

Not in North America?

I = 2580/220 volts = 11 amps, No.

• Most of this load is resistive in nature and thus the wattage goes down as the voltage goes down.

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• If the issue is a 120V circuit, Yes the total is 21.5A and the circuit breaker will probably trip.

If it is on a 230V system, No it probably will not trip.

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• Probably using the equivalent of a multiple point radial circuit. Think US code says a maximum of 2 double socket outlets on a 20 amp circuit especially in kitchens. There is also a maximum length for a given cable guage size. For the total load current add up the total wattage of the connected appliances then divide by the supply voltage.

Ptotal = V x I

I = Ptotal / V

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• Here in europe, 20 amps times 230 Volts means 4,600 Watt

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• Under steady-state conditions a 20 amp breaker should do the job without tripping. However, you must realize that most of the devices you mention have a significantly higher current draw during startup or during warm up. If you go with this setup, you may experience periodic trips of the breaker when you turn on a device with all of the others connected or if you turn on two at the same time.

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• You haven't provided the voltage.120?,125?

4*120W + 340W +160W + 700W + 900W = 2580W

2580W/20A = 129V

YES, unless the circuit voltage is > 129V

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• NO, IT WORKS WELL.....

BECAUSE 230V*20A = 4600W   ABLE TO HOLD SINCE TOTAL CONSUME WATTAGE IS 2580W

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• You are mistaken about some things. 20 AMPS is a lot of current and it will cause the temperature of the wire to rise.  Wattage is volts times amps to if you take all the wattages and add them you get 3400 Watts. Divide that by 120 and you get 28.3 AMPS and that would trip the circuit breaker,

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• add up the watts to get 2580 watts

Assuming this is the US, I = P/V

nominal voltage varies between 110 and 120 VAC, take worse case, 110 volts, and I = 2580/110 = 23 amps. Yes, the breaker would pop

Not in North America?

I = 2580/220 volts = 11 amps, No.

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