Will it trip the breaker?

[Strathead]

You have to answer the question; Why did some think immediately that the current would drop in half as the voltage doubling? I haven't seen anybody here answer that question. I've tried to explain that to no avail.

We can't get in the mind of someone else, but if I have a commercial toaster, and the nameplate states voltage, 120 or 240 (and they do exist). Then hooking it up to 240 volts WILL halve the amperage. BUT it requires the wires in the pecker head to be made up differently for the different voltages. Perhaps there are some who went down that road.

You can dispute it until the cows come home, but it is not a good question because there are too many variables that allow for different answers and/or require clarification.

It would be like me asking you what the voltage of earth is. Be careful, because it is quite unlikely (but possible) that it is zero. It is not a question that has an answer. Any more than how far away is San Francisco. Unless your answer is 2,748 miles, then it isn't from where I meant or using the route I intended, but i failed to give you that parameter, so how could you answer.

 

[Strathead]

You get the prize! This is exactly why guys that have been in the field get this wrong. You hit it on the head! They think so quick and say what they see on a daily basis. Transformers have this too. Voltage goes up on the primary, but the current goes down. It's not about math at this point, but how they are thinking without really thinking the problem through. I am so happy finally see's what I have been trying to articulate for four days!

She watched all of Mike Holts classes on DVD. I guess she could read n OHMS wheel just like the rest of us. I would not trust her to hook up a 3-way! Lol But, she passed it and in the nineties. That four-year degree from Florida State had some value after all! Go Miami Hurricanes!

So, when guys would come to me and say they couldn't pass their masters class, I would show them her EC Unlimited License. And say, you have no excuse but to study more and take the test. I always had a full set of Mike Holts DVDs at the shop for their use. I also use to pay for all the apprentices that went to school. But, I would tell them, if they quit, they would have to refund the money to me. A bad way to force them but it helped keep them in class.

But they didn't necessarily get it wrong. How many times do actual geniuses on this forum need to tell you there is more than one answer to your question before you concede that right and wrong are relative to variables YOU failed to clarify?

 

[K8MHZ]

There is this to deal with:

• When you push down on the handle, the plastic bar presses against the contacts and applies power to the circuit board.
• 120-volt power runs directly through the contacts to the nichrome wires to start toasting the bread.
• A simple circuit made up of transistors, resistors and capacitors turns on and supplies power to the electromagnet.
• The electromagnet attracts the piece of metal on the handle, holding the bread in the toaster.
• The simple circuit acts as a timer. A capacitor charges through a resistor, and when it reaches a certain voltage it cuts off the power to the electromagnet. The spring immediately pulls the two slices of bread up.
• In the process, the plastic bar rises and cuts off power to the toaster.

So, in the real world, a 120 volt toaster would not hold itself down long enough to heat up the elements, and the OCPD would not open. I challenge anyone to disprove this.

The actual question asked:

Will it blow the fuse?

The answer is no, and only an experiment will prove or disprove my answer. Only accepting yes as an answer is accepting a wrong answer, which can be proven, although I am not sure how safely.....

 

[480sparky]

Another HUGE ambiguity right outta the gate:

The thread is titled "Will it trip the breaker?" and ends with "Will it blow the fuse?".

 

[ggunn]

Another HUGE ambiguity right outta the gate:

The thread is titled "Will it trip the breaker?" and ends with "Will it blow the fuse?".

Ah, but will it burn your toast?

 

[480sparky]

Ah, but will it burn your toast?

Is coffee included?

 

[K8MHZ]

Ah, but will it burn your toast?

No, it will just flame broil it.

 

[motormuff]

Yes it will trip the breaker but the toaster will be toasted

Yes it will trip the breaker but the toaster will be toasted

Yes it will most likely trip the breaker if the element doesn't burn open first and not ground out. Use ohms law and you will see that the wattage varies with the square of the voltage. 120 to 240 is double or 2. 2 squared is 4. 4 times a 1000 watt element is a 4000 watt heater. Which is 16.66 amps at 240. The breaker will eventually open but my money is on the toaster burning up first.

 

[lu#26]

Your're Fine

Your're Fine

I know this is an easy one for most, but it can hang up even the most seasoned electrician that has a bias in his thinking. When you see the problem, what's the first answer that comes to mind?

Ok, we have a 110-volt toaster, 1000 watt, on a 15 amp circuit.

The new apprentice (JW would never do this) lol, takes off the neutral and wires it to 220 volts. Still, 15 amp circuits.

Will it blow the fuse?

That's about 10-amps if all else on the circuit is good.

 

[kwired]

That's about 10-amps if all else on the circuit is good.

:happysad::happysad:

If 1000 watts @ 120 volts then it is 8.33 amps, if resistance remains reasonably constant, doubling the volts will double the amps, but will quadruple watts.

 

[ggunn]

:happysad::happysad:

If 1000 watts @ 120 volts then it is 8.33 amps, if resistance remains reasonably constant, doubling the volts will double the amps, but will quadruple watts.

But as we discussed in the Ohm's Law thread, the resistance of a conductor varies with temperature; with the voltage doubled the temperature will almost certainly be a lot higher.

 

[kwired]

But as we discussed in the Ohm's Law thread, the resistance of a conductor varies with temperature; with the voltage doubled the temperature will almost certainly be a lot higher.

Correct, that is why I said if resistance remained reasonably constant. with roughly 4 times the watts before factoring in actual resistance it will definitely be hotter. If resistance rises it won't be as much current and watts will also be less than 4x, if resistance lowers, it will be more current and more watts - and even more likely that it won't take it for long before part of element burns open either, it kind of becomes a race between overcurrent device tripping and what point does the element effectively become an open fuse.

 

[lu#26]

Your're Fine

Your're Fine

He said 110v with a 1000w toaster. That's 9.09 amps.
I said, "That's about 10-amps if all else on the circuit is good".
If you want to talk about every worst-case scenario, then I'd suggest that no one stick a fork in the toaster and perhaps the resistance may be O.K.

 

[lu#26]

Your're Fine

Your're Fine

...taking the neutral off the circuit is a non-starter - do that and, of course MAJOR toubles will occur - I agree, but who in their right mind would do that and for what reason? It makes no sense whatsoever.

 

[LarryFine]

Your're Fine

Yes, I am.

 

[roger]

He said 110v with a 1000w toaster. That's 9.09 amps.
I said, "That's about 10-amps if all else on the circuit is good".
If you want to talk about every worst-case scenario, then I'd suggest that no one stick a fork in the toaster and perhaps the resistance may be O.K.

Go back and read it again, the 110V is not the question.

...taking the neutral off the circuit is a non-starter - do that and, of course MAJOR toubles will occur - whatsoever.

In the question the neutral would not be removed, it would be changed to a hot conductor.

I agree, but who in their right mind would do that and for what reason? It makes no sense

It's a test question scenario however, things get wired wrong everyday so it could happen.

Roger

 

[kwired]

He said 110v with a 1000w toaster. That's 9.09 amps.
I said, "That's about 10-amps if all else on the circuit is good".
If you want to talk about every worst-case scenario, then I'd suggest that no one stick a fork in the toaster and perhaps the resistance may be O.K.

I considered the fact: 110 volts and 1000w = 9.09 amps when I replied. How much precision is in "about"? 5% - you are outside that range, 10% you are in range but getting close to the outer limit.

Resistance of element is likely going to change some when it heats up, but just assuming true linear resistance, doubling volts across a fixed resistance yields double current and quadruple the wattage.

 

[mivey]

[/COLOR]
Yes, I am.

so kind

 

[petersonra]

I know this is an easy one for most, but it can hang up even the most seasoned electrician that has a bias in his thinking. When you see the problem, what's the first answer that comes to mind?

Ok, we have a 110-volt toaster, 1000 watt, on a 15 amp circuit.

The new apprentice (JW would never do this) lol, takes off the neutral and wires it to 220 volts. Still, 15 amp circuits.

Will it blow the fuse?

Probably not. The resistive elements in the toaster probably fail before the fuse blows.

 

[Gary11734]

Probably not. The resistive elements in the toaster probably fail before the fuse blows.

Somewhere in this thread, I said the fuse would be considered the weakest link of the circuit...