How to wire 120v and 220v outlets

Well Dan, first find a multimeter somewhere and confirm that the potential between the two 115-v "hot" wires is indeed 220 v. Then to be absolutely sure not to kill yourself, confirm that the "cold" wire goes to cabinet frame, to the mid or "ground" connection of your 110-v outlets

Note: When a load is applied you might detect a small voltage between the two "grounds"

Depending on the load presented by your compressor etc and whether you have other protection upstream, your safest bet is to connect the new outlet at the output side of your two breakers

Is there a reason you don't just hire that same electrician again?

Thanks for the advices guys! We dont hire him again because that there's a 3 and a half months delay to get an electrician here... Too many projects and not enough people to do the job. I could ask an electrical engineer (a friend of mine) to inspect the job to be sure, but he's more in the industrial side of the job and he's very occupied too so he could not do the job for me or with me. If I understand well what you said, I only need to connect a new circuit for the 220 outlet in parralel from the 2 existing breakers in the sub-panel to an outlet? If I did that, wouldn't that give me a 35amps outlet? if so, I would exceed the maximum rating of my breaker inside the house or would it be a 15 amps outlet because that the outlet would only supply the maximum rating of the lowest breaker? There are still many empty spots in my sub-panel so could I just (in accordance with the code) add a 220v 30a breaker and wire my 220v outlet from there and keep my two other breakers/outlets for the 120v as they are?

Btw: Sorry for my bad english, I'm a french canadian

Each of the 110-v outlets has three terminals. If like ours they are neutral or cold (sl larger) usu left, hot then to the right, and ground on the bottom. The two hots connect to the respective 220-v receptacle hots; it shouldn't matter which goes to which. Ground to ground

However as I mentioned check first to confirm you have 2-phase 220 v. A digital voltmeter is very cheap these days

Yes

Yeah, I do have 220v between the two "hot" wires (mesured between my 2 breakers). So what should I do now? Thank you very much for your help, its appreciated!

Dan I thought I had explained what to do in my posting #…….662 above. I don't know what else to say

Yeah, but I wasn't sure if I needed to connect my two circuits (two 120v and one 220v) on the same breakers or if it was better to install a new double 220v breaker and connect all my circuits to it so that I could get all the 30 amps? Sorry for the confusion man...

In order to get the whole 30 A available, you need to wire the two hot wires (220 V) through a single 30 A circuit breaker.

Otherwise, you'll get the power available from the less powerful breaker, i.e 15 A..

I'm not that good in english so its hard for me to clearly explain my question, but I want to know if I could add a 30 amps breaker and my two existing 120v (15 amps and 20 amps) breakers because that would put my total amperage of the sub-panel higher than the rating of the breaker in the house going to the sub-panel.

Dan, you are indeed a bit confused about the current you can draw from your outlets.

Adding the power of two circuit-breakers of 20 and 15 A in parallel do NOT increase the available power. Instead you only get the power of the less powerful one, meaning 15 A.

But if you wire another 30 A circuit-breaker with the two hot wires (220) in your sub-panel, you'll get 30 A through it, provide your house panel circuit breaker is at least a 30A rating..

By all means install the new breaker

Not at all Dan, the confusion was mine

I understand the thing with the 15 amps breaker for the 220v, but what I want to know is can I plug my two 120v circuits and my 220v circuit on the same breakers (one 20a 120v breaker and 15a 120vbreaker and 220v 15a circuit plugged to these two breakers)? Would this be ok or should I add a new 220v 30a breaker to put only my 220v circuit on it Nd lesve my 15a 120v and my 20a 120v circuits and breakers in place and still use them?

Thanks guys! I'll install a 220v 30a breaker nd connect my 3 circuits to it (two 120v and one 220v). Your help was very appreciated!

If I understand your question, my answer is this:

- Leave the 120 V circuit-breakers as they are so you can continue to use them.

- Install a new 30 A circuit-breaker, wired in 220 V, so can use your welding machine. In order to do this, use the two hot wires you have in the sub-panel, arriving from the house.

There could be a sort of language barrier here. Dan, maybe it would help if we explain the diff between current and voltage: Voltage is compared with pressure, like pounds-per-square-inch and current with flow, like gallons-per-minute

http://www.google.ca/#hl=en&gs_rn=7&gs_ri=psy-ab&pq=voltage%20is%20potential%2C%20current%20is&cp=13&gs_id=5s&xhr=t&q=current+and+voltage&es_nrs=true&pf=p&sclient=psy-ab&oq=current+and+v&gs_l=&pbx=1&bav=on.2,or.r_qf.&fp=3bbcd90b84c3d114&biw=1217&bih=726

More than ever, I'm thinking a professional electrician would be a good investment. I am just not convinced that communication here has been perfect.

I agree that the communication was not perfect here but I firmly believe that the advice given was quite pertinent.

Having trained quite a number of electrical engineers and still doing, I also believe that this wiring can be done by a gifted handyman..

Let's hope that Danlebarbare will not do that in a barbaric way..

Haha guys I'll be VERY carefull doing this job and an electeical engineer will verify the job. I know the difference between volts and amps, but I usually deal with DC current (making electronic circuits). I also already installed new outlets and lights in the house, so I have a little electical experience with AC, but not much....