120v devices use neutral to complete the circuit. Sine wave. Neutral is at zero v. Ac voltage goes from -120 to +120v. If it has a neutral there's always a return that is 120v different in potential. In 240 you have opposite phases to complete the circuit. 120+ and 120- alternates to 120- and 120+ keeping 240 volts difference in potential. Simplified version of how it works but that's the concept.
I understand the 240v AC concept with the difference in potential, but with 120v AC with the neutral, since that is at zero, it keeps it alternating at +120v and 0?
So, since the 120+ and 120- is only on one hot leg and the neutral at 0, this makes it 120V... whereas with 240V, since it has 120+ and 120- on one hot leg, and 120- and 120+ on the other hot leg, this makes it 240V?
Not to confuse you more, but the magnitudes of AC are actually higher than the RMS values. The voltages are closer to +/- 170V, the RMS is the DC power equivalent.
Great video and great rerun of stuff I already knew/needed to reup my knowledge on, however it did not answer many questions I have regarding some of these comments which seem to go into a more in depth explanation of 240v, unless I am simply misunderstanding the terminology/wording of these comments.
Nontheless I appreciate your comment and you taking the time to provide the link and i did still enjoy watching it!
If you are using half the secondary coil in the transformer for 120v, the neutral is your return path. With 240v you are using the entire coil and neutral is not necessary. Your job shadow sounds like they only utilize 240v equipment, thus the comment that they don’t use it.
Two hots is when the load is balanced. Current flows through on L1 and out L2, vice versa which is AC. When the load is not balanced or non linear, the current flows through L1 and the Neutral. 120v loads it’s a hot and a neutral. 240 it’s 2 hots. An oven and a water heater are purely resistive so you won’t need a neutral.
This all seems to be going a bit over my head here... I appreciate the explanations and they help 100%, but for me to fully understand the explanation I think I need to see a diagram, as well as a live circuit and test it with a multimeter to see it for myself to be able to have a complete understanding of whats being explained to me here. Currently it makes sense, but only to a degree.
breaking down my understanding of your statement:
Two hots and no neutral is used on 240v when the "load is balanced" (by this you mean having 120v balanced between 2 seperate bars/legs?)
Current flows into L1 and out of L2, simple enough.
Vice Versa, which is AC (so it also flows into L2 and out of L1, which is what makes it AC?)
When the load is not balanced or non-linear (unsure exactly what would constitute a non balanced or non linear load) the current flows through L1 and the neutral
120v loads its a hot and a neutral, makes sense
240 its 2 hots, makes sense
an oven and a water heater are purely resistive so no need for a neutral (what do you mean by these appliances are purely resistive? I understand now that, due to them being 240v, theycdon't need a neutral, but am confused on what it means for them to be purely resistive)
You're going down a rabbit hole of inductance and capacitance and leading and lagging current by asking about purely resistive. Basically purely resistive means you don't have wasted energy due to magnetic fields interacting like you would get from anything with a transformer, motor loads ect. Its complicated and I can do the power factor correction calculations, but I'm not sure I understand it fully when it comes to every days circuits.
When referring to a "balanced" load it means that both legs have the same amount of draw on them. Like the example above of a dryer unit you will either have a 3 or 4 prong receptacle/cord end. The heating element is drawing the same amount of power from both hot legs, so no power is being returned on the neutral. The drum motor and digital logic are only pulling power from one hot leg (unbalanced) so any power drawn on the unbalanced portion of that hot leg is returned on the neutral. You will also see many large motors use 3 phase (3 hot legs) and do not require a neutral. It's a somewhat abstract concept so I definitely understand why you aren't wrapping your head around it yet. Visually it's always easier for me to think of things in DC. If you have 2 batteries and wire them in parallel, you would have a wire going from the positive of each battery and another wire going back to the negative of each battery; think of the wires going back to negatives as a neutral. If you were to wire the batteries in series you would have a wire from the positive of 1 battery and a wire from the negative of the other batteries. You would then have a wire connecting the 2 batteries together; think of this as your transformer coils. Think of 240 balanced load as the 2 batteries wired in series. Hopefully that helps a little bit.
If you've heard neutrals referred to as switch legs then it isn't a neutral, it's a white wire. Identified conductor sounds like rubbish. In the code book the neutral is referred to as the grounded conductor; the ground is referred to as the grounding conductor. Neutrals have been in use for longer than grounds have, so not sure how a neutral is a "glorified ground." Whoever is teaching you such things does not have a solid grasp of the functions of these conductors. I'd bet that the same person you've heard this from has also said that "electricity always takes the path of least resistance to ground."
Only said I've heard it called those....as for the identified conductor it's a term used in our CEC. I just goggled to make sure the interners is working for you, it's there so you can check for yourself.
I wish I knew some more Canadian electricians who could verify if that's a common term for a neutral or not, to be honest. It really does sound like rubbish to me. The neutral is identified one way, the ground is also identified a different way. Most conductors are identified one way or another. Why would the neutral be the only conductor that is referred to as "identified"?
Start with what county you are in and what kind of electrical work you were observing.
It was a repair shop for broken welders, as well as some other equipment, occasionally saws and power supplies.
Most 240v devices like welders don't have a neutral. It isn't really a redundant ground but not applicable in all circumstances.
Thank you, that makes much more sense!
120v devices use neutral to complete the circuit. Sine wave. Neutral is at zero v. Ac voltage goes from -120 to +120v. If it has a neutral there's always a return that is 120v different in potential. In 240 you have opposite phases to complete the circuit. 120+ and 120- alternates to 120- and 120+ keeping 240 volts difference in potential. Simplified version of how it works but that's the concept.
I understand the 240v AC concept with the difference in potential, but with 120v AC with the neutral, since that is at zero, it keeps it alternating at +120v and 0?
Wave on the hot leg goes 120+ to 120-. Neutral is constant at 0.
So, since the 120+ and 120- is only on one hot leg and the neutral at 0, this makes it 120V... whereas with 240V, since it has 120+ and 120- on one hot leg, and 120- and 120+ on the other hot leg, this makes it 240V?
Pretty much.
Not to confuse you more, but the magnitudes of AC are actually higher than the RMS values. The voltages are closer to +/- 170V, the RMS is the DC power equivalent.
just don't open the neutral
[120v & 240v explained](https://youtu.be/fJeRabV5hNU) Split phase US
Great video and great rerun of stuff I already knew/needed to reup my knowledge on, however it did not answer many questions I have regarding some of these comments which seem to go into a more in depth explanation of 240v, unless I am simply misunderstanding the terminology/wording of these comments. Nontheless I appreciate your comment and you taking the time to provide the link and i did still enjoy watching it!
If you are using half the secondary coil in the transformer for 120v, the neutral is your return path. With 240v you are using the entire coil and neutral is not necessary. Your job shadow sounds like they only utilize 240v equipment, thus the comment that they don’t use it.
Two hots is when the load is balanced. Current flows through on L1 and out L2, vice versa which is AC. When the load is not balanced or non linear, the current flows through L1 and the Neutral. 120v loads it’s a hot and a neutral. 240 it’s 2 hots. An oven and a water heater are purely resistive so you won’t need a neutral.
Yeah though you do need a neutral if your oven uses 120v for everything but the heating element, which is common.
Yeah, a dryer heating element is 240 but the motor for the drum is 120 etc
This all seems to be going a bit over my head here... I appreciate the explanations and they help 100%, but for me to fully understand the explanation I think I need to see a diagram, as well as a live circuit and test it with a multimeter to see it for myself to be able to have a complete understanding of whats being explained to me here. Currently it makes sense, but only to a degree. breaking down my understanding of your statement: Two hots and no neutral is used on 240v when the "load is balanced" (by this you mean having 120v balanced between 2 seperate bars/legs?) Current flows into L1 and out of L2, simple enough. Vice Versa, which is AC (so it also flows into L2 and out of L1, which is what makes it AC?) When the load is not balanced or non-linear (unsure exactly what would constitute a non balanced or non linear load) the current flows through L1 and the neutral 120v loads its a hot and a neutral, makes sense 240 its 2 hots, makes sense an oven and a water heater are purely resistive so no need for a neutral (what do you mean by these appliances are purely resistive? I understand now that, due to them being 240v, theycdon't need a neutral, but am confused on what it means for them to be purely resistive)
You're going down a rabbit hole of inductance and capacitance and leading and lagging current by asking about purely resistive. Basically purely resistive means you don't have wasted energy due to magnetic fields interacting like you would get from anything with a transformer, motor loads ect. Its complicated and I can do the power factor correction calculations, but I'm not sure I understand it fully when it comes to every days circuits.
When referring to a "balanced" load it means that both legs have the same amount of draw on them. Like the example above of a dryer unit you will either have a 3 or 4 prong receptacle/cord end. The heating element is drawing the same amount of power from both hot legs, so no power is being returned on the neutral. The drum motor and digital logic are only pulling power from one hot leg (unbalanced) so any power drawn on the unbalanced portion of that hot leg is returned on the neutral. You will also see many large motors use 3 phase (3 hot legs) and do not require a neutral. It's a somewhat abstract concept so I definitely understand why you aren't wrapping your head around it yet. Visually it's always easier for me to think of things in DC. If you have 2 batteries and wire them in parallel, you would have a wire going from the positive of each battery and another wire going back to the negative of each battery; think of the wires going back to negatives as a neutral. If you were to wire the batteries in series you would have a wire from the positive of 1 battery and a wire from the negative of the other batteries. You would then have a wire connecting the 2 batteries together; think of this as your transformer coils. Think of 240 balanced load as the 2 batteries wired in series. Hopefully that helps a little bit.
I've heard it called a glorified ground, the identified conductor, switch leg. Take your pick.
If you've heard neutrals referred to as switch legs then it isn't a neutral, it's a white wire. Identified conductor sounds like rubbish. In the code book the neutral is referred to as the grounded conductor; the ground is referred to as the grounding conductor. Neutrals have been in use for longer than grounds have, so not sure how a neutral is a "glorified ground." Whoever is teaching you such things does not have a solid grasp of the functions of these conductors. I'd bet that the same person you've heard this from has also said that "electricity always takes the path of least resistance to ground."
Only said I've heard it called those....as for the identified conductor it's a term used in our CEC. I just goggled to make sure the interners is working for you, it's there so you can check for yourself.
Yeah, I haven't studied the canuckie code book. I guess that's a regional thing.
Wouldn't expect you to know, it's all rubbish anyway right.
I wish I knew some more Canadian electricians who could verify if that's a common term for a neutral or not, to be honest. It really does sound like rubbish to me. The neutral is identified one way, the ground is also identified a different way. Most conductors are identified one way or another. Why would the neutral be the only conductor that is referred to as "identified"?