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How to wire 120v and 220v outlets

 
 
Reply Sat 23 Mar, 2013 12:50 pm
Hi, I would like to know how to wire a 220 volts outlet and two 120 volts outlets on the same 30amps sub-panel installed in my shed. In the sub-panel, there's only a 120v 15amps and a 120v 20 amps breaker installed by an electrician. Its wired to a 220v 30 amps breaker in the house. The 220v outlet would be used for welding or an air compressor and the 120v outlets would be used for light and smaller power tools.
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Type: Question • Score: 4 • Views: 5,825 • Replies: 18
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dalehileman
 
  1  
Reply Sat 23 Mar, 2013 12:58 pm
@Danlebarbare,
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
0 Replies
 
Ragman
 
  2  
Reply Sat 23 Mar, 2013 01:11 pm
@Danlebarbare,
Is there a reason you don't just hire that same electrician again?
Danlebarbare
 
  1  
Reply Sat 23 Mar, 2013 01:40 pm
@Ragman,
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
dalehileman
 
  0  
Reply Sat 23 Mar, 2013 05:12 pm
@Danlebarbare,
Quote:
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?
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

Quote:
would only supply the maximum rating of the lowest breaker?
Yes
Danlebarbare
 
  1  
Reply Sat 23 Mar, 2013 09:09 pm
@dalehileman,
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!
dalehileman
 
  1  
Reply Sun 24 Mar, 2013 08:36 am
@Danlebarbare,
Dan I thought I had explained what to do in my posting #…….662 above. I don't know what else to say
Danlebarbare
 
  1  
Reply Sun 24 Mar, 2013 08:50 am
@dalehileman,
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...
timur
 
  1  
Reply Sun 24 Mar, 2013 08:56 am
@Danlebarbare,
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..
Danlebarbare
 
  1  
Reply Sun 24 Mar, 2013 09:09 am
@timur,
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.
timur
 
  1  
Reply Sun 24 Mar, 2013 09:31 am
@Danlebarbare,
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..
dalehileman
 
  1  
Reply Sun 24 Mar, 2013 09:35 am
@Danlebarbare,
Quote:
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?
By all means install the new breaker

Quote:
Sorry for the confusion man...
Not at all Dan, the confusion was mine
0 Replies
 
Danlebarbare
 
  1  
Reply Sun 24 Mar, 2013 09:39 am
@timur,
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?
Danlebarbare
 
  1  
Reply Sun 24 Mar, 2013 09:41 am
@Danlebarbare,
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!
timur
 
  2  
Reply Sun 24 Mar, 2013 09:45 am
@Danlebarbare,
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.
dalehileman
 
  0  
Reply Sun 24 Mar, 2013 10:58 am
@timur,
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
0 Replies
 
roger
 
  1  
Reply Sun 24 Mar, 2013 12:03 pm
@Danlebarbare,
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.
timur
 
  2  
Reply Sun 24 Mar, 2013 12:25 pm
@roger,
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..
Danlebarbare
 
  1  
Reply Sun 24 Mar, 2013 03:05 pm
@timur,
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....
0 Replies
 
 

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