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220v vs 240v outlet questions {filename} | ElectriciansForums.net
220 vs 240 outlet questions
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 butt 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
 
I think the point here is that supply voltages are nominal. There are two popular ranges, one just over 100V that has been 110, 115, 117, 120V over a century of evolution, and one about twice that, 220, 230, 240, 250V. In the UK it has been 240V for a long time, in mainland Europe 220V. Now we all call it 230V but we didn't change anything, only the tolerance and the official definitiion. Most equipment will accommodate the whole range, only a few items are rather critical e.g. traditional filament light bulbs, where the life and brightness depend on the voltage being exactly right. So 220V bulbs and 240V bulbs were actually different, but hairdryers not so much.

Your lift specifying 220V 60Hz suggests the motor was made to a non-USA spec, e.g. Brazil uses 220V 60Hz. Your power is also on the high side at 125/250V, so it looks like a significant difference. In reality it will probably work 100% fine, although if the motor were running 24/7 its life might be shortened through higher temperature. The outlet has no influence on anything - its voltage specification is to ensure that appliances of completely different voltages are not plugged into the wrong circuits, and to inidcate the maximum voltage that the outlet itself can withstand. To reduce your 250V to 220V would require a step-down transformer. In industry where machinery is operated to very tight tolerances, that is what would be done.

A USA-based electrician will need to advise re. the grounding. You mention a 30A 3-prong outlet with a neutral prong. This suggests to me a NEMA 10-30 which was used in the past with a combined neutral/ground connection. I believe this has been deprecated under the NEC since 1996, but because your lift does not require a neutral, using the 3rd prong for its safety ground might still be acceptable, and this might dictate how the green ground wire is connected in the box.
 

220v vs 240v outlet questions {filename} | ElectriciansForums.net
220 vs 240 outlet questions
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 butt 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
As @lucien said if you measured our voltage with a meter you would read 240ac. For years people have called our voltage 220/110 for reasons I don’t know why. Make no mistake you have 250vac it sounds like that’s what the power company is giving you. All power company’s give 240vac up to 250vac. That ground should always be hooked up
 
As @lucien said if you measured our voltage with a meter you would read 240ac. For years people have called our voltage 220/110 for reasons I don’t know why. Make no mistake you have 250vac it sounds like that’s what the power company is giving you. All power company’s give 240vac up to 250vac. That ground should always be hooked up
As far as the ground..would it be best to ground the metal outlet box: 1) By having a
wire going from ground bar in main panel box to ground screw screwed to the inside the box and leave it at that.....or 2) have the ground wire coming out of the outlet, grounded to the metal box, and terminate it obviously to the ground bar in the main panel box?? Orr do both for added safety? Thanks
 
As far as the ground..would it be best to ground the metal outlet box: 1) By having a
wire going from ground bar in main panel box to ground screw screwed to the inside the box and leave it at that.....or 2) have the ground wire coming out of the outlet, grounded to the metal box, and terminate it obviously to the ground bar in the main panel box?? Orr do both for added safety? Thanks
All you need to do is ground all metal boxes back to the main panel good luck my friend and you will be fine with your voltage
 
I think the point here is that supply voltages are nominal. There are two popular ranges, one just over 100V that has been 110, 115, 117, 120V over a century of evolution, and one about twice that, 220, 230, 240, 250V. In the UK it has been 240V for a long time, in mainland Europe 220V. Now we all call it 230V but we didn't change anything, only the tolerance and the official definitiion. Most equipment will accommodate the whole range, only a few items are rather critical e.g. traditional filament light bulbs, where the life and brightness depend on the voltage being exactly right. So 220V bulbs and 240V bulbs were actually different, but hairdryers not so much.

Your lift specifying 220V 60Hz suggests the motor was made to a non-USA spec, e.g. Brazil uses 220V 60Hz. Your power is also on the high side at 125/250V, so it looks like a significant difference. In reality it will probably work 100% fine, although if the motor were running 24/7 its life might be shortened through higher temperature. The outlet has no influence on anything - its voltage specification is to ensure that appliances of completely different voltages are not plugged into the wrong circuits, and to inidcate the maximum voltage that the outlet itself can withstand. To reduce your 250V to 220V would require a step-down transformer. In industry where machinery is operated to very tight tolerances, that is what would be done.

A USA-based electrician will need to advise re. the grounding. You mention a 30A 3-prong outlet with a neutral prong. This suggests to me a NEMA 10-30 which was used in the past with a combined neutral/ground connection. I believe this has been deprecated under the NEC since 1996, but because your lift does not require a neutral, using the 3rd prong for its safety ground might still be acceptable, and this might dictate how the green ground wire is connected in the box.
Good Post. The voltage harmonisation to 230 meant in practice no one changed anything in practice, they just tweeked the tolerances to embrace all systems. Ironically, we now have a 230 volt system here. One advantage it has is if consumers too close to the trafo were suffering issues with lamps blowing due to the increased voltage, you order in some lamps, from Europe rated at 220.
 
All you need to do is ground all metal boxes back to the main panel good luck my friend and you will be fine with your voltage

Are you saying that you don't connect a ground to the outlet/receptacle?
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One advantage it has is if consumers too close to the trafo were suffering issues with lamps blowing due to the increased voltage, you order in some lamps, from Europe rated at 220.

That makes no sense, if the vokatge is too high then 220V lamps will suffer worse than the usual 240V ones.
 
Are you saying that you don't connect a ground to the outlet/receptacle?
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That makes no sense, if the vokatge is too high then 220V lamps will suffer worse than the usual 240V ones.
Of course we ground the switches or receptacles I thought that was a no brainer. To make a long story short our voltage in the state I’m in is 240/120vac
 
Of course we ground the switches or receptacles I thought that was a no brainer. To make a long story short our voltage in the state I’m in is 240/120vac

Well the OP appeared to me to be asking if he needed to ground the box, or the box and the reptacle (he said the receptacle has only 3 pins 2 hots and 1 neutral)

Your answer of just ground the box appeared to suggest that the receptacle does not need a ground.
 
If it's a 10-30 dryer outlet then no, it doesn't have a ground contact. Historically it was an example of TN-C with the casing of the appliance was referenced to the neutral. But we don't know for certain what outlet the OP has.
 
Well the OP appeared to me to be asking if he needed to ground the box, or the box and the reptacle (he said the receptacle has only 3 pins 2 hots and 1 neutral)

Your answer of just ground the box appeared to suggest that the receptacle does not need a ground.
Well to be clear, the 3rd wire is not a neutral (if i typed that before im sorry) but a ground, since 240 v doesn't need a neutral.

So I should ground the actual receptacle to the inside metal box? Yes or no?
Also i have a 4th wire in there doing nothing. Would just running that from the ground bar in the panel box to another ground screw inside the outlet box be added ground saftey???? Thanks
 
If it's a 10-30 dryer outlet then no, it doesn't have a ground contact. Historically it was an example of TN-C with the casing of the appliance was referenced to the neutral. But we don't know for certain what outlet the OP has.
Maybe these pics will help..probably not though
 

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They do, and I guessed right, it's a 10-30 outlet which has two hots and a neutral but no ground. You say a 240-volt appliance does not need a neutral, but many appliances that took most of their power at 240V still had some 120V components, e.g. the timer in a 240V dryer, which ran between one hot and neutral. Obviously your lift requires only 240 but presumably does need a ground.

Today I believe an L6-30 or at least a 6-30 would be specced, as this has the two hots and ground but no neutral. I don't know the NEC well enough to say what would need to be done to change it to meet code
 
They do, and I guessed right, it's a 10-30 outlet which has two hots and a neutral but no ground. You say a 240-volt appliance does not need a neutral, but many appliances that took most of their power at 240V still had some 120V components, e.g. the timer in a 240V dryer, which ran between one hot and neutral. Obviously your lift requires only 240 but presumably does need a ground.

Today I believe an L6-30 or at least a 6-30 would be specced, as this has the two hots and ground but no neutral. I don't know the NEC well enough to say what would need to be done to change it to meet code
@Lucien for years we always used the ground actually for the neutral on a 3 wire configuration. As of the 2014 edition of the NEC if you do any work and bring it up to code which means 2 hots 1 neutral and 1 equipment ground which also means changing the cord and receptacle to a 4 wire system
 
Ah OK, I was hoping you would clue me in with that. So in theory, you might find a 10-30 or 10-50 outlet with what is technically a ground, and another with what is technically a neutral? Would it be acceptable for the OP to use the L-shape prong on his 10-30 as the frame ground for his vehicle lift?
 
Ah OK, I was hoping you would clue me in with that. So in theory, you might find a 10-30 or 10-50 outlet with what is technically a ground, and another with what is technically a neutral? Would it be acceptable for the OP to use the L-shape prong on his 10-30 as the frame ground for his vehicle lift?
Yes the L shaped prong is designed for your equipment ground only but years ago it has been used as the neutral
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Yes the L shaped prong is designed for your equipment ground only but years ago it has been used as the neutral
Yes the L shaped prong is designed for your equipment ground only but years ago it has been used as the neutral
Dryers and stoves are the most widely used appliances that still to this day are using the equipment ground or L shaped prong as a neutral but as I stated if you ever have to work on them you have to bring it up to code according to the 2020 edition of the NEC to a 4 wire plug and receptacle
 
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