110 vac vs 115 vac vs 120 vac

[BB_TX]

Forgive me. But this is something as a retired electrical engineer that for some reason bugs me, and I always seem to feel the need to correct, or at least clarify. Although I rarely do.

People often mention plugging into a 110 outlet. And I think in general most people understand they are meaning a standard home type 15 amp or 20 amp outlet. In reality it is 120 vac. But a 30 amp outlet is also 120 vac. And, for all practical purposes, when you plug into a 50 amp outlet you are still supplying 120 vac to your trailer, just happens to be two separate legs of it. And that is in spite of the fact that there is 240 vac (not 220 vac) measured between the two hots.

110 vac was the original voltage level Edison chose for his light bulb and was used as the standard for many years. And that became ingrained as the term used to describe an electrical outlet. But that was raised to 115 vac in the 1930’s and was the standard voltage until it was raised again in 1984 to 120 vac, the current standard. Utilities are required to supply 120 vac +/- 5%. But, although inaccurate, the 110 vac term lives on.

Would be better to say I plugged into a 15 amp, or a 20 amp, or a 30 amp, or a 50 amp

Sorry. My little engineer brain at work again.

https://www.quora.com/Is-the-power-s...-240-or-235VAC

[AZ Traveler]

Should we start using 114-126 vac to cover the 5%?

[masterdrago]

Originally Posted by BB_TX

Would be better to say I plugged into a 15 amp, or a 20 amp, or a 30 amp, or a 50 amp

https://www.quora.com/Is-the-power-s...-240-or-235VAC

I like 120. Pretty much what the meter says.

[BB_TX]

Originally Posted by masterdrago

I like 120. Pretty much what the meter says.

Certainly more accurate. But when someone ask if it is ok to plug into a 120 outlet without any further info my first thought is always is it 15 amp or 20 amp and what do you intend to do. You can run an A/C unit on 20 amp to cool the trailer, but not likely on 15 amp. But maybe I tend to over think things.

[Jamesb]

If you will notice, not in an older campground where the wiring is inadequate, that the voltages are surpassing 120 volts. Working in the utility side of life for 20+ years, and with the industrial loads are gone and disappearing, the voltages continue to climb. Not a bad thing though. At least it helps with the older loaded campgrounds. High voltage is way better than low voltage. On a lot of the East coast, we see 121-126 as normal. Boils water on the electric stove faster ��

[Mikendebbie]

I asked the question about a 110V outlet in another thread. I should have said...
“Is is ok to plug into one of these?”

[mlh]

What Bill says I think is what I do when plug my generator in an outside 30 amp 220 or is that 240 volt plug in using two 120 plugs. One for each side of my breaker box.
Bill if this is a right PLEASE say so. I like being wrong. I learn something every time.
Lynwood

[BB_TX]

Originally Posted by Mikendebbie

I asked the question about a 110V outlet in another thread. I should have said...
“Is is ok to plug into one of these?”

It is a term that is still often used and frequently appears on RV forums and the Montana Owners Facebook page. Old habits, and old terminology, did hard.

[BB_TX]

Originally Posted by mlh

What Bill says I think is what I do when plug my generator in an outside 30 amp 220 or is that 240 volt plug in using two 120 plugs. One for each side of my breaker box.
Bill if this is a right PLEASE say so. I like being wrong. I learn something every time.
Lynwood

There is no 220 vac any more. At last not in the normal power distribution system. It is 120 vac or a multiple of it, 240, 480.

As for a 30 amp outlet, an RV 30 amp outlet is 120 vac. A dryer outlet or welder outlet may be 240 vac. A 50 amp RV outlet is 240 vac providing two 120 vac legs for the RV. Some high end RVs do have some 240 vac appliances. But no stock Montana has any 240 vac appliances.

[Dave W]

It's all semantics
If you talk to me about 110VAC or 120VAC, I'll know exactly what you mean. 220 vs 240 = same. I think I use 120VAC, never 115 when I'm discussing a low household/RV voltage but I know that I use 220VAC for the higher and do know that it's wrong. And those appliances that use that higher voltage usually say 220 on the tag. My table saw forinstance says 110/220VAC, depending on how it's wired in its terminal box



In my work life, we had EE and ME field engineering staff. If I needed an EE, I went to that groups manager.If he needed an ME, he came to my group. We mechanicals worked with things we could see, the EEs. well I never saw an electron, but maybe they did.

[mlh]

Bill if we saw a chart of our utility power electric power it would be a nice curved line up and back down. A cheap inverter this line is squared off straight up straight across the top and back down. When we speak of dirty powder from a generator is this what it is or is it something different?
While we have you on a roll I’m going to pick your brain.
Thanks Lynwood

[psomers]

Pretty sure Edison’s light bulb was DC. Westinghouse was the one that used AC and was the adapted standard.
Know the voltage is 120 AC but I often refer it vas 110. Getting too old to make changes.

[BB_TX]

Originally Posted by mlh

Bill if we saw a chart of our utility power electric power it would be a nice curved line up and back down. A cheap inverter this line is squared off straight up straight across the top and back down. When we speak of dirty powder from a generator is this what it is or is it something different?
While we have you on a roll I’m going to pick your brain.
Thanks Lynwood

Now you are getting into something I am not too familiar with. I know square wave power will work for resistive loads and some motors. But it can damage other more sensitive devices. Sine wave is a much better option.

I knew this post was going to generate a lot of discussion. But what else is there to do with the weather too cold to get out and otherwise occupy yourself?

But while we are having fun, lets talk about current flow. We all understand that current flow is those little electrons flowing thru a wire. And that is true. And we all think of current flow as those electrons flowing from the positive terminal to the negative terminal. And that is false.

Atoms (in this case making up the metal wire) are made up of a positive charged center composed of protons and neutrons, and negatively charged electrons orbiting around that center (something like moons around a planet).

Electrons have a negative charge and actually flow from the negative power terminal to the positive power terminal! Holes flow from the positive terminal to the negative terminal. What is a "hole"? When a voltage is applied to a circuit, those little electrons get excited, start jiggling, and electrons in the outer layer of an atom (those with a weaker magnetic attraction to the positive core) will break free, leaving a hole in that atom structure. That hole leaves an opening for an electron from a nearby atom to jump from its atom to that atom. An electron needs a nearby hole to be able to move. That action cascades until lots of those little guys start jumping from atom to atom ending up traveling from the negative power terminal to the positive power terminal and creating current flow. And since the electrons are traveling from negative to positive, the holes left behind are traveling from positive to negative. One is called electron flow, and the other called hole flow. Hole flow is what is thought of as conventional current flow since it flows from positive to negative. Doesn't really matter unless you are into semi conductor theory. And even I am not in that deep.
Now I will go back and hide.

[CADman_KS]

Originally Posted by BB_TX

...

110 vac was the original voltage level Edison chose for his light bulb and was used as the standard for many years. And that became ingrained as the term used to describe an electrical outlet. But that was raised to 115 vac in the 1930’s and was the standard voltage until it was raised again in 1984 to 120 vac, the current standard. Utilities are required to supply 120 vac +/- 5%. But, although inaccurate, the 110 vac term lives on.

...

I never knew that there was a "history" of using 110V-115V-120V. I never really knew why it is often referred to it as 110V.

It appears that accounts vary on when we went to 120V, as Wikipedia lists it as 1967. Who knows.

https://en.wikipedia.org/wiki/Mains_electricity

At any rate, thanks for an insight into history. I learned something today!

[jeffba]

So when someone says their AC is not working, should we ask if it is 110, 115, 120 or air conditioning?

Asking for a friend.

[CADman_KS]

Originally Posted by jeffba

So when someone says their AC is not working, should we ask if it is 110, 115, 120 or air conditioning?

Asking for a friend.

LOL. I dont care who you are, that's funny!!!

On a serious note, this is why I have an EMS that I can see what our voltage is. At our local campground, I have seen 120 down to 115, so either answer must be correct!!!

[StageCoachDriver]

I fell the same way when people use the term "accident" for a motor vehicle collision. Accident says no one is at fault and is seldom used by policemen when investigating a traffic collision.

Regarding 120V wall outlet voltage, it's really 120 V RMS, but it's actually approx 340V peak-to-peak.

[twindman]

Originally Posted by CADman_KS

LOL. I dont care who you are, that's funny!!!

On a serious note, this is why I have an EMS that I can see what our voltage is. At our local campground, I have seen 120 down to 115, so either answer must be correct!!!

I also have (and love) my EMS. I was at the last end site in a campground in Kansas last summer. It was very hot outside. The voltage readout was around 115 I think until I turned something on like the water heater or A/C. Then it would drop to 108. And soon after the EMS would shut down. Rinse and repeat until it cooled down a little bit. I had to shut almost everything off except the A/C to stay cool.
After my first of 2nd summer in the midwest when the voltage dropped and I burned out my A/C, I got a surge protecter/EMS. I won't leave home without it!!!

[Jamesb]

Originally Posted by StageCoachDriver

I fell the same way when people use the term "accident" for a motor vehicle collision. Accident says no one is at fault and is seldom used by policemen when investigating a traffic collision.

Regarding 120V wall outlet voltage, it's really 120 V RMS, but it's actually approx 340V peak-to-peak.

Dang 340v peak to peak? I hope you not in the US.

[RETCHIEF]

Originally Posted by BB_TX

Forgive me. But this is something as a retired electrical engineer that for some reason bugs me, and I always seem to feel the need to correct, or at least clarify. Although I rarely do.

People often mention plugging into a 110 outlet. And I think in general most people understand they are meaning a standard home type 15 amp or 20 amp outlet. In reality it is 120 vac. But a 30 amp outlet is also 120 vac. And, for all practical purposes, when you plug into a 50 amp outlet you are still supplying 120 vac to your trailer, just happens to be two separate legs of it. And that is in spite of the fact that there is 240 vac (not 220 vac) measured between the two hots.

110 vac was the original voltage level Edison chose for his light bulb and was used as the standard for many years. And that became ingrained as the term used to describe an electrical outlet. But that was raised to 115 vac in the 1930’s and was the standard voltage until it was raised again in 1984 to 120 vac, the current standard. Utilities are required to supply 120 vac +/- 5%. But, although inaccurate, the 110 vac term lives on.

Would be better to say I plugged into a 15 amp, or a 20 amp, or a 30 amp, or a 50 amp

Sorry. My little engineer brain at work again.

https://www.quora.com/Is-the-power-s...-240-or-235VAC

I spent my first USAF career in Missile Electronics Instrumentation R&D. I have had this discussion often with all levels of folks. I ran the Technical School for my career field and had each instructor measure the AC at the wall and write it down. It helped maintain the same standard for all.