I used to make my living as an electrician. I did pretty good at it, and even owned my own business for a while. As I started approaching 40 my knees didn't agree with crawl spaces and attics, so back in 1999 I started college to be a teacher.

 

So for the last 18-19 years electricity has been more or less a hobby and helping friends and family.

 

Now to my question/dilemma; my neighbor is building a workshop. He's putting a heat and air unit in it that is 220 volts 20 amps, and no neutral. Just two hots and a ground. I can't wrap my mind around how it's going to work without the neutral return, and how it's supposed to be wired.

 

I can't find anything on the internet about it. Could someone please enlighten me?

 

Thank you

rs

I've asked about this when I've seen it on jobsites before. I had an electrician tell me that this works because of alternating current. The two hots are 180° out of phase with each other.

I've asked about this when I've seen it on jobsites before. I had an electrician tell me that this works because of alternating current. The two hots are 180° out of phase with each other.

 

When the inspectors come out, they are cool with it?

So. I'm pretty sure he'd need a neutral because what happens when you have something on a circuit with an unbalanced load? The neutral helps with that. You can't rely solely on the ground because that's more for ground faults.

I'm not positive, but i don't think an inspector would pass that

When the inspectors come out, they are cool with it?

 

Its specific to 220 and 240 volt electric. I've only seen it on refrigeration units in new construction applications, and I've not ever had an inspector bat an eye at it.

I've asked about this when I've seen it on jobsites before. I had an electrician tell me that this works because of alternating current. The two hots are 180° out of phase with each other.

 

I don't think this is true. When you bring a 240/220 volt service into a house take a look at the transformer. The high wire (for a normal residence/ business) will be one single wire coming into that transformer. That transformer has a center tap in which it is able to convert voltage for distribution voltage into two 120 volt hots and a ground. So therefore they technically are the same phase, they can't be 180° out of phase. There are 3 phases that come out of the power plants, each phase is 120° out of phase with the other.

 

And for backgrounds sake, someone way smarter than me can put me in my place. I only have an associate's degree in power systems. So i have most of the basics

Edited July 30, 20188 yr by Kentucky Windage

So, I'm going to walk back from what I previously posted. At the distribution transformer it does takea single phases and splits it into two "phases" that are 180° out of phase with the other.

So, I'm going to walk back from what I previously posted. At the distribution transformer it does takea single phases and splits it into two "phases" that are 180° out of phase with the other.

 

Sincerely, you probably know more than I do. I was just going 100% on what I've been told by electricians on my jobsite.

Yesterday we went to another neighbor's garage and looked at his wiring. He has a welder and air compressor that both do not have a neutral. He has 10/2 running from the panel to the unit. They work fine. I still don't understand how.

I suppose as long as there are no unbalanced motor loads everything should be fine. I'd make sure your grounding is good.

Here is what I found on installing a 220 volt outlet. You would not use a neutral.

 

Installing a new 220 outlet isn’t much different from a 120-volt outlet. However, you can only put one 220 outlet per breaker/circuit. And you will install two hot leads to the outlet and not use a neutral for this type of outlet in the video.

In the below diagram you will notice that for a 220-volt outlet you would need a two pole breaker. What this means is that the breaker will take the power from the panel by the two very different phases. Each one is 110 volts. Combined you have your 220 volts. However, you will still need a ground as you can see. Some need a neutral as well. Most of the time these would be things like your stove. But for now, this pretty much covers a simple 15 or 20 amp 220 volts.

The wiring needed for this type of insulation you would use 12/2 wire for a 20 amp installation.

 

22

I can replace a plug, replace a switch, put up a fan or a light, but dont ask me to wire a darn thing. I understand tax code better than this stuff, lol.

 

 

To be fair, I did have to call @Godot once to help we wire up something, lol.

I used to make my living as an electrician. I did pretty good at it, and even owned my own business for a while. As I started approaching 40 my knees didn't agree with crawl spaces and attics, so back in 1999 I started college to be a teacher.

 

So for the last 18-19 years electricity has been more or less a hobby and helping friends and family.

 

Now to my question/dilemma; my neighbor is building a workshop. He's putting a heat and air unit in it that is 220 volts 20 amps, and no neutral. Just two hots and a ground. I can't wrap my mind around how it's going to work without the neutral return, and how it's supposed to be wired.

 

I can't find anything on the internet about it. Could someone please enlighten me?

 

Thank you

rs

 

 

It's because the two, 180 degrees out of phase, feed wires essentially take turns being the return wire every time the phase switches.

 

240V is the difference between them, and so when leg 1 is at +120V the other leg is at -120V and power is flowing from leg 1 to leg 2, but half a cycle later they are swapped and the power is flowing in the opposite direction, with leg1 acting as the return.

 

 

AC current requires a return path, electricity goes out one way and back the other. With 120V wiring in the US, you have a center tapped transformer with two hots that total 240V. The neutral is that center tap, which combined with only one of the hots gives you 120V. Use both of the hots and you have 240V. The only need for the neutral is to get a 120V circuit.

 

It's smart to wire a 240V circuit with a neutral conductor even if you don't need it for the current appliance since it's easier to run the extra wire once in case you need it in the future, but that's not required.

 

This may help you.

 

 

How to wire 240 volt outlets and plugs

Edited July 30, 20188 yr by coldweatherfan