Running a 220 20 amp breaker

[Scott Brandstetter]

I have learned a lot from my father and very thankful for all he has taught me over the years. One thing that has always stuck with me is don't mess with 220 wiring, hire a professional. I need to run 220 to my shop and have done quite a bit of reading and watching videos and just can't understand how installing it is any different (danger wise) than running any other new breaker.

I have installed countless 110 breakers over the years and never had an issue. Of course I have always respected electricity in general, take all necessary precautions, never in a hurry, double and triple check my work. Is there really any more danger in running 220? I certainly don't want to be penny wise pound foolish but I don't want to pay an electrician a few hundred bucks for something I can do.

Am I missing something? Please be honest and let me know if I'm being stupid by not letting the professional handle this for me. Thanks in advance

[Mike Cutler]

Pull the proper permits, get it inspected, and you should be fine.
The difference is primarily in the changes in the grounding and bonding requirements for sub panels that have come about in the past decade or two.
Adding 120 circuit is generally "safe" because the ground/bond scheme is already in place, 240 has "variables".
Of course this doesn't mean that many 120 circuits are not improperly installed, resulting in code violations.

[Ole Anderson]

It's not rocket science.

[Don Jarvie]

Its really no different than 110. You use a double 20 amp breaker (2 slots) and each hot (black and white) go to each breaker and you attach the ground to the ground bar. Only difference between 110 and 220 is the white goes to a breaker on a 220 where on 110 the white wire would go on the neutral bar. You end up getting 110 on each hot line for 220.

As for the motor you attach either the black or white to each line in since your getting 110 on each line.

[Mike Henderson]

Its really no different than 110. You use a double 20 amp breaker (2 slots) and each hot (black and white) go to each breaker and you attach the ground to the ground bar. Only difference between 110 and 220 is the white goes to a breaker on a 220 where on 110 the white wire would go on the neutral bar. You end up getting 110 on each hot line for 220.

As for the motor you attach either the black or white to each line in since you're getting 110 on each line.

What I like to do is use a large red felt tip pen and color the white wire red on both ends of the run - just so the next person who comes along doesn't think it's a 120V circuit. I also use a fine black felt tip pen and write on the outside of the wire "240V" anywhere the wire shows - such as if you ran it through your attic. Again, this is just to let the next person who comes along know that this is a 240V circuit and not a 120V circuit.

And just let me just add one comment. You are not getting 120V on each line, unless you are referring to the voltage from each wire to ground. The voltage between the two wires is 240V, single phase, which is what the motor will see. The voltage to ground is immaterial unless you grab the bare end of either the black or red wire - in that case, you will only be shocked by 120V, not 240V. If you grab the bare end of both the black and red wires at the same time, you will experience a shock of 240V.

Mike

[I will add that running a 240V circuit is not rocket science, as Ole pointed out.]

[David Falkner]

I did my own subpanel with no problem. On the white wires (which you can see in the subpanel on the right), I wrapped red tape to indicate they are hot. This is what my electrician friend advising me suggested.

Subpanel, power station.jpg

[John Coloccia]

The main difference in terms of safety is falling from a 4th floor window vs. an 8th floor window. Either way, don't fall from the window. Honestly, running a 240 line is slightly easier because two of the three wires terminate at the same place. It's tough to screw up.

[roger wiegand]

In US residential wiring there are no "240V" wires. Each wire of a 240V circuit is at 120 V relative to neutral, one +120 and one -120. The safety concerns are identical. It's not just a good idea to mark white wires used in a three wire 240V circuit (e.g. without neutral), it's required. Wrapping the end of the wire with black or red electrical tape is common.

[Jim Seyfried]

I'm not sure about any more dangerous...it's the amps (less than 1) and path it takes that will harm/kill you. The best practice is to have the power off when ever possible. For residential I would think that would be just about always. I've been shocked worse by 120v than by 240v. What are you wiring up? Does it just use 240v or does it need to have 120v too? You might need 3 wires + ground.

[Rollie Meyers]

I'm not sure about any more dangerous...it's the amps (less than 1) and path it takes that will harm/kill you. The best practice is to have the power off when ever possible. For residential I would think that would be just about always. I've been shocked worse by 120v than by 240v. What are you wiring up? Does it just use 240v or does it need to have 120v too? You might need 3 wires + ground.

Unless your grabbing both lines you are not getting shocked by 240V.

[Jim Seyfried]

Unless your grabbing both lines you are not getting shocked by 240V.

If you work in a factory for 35 years with 3 phase, 4 wire delta distribution it can happen. However, my point was it is the amps and path more than the voltage that will harm you and to work safe, turn the power off when ever possible.

[Dennis Aspö]

You (people in the thread in general) seem to use 110 and 120 and 220 and 240? Which is it, or do you have both in the states?

[John Coloccia]

You (people in the thread in general) seem to use 110 and 120 and 220 and 240? Which is it, or do you have both in the states?

It's 120V per leg, and when you use two legs together (out of phase) you get 240V. That's RMS, not peak of course, because it's an AC measurement, and that's the most logical way to measure it so that you can figure out power. For whatever reason, and I'm not sure it's a good reason to be honest, in the US we've decided that the "normal" lines use one leg, with a return at ground potential, for 120V, and we reserve 240V for ovens, water pumps, air conditioners, power tools, etc. Seems kind of crazy to me, to be honest.

110V is a historical value. If memory serves, that may even go back to Edison's DC power distribution system.

[Rollie Meyers]

You (people in the thread in general) seem to use 110 and 120 and 220 and 240? Which is it, or do you have both in the states?

110,220, are obsolete & to put it bluntly, a ignorant description of US voltages.

[Jim O'Dell]

110,220, are obsolete & to put it bluntly, a ignorant description of US voltages.

Some things are just hard to change in our minds. I wired my whole shop, then had a fellow Creeker who just happens to be a licensed Master Electrician come look it over. He caught one mistake on the ground/neutral bonding screw, but that was all. Up and running for over 8 years now and nothing has burned down!
As others have said, working on 240 is no different than working on 120. Either way you should have the power turned off for safety. Learn how to use a decent volt/ohm meter and check the wiring before firing things back up, and you will be good.
Now, with that said, if this is to your house and you do something to burn the house down, your Insurance Co. may have some issues with with payment for the loss! And I've heard some places won't allow you to work on anything electrical unless you are licensed. Jim.