220 vs 240 outlet questions

[moparkid440]

hey Everyone
I have a question understanding the difference between 220 volt outlets and 240 volt outlets. I saw a video online of someone adding, as the video describes, 220 volt outlets to their shop. He opens the panel, and obviously by means of a double breaker, connects both hot poles in the panel, each having 120 volts. He wires the outlet and ends up getting 240 volts at the outlet he installs (120 + 120= 240). So then why is he referring to that outlet as a 220 volt outlet? This question is not just from this video by the way but everywhere I've researched this but can't get an explanation why. Are 220and 240 volts the same? why call it a 220 volt outlet when you have 240 volts there?

The reason I ask this is because I have a 240 volt outlet (with a 30 Amp breaker) installed in my garage (i just tested it with a meter and I actually get around 250 volts). I am installing an Automotive lift in my garage and the specs for the power unit specifically say its powered by 220 Volt (single phase) 60 Hz (+/- 5%, so 209-231 volts).

1) Will the outlet in my garage work with this power supply or will I have to swap out outlets in my garage to a specific one for 220V?

2) The outlet Installed in my garage has 3 prongs: 2 hot wires from the breaker and 1 neutral wire. Should the metal outlet box, housing the outlet, be grounded to the ground side in the panel box? (wire going from ground bar in panel box to ground screw inside the box) (i didn't install this outlet, but the green ground wire is not connected in the panel box but just in there with a **** connector on the end). I've always grounded 120 in that way but wasn't sure if 240 is different, as thebreason the green ground is disconnected. Thanks everyone

 

[pattenp]

220V was the standard voltage supplied by the power companies years ago, 240V is the standard today. People who say 110/ 220V are stuck in the past. Manuals in many cases still refer to 220V instead of 240V so don't worry about it.
Metal box should be grounded. Sounds like you have an old ungrounded type outlet and should be changed. What is the nema # on the outlet?

 

[rlitman]

Just to be clear, there is no such thing as either.

The residential electrical grid in the US is for the most part nominally 120/240V 60Hz, with odd exceptions in small places.

OUTLETS are rated 125/250V. Wire is rated 300V or 600V. Motors have their own voltage ratings...

 

[alfredeneuman]

This question is not just from this video by the way but everywhere I've researched this but can't get an explanation why. Are 220and 240 volts the same? why call it a 220 volt outlet when you have 240 volts there?

There is no such thing as 220 in the US, it is the wrong wording (but plenty of folks call it 220 nonetheless)
All 208 through 240 receptacles are rated at 250V, just as 120V recps. are rated at 125V.
110 DC was Edison's original voltage and it went nowhere because of Westinghouse's (and Tesla's) AC was able to be transformed to higher and lower voltage.

 

[Showkey]

Plenty of brands or manufacturers split the difference on the box or product label with:

115/230volts Vs 110/220 vs 120/240

Maybe the best way to say, it’s a nominal stated value........

 

[rlitman]

...110 DC was Edison's original voltage and it went nowhere because of Westinghouse's (and Tesla's) AC was able to be transformed to higher and lower voltage.

That's a kind of funny thing. I actually knew of a site in NYC where the power company was required to provide unmetered 110VDC in perpetuity due to a 19th century contract. According to Wikipedia, the last DC service was ended in 2007, with any remaining customers being converted to on-site rectifiers. I wonder what happened there...

And in the high voltage transmission world, DC is now king, with high power solid state electronics making many of Tesla's innovations outmoded.

 

[rlitman]

Plenty of brands split the difference on the box label with:

115/230volts Vs 110/220 vs 120/240

Nope. Remember that I said about motors? They're rated on a different voltage scale.

 

[yatg]

That's a kind of funny thing. I actually knew of a site in NYC where the power company was required to provide unmetered 110VDC in perpetuity due to a 19th century contract. According to Wikipedia, the last DC service was ended in 2007, with any remaining customers being converted to on-site rectifiers. I wonder what happened there...

More info, but doesn't say anything about the original contract terms.

https://cityroom.blogs.nytimes.com/2007/11/14/off-goes-the-power-current-started-by-thomas-edison/

 

[Showkey]

Nope. Remember that I said about motors? They're rated on a different voltage scale.

The labeling is all over the place and not consistent with any logic.
There is no motor in my Lincoln welder or my coffee pot......it says 115/230 volt.........

Get over it...........it’s nominal, as in:

3.
(of a quantity or dimension, especially of manufactured articles) stated or expressed but not necessarily corresponding exactly to the real value.

http://www.electrical101.com/electrical-voltages.html


The best label is on SONOS speakers 100/240volts

 

[wyliesdiesels]

Sounds like you have an old dryer outlet.

A 240v motor does not need a neutral. Does this outlet connect to a subpanel?

Also, 250v is getting a bit high for nominal voltage. I would call the power company.

 

[rlitman]

More info, but doesn't say anything about the original contract terms.

https://cityroom.blogs.nytimes.com/2007/11/14/off-goes-the-power-current-started-by-thomas-edison/

Its not loading for me (edit: this time it came up), but I saw the handwritten contract and ledgers from the day in the archives. It was quite the sight. This particular one exception was not simply a service for a customer, but was something gifted by Edison for services rendered. Long story, but I know that most sites were simply Con Ed customers in the vicinity of substations, so they had different considerations. Many of these customers still have direct steam service too. The site I was familiar with used steam to power their air conditioning for example.

Oh, and that article is wrong. The NYC subway does not use DC. They use 25Hz AC. An entirely weirder system.

...Get over it...........it’s nominal, as in...

Exactly, however the people who set the nominal numbers are different in each use case, with each starting from different historical sources. Kind of like how CTS and IPS nominal pipe schedules are similar, but are not the same.

 

[Norcal]

Motors, air conditioning, and welding equipment are rated 115/200/230/265/460 Volts, lighting, & electric resistance heating equipment are 120/208/240/277/480 volts which is also the nominal supply voltages. I did leave Canadian voltages of 347V, and 575/600V out.


Cheap ChiCom junk like Grizzly & others will be sold as 110/220V.

 

[Innovate1]

It's mostly people just getting sloppy with their words. People may say 110, 115, 120 and all mean the same thing. In most cases it may not be technically correct but as Showkey pointed out it is just convention and doesn't state the exact voltage.

If a device actually states a voltage range or tolerance then best to stay within that range. Most things can tolerate +/-10% line voltage. 5% is pretty tight. You could install a buck/boost transformer if you are worried about it or ask the power company to adjust the tap on your transformer. Hard to say if it really needs to be that close.

I didn't see where you stated what your voltage is by measurement.

220, 221. Whatever it takes....

 

[wyliesdiesels]

It's mostly people just getting sloppy with their words. People may say 110, 115, 120 and all mean the same thing. In most cases it may not be technically correct but as Showkey pointed out it is just convention and doesn't state the exact voltage.

If a device actually states a voltage range or tolerance then best to stay within that range. Most things can tolerate +/-10% line voltage. 5% is pretty tight. You could install a buck/boost transformer if you are worried about it or ask the power company to adjust the tap on your transformer. Hard to say if it really needs to be that close.

[b{I didn't see where you stated what your voltage is by measurement.[/b]

220, 221. Whatever it takes....

250v second paragraph in the OP.

All the PoCos out here do 5% range- 228-252v

 

[TuxThePenguin]

there is no reason to say 220v over 240v (or 230v). No reason to say 110v over 120v (or 115v). But some people just do.

Gotta just accept it because unfortunately it isn't changing.

But the people that say 220 and 110 are simply incorrect.

Historically voltages used to be closer to those, but we're talking quite a long time ago, like the first half of last century.

 

[theoldwizard1]

OUTLETS are rated 125/250V. Wire is rated 300V or 600V.

Years ago, that threw me off until I realized those were "maximum" voltages.

Also years ago, I order some equipment for work that spec'd 240V. Commercial building don't have single phase 240V ! I was freaking out until the installer came, opened up the back and just moved the wire to the 208V connector !

 

[theoldwizard1]

People may say 110, 115, 120 and all mean the same thing.

Years ago, I used to see a lot of "filament" transformers spec'd at 117V input.

 

[nadogail]

You are looking at our habit of not being careful with our words.
As examples we seem to call all facial tissues Kleenex, no mater what is printed on the box; copiers are frequently called Xerox Machines, electric refrigerators were Frigidares, and jeans are referred to as Levies even when they are made by another manufacturer.
Also we commonly refer to all cellophane tape as "Scotch Tape".

We are lazy in our language, and it often leads to confusion.

 

[wyliesdiesels]

Years ago, that threw me off until I realized those were "maximum" voltages.

Also years ago, I order some equipment for work that spec'd 240V. Commercial building don't have single phase 240V! I was freaking out until the installer came, opened up the back and just moved the wire to the 208V connector !

Older commercial buidlings sure do have 240v single phase. Derived from 3phase delta- watch out for the 208v stinger leg

 

[Showkey]

there is no reason to say 220v over 240v (or 230v). No reason to say 110v over 120v (or 115v). But some people just do.

Gotta just accept it because unfortunately it isn't changing.

But the people that say 220 and 110 are simply incorrect.

Historically voltages used to be closer to those, but we're talking quite a long time ago, like the first half of last century.

Probably has an age component to it..........what you grew up with 50 years back.
Maybe if you remember dial phones, party lines and Li5-2167 As valid phone number then 110v or 115v might have stuck in the nomenclature.

 

[theoldwizard1]

Older commercial buidlings sure do have 240v single phase. Derived from 3phase delta- watch out for the 208v stinger leg

What is "older" ? That building was built in the early 80s.

I worked in a different building, that was built in 1920s. It had several major additions over the next 50 years. Luckily, they DID update all of the electrical to 3 phase "Y" as they added on. Very easy to deal with. I hope I never have to deal with delta.

 

[theoldwizard1]

... Li5-2167 As valid phone number ...

Vermont 6 1882 (WOW how can I remember that from over 50 years ago and I need a shopping list if I have more than 2 items?)

 

[u3b3rg33k]

What is "older" ? That building was built in the early 80s.

I worked in a different building, that was built in 1920s. It had several major additions over the next 50 years. Luckily, they DID update all of the electrical to 3 phase "Y" as they added on. Very easy to deal with. I hope I never have to deal with delta.

240V grounded B at my plant. 1600A service.

 

[JordanOH]

IDK why some are so **** about this. If you work on a 120y/208 system you get about 212-215 across 2 legs, definitely not 240.

 

[alfredeneuman]

Vermont 6 1882 (WOW how can I remember that from over 50 years ago and I need a shopping list if I have more than 2 items?)

I have a hard remembering my own phone # these days, but I remember my Grandma's and my own from when I was 3 years old. GEneva32620 and HArrison95428

 

[wyliesdiesels]

What is "older" ? That building was built in the early 80s.

I worked in a different building, that was built in 1920s. It had several major additions over the next 50 years. Luckily, they DID update all of the electrical to 3 phase "Y" as they added on. Very easy to deal with. I hope I never have to deal with delta.

Most PoCos stopped installing 240 Delta in the early 2000s so....

240V grounded B at my plant. 1600A service.

Corner grounded delta is always fun to play with.

IDK why some are so **** about this. If you work on a 120y/208 system you get about 212-215 across 2 legs, definitely not 240.

who said 208Y is 240v?

 

[u3b3rg33k]

Corner grounded delta is always fun to play with.

seems to work fine for us. VFDs don't care. and we get a little more power on the heaters being 240V over 208V.

i don't see why people are so scared of it TBH.

 

[Darkness]

It's a good way to weed out who knows what they are talking about and who doesn't. Just like the lake I live on which only locals can pronounce correctly...I always know if you aren't from around here.

"220" Was never a "standard" in North America. Not 100 years ago, not when Edison and Tesla were fighting, never, ever, ever. 220 is usually within the tolerable voltage range, though, if you only have 220v coming out of your outlet it's either overloaded or your have some other problem.

It gets progressively stupider as you go up. 110 has always been 120. 220 has always been 240. 460v has always been 480v. (Odd people don't try to call it "440") When the voltage keeps doubling your bad terminology gets even worse.

My house has a dedicated 25kva transformer that I barely use...so my 240 is actually around 255.

 

[American Locomotive]

Oh the irony.

Edison's DC system was 110v nominal, and the first AC systems utilized that same voltage too. Edison also had a patented 3-wire system that was 220vDC across the "hots", and 110v to ground. Early split-phase AC systems duplicated that as well. As time went on, line voltage gradually crept up to 115v, 117v and then finally standardized at 120/240v.

There are plenty of old sparkies who call 480v 3 phase "440", because that's what very old equipment used to be rated for.

So you are completely wrong.

It's no different than when someone says they're "filming" a video despite using a digital camera, or a musician saying they're making a new record when their not releasing on vinyl.

 

[nadogail]

We are not guilty of careless speech, but lazy memories.

 

[Darkness]

Edison's DC system was 110v nominal, and the first AC systems utilized that same voltage too. Edison also had a patented 3-wire system that was 220vDC across the "hots", and 110v to ground. Early split-phase AC systems duplicated that as well. As time went on, line voltage gradually crept up to 115v, 117v and then finally standardized at 120/240v.

These were never "standard", and nobody alive today ever saw them so it's not like they were talking about when they were a kid.

There are plenty of old sparkies who call 480v 3 phase "440", because that's what very old equipment used to be rated for.

Again, input and output are two different things with two different tolerances that hopefully overlap somewhere. If your outlets ever put out 440, something is wrong.

It's no different than when someone says they're "filming" a video despite using a digital camera, or a musician saying they're making a new record when their not releasing on vinyl.

Those are also great examples of incorrect word usage. They are however more common, and refer to things people actually used in their recent memory, and actually were standards.

I lived ina time when you could only watch movies on film and you could only buy the newest music on vinyl. I still never lived in a time that 110 or 220 was standard.

Things certainly varied a lot more in the old days, but not the "standard".

 

[JeepJohn62]

hey Everyone
I have a question understanding the difference between 220 volt outlets and 240 volt outlets. I saw a video online of someone adding, as the video describes, 220 volt outlets to their shop. He opens the panel, and obviously by means of a double breaker, connects both hot poles in the panel, each having 120 volts. He wires the outlet and ends up getting 240 volts at the outlet he installs (120 + 120= 240). So then why is he referring to that outlet as a 220 volt outlet? This question is not just from this video by the way but everywhere I've researched this but can't get an explanation why. Are 220and 240 volts the same? why call it a 220 volt outlet when you have 240 volts there?

The reason I ask this is because I have a 240 volt outlet (with a 30 Amp breaker) installed in my garage (i just tested it with a meter and I actually get around 250 volts). I am installing an Automotive lift in my garage and the specs for the power unit specifically say its powered by 220 Volt (single phase) 60 Hz (+/- 5%, so 209-231 volts).

1) Will the outlet in my garage work with this power supply or will I have to swap out outlets in my garage to a specific one for 220V?

2) The outlet Installed in my garage has 3 prongs: 2 hot wires from the breaker and 1 neutral wire. Should the metal outlet box, housing the outlet, be grounded to the ground side in the panel box? (wire going from ground bar in panel box to ground screw inside the box) (i didn't install this outlet, but the green ground wire is not connected in the panel box but just in there with a **** connector on the end). I've always grounded 120 in that way but wasn't sure if 240 is different, as thebreason the green ground is disconnected. Thanks everyone

Lots of interesting history.

Regarding your 240 outlet. I believe the code specifies a green safety ground wire to the outlet, which should also ground the metallic box. There should not be a neutral to that outlet. In your case, it appears you are using the neutral as the safety ground. This is not an acceptable practice.

The service entrance power will be fine for your lift. The voltage varies during the day based on loads.


Sent from my SM-A102U using The Garage Journal mobile app

 

[moparkid440]

No this outlet connects to the main panel.
How could 250v in a 250v outlet be on the high end, especially when each hot wire coming in has 125 (ish) volts? If its a 250v outlet isn't 250 volts normal?

Also, it is a 3 prong outlet. The metal box itself should be grounded to the ground bar inside the panel correct?

 

[Terry D]

Older commercial buidlings sure do have 240v single phase. Derived from 3phase delta- watch out for the 208v stinger leg

We are loaded with 240 and 480 delta here in St Louis. But none of it is center tapped. It is just straight 240 or 480, so we don't have the high leg here. I never even seen it

 

[Lassen Forge]

You're fine - it's all the same. I noticed that a lot of "220" stuff is actually rated 208-240. There is a range of voltages everything runs at... For example -

Our place here is between 117.2 to 118.7 depending on time of day... The feed off the transformer is somewhere between 234 and 237 (nominal). Our 240 volt household voltage in Italy is (last time I checked) 247 (at 50 Hz)... I rented an apartment where the lights were perpetually on the yellow side, and the coffee maker took forever - 107 at the outlets.

If I shout at clouds, does a tree falling in the ocean make a sound if it's only bears watching...

 

[wyliesdiesels]

No this outlet connects to the main panel.
How could 250v in a 250v outlet be on the high end, especially when each hot wire coming in has 125 (ish) volts? If its a 250v outlet isn't 250 volts normal?

Also, it is a 3 prong outlet. The metal box itself should be grounded to the ground bar inside the panel correct?

While the outlet is rated for 250v, 250v measurement is on the high side because nominal voltage is 120/240. The outlet rating has nothing to do eith nominal voltage supplied to building. Transformers are rated for 120/240

I have 250v outlets in my house for the range and dryer but the measured voltage is 240v.... PoCo has a 5% voltage range so 228-252. If i was getting 250v i would give them a call cause it means the autotransformer at the substation is not working correctly.

 

[Bert_]

250v with no load isn't bad. It will drop a bit under load. If I get less than 240 unloaded I usually ask them to tap it higher.

 

[Toomanytools?]

I thinking most of the posts here are on the 110,120 or 220,240 volts debate and history. That's all good but looking at the OP question, 1) Will the outlet in my garage work with this power supply or will I have to swap out outlets in my garage to a specific one for 220V?
I get the feeling he/she thinks that if the panel has 240v at the breaker you can change the "outlet" to get a different output. I could be wrong. Maybe that should be addressed.

 

[American Locomotive]

These were never "standard", and nobody alive today ever saw them so it's not like they were talking about when they were a kid.

120VAC wasn't standardized until 1967. There are currently 100+ million people alive who were born before 120VAC was the standard.

If Edison was the only power company arround, and he settled on 110v, and everyone else settled on 110v - then it is a defacto standard, even if it isn't codified.

Again, input and output are two different things with two different tolerances that hopefully overlap somewhere. If your outlets ever put out 440, something is wrong.

440v 3 phase was the norm back in the first have of the 20th century. I've even seen ancient transformers rated for 440v.

Those are also great examples of incorrect word usage. They are however more common, and refer to things people actually used in their recent memory, and actually were standards.

I lived ina time when you could only watch movies on film and you could only buy the newest music on vinyl. I still never lived in a time that 110 or 220 was standard.

Things certainly varied a lot more in the old days, but not the "standard".

110 and 220 didn't come out of thin air. That's what the voltages used to be, so it stuck with people. Thats what my father always called it, because that's what his father - a licensed master electrician called it. He called it that, because that's what it was.

 

[Darkness]

what it was.

What it was, not what it is. A weird old standard from when people didn't even remotely understand electricity. And working there doesn't mean much...my dad was a truck driver, he thinks it makes him a diesel mechanic. Truth is he doesn't know how to open the hood...

110 and 220 are simply incorrect terminology. As to the question that was originally asked, they are the same thing as 120/240.

I guess you can call your dog a horse if you want to. Doesn't make it any less incorrect. Language is important. Regular gasoline used to be well over 90 octane, not too many decades ago. Does anybody still refer to it as that? No, because somebody would instantly tell them they are wrong. There are a WHOLE LOT of things people said 50 years ago that would be considered nothing but incorrect today.

My grandpa referred to anybody that wasn't white as "colored", and people of African descent had their own special word. Is it OK for me to keep talking that way because grandpa was a racist and racism was OK in the 50s? Things change.

Somebody always has to argue about pointless things online, right? The bottom line is, there is no 220 outlet in North America. Period. If you measure a North American outlet and 220 volts comes out, something is broken.