i've posted this elsewhere but it seems to always come up. putting in 220v: When working with electricity always: Turn off the power. Test the wires to ensure the power is off. Lock out the panel box, so no one can accidentally turn the power back on while you are working. you really should, but probably won't: Check with local authorities to see if a permit is required. (it usually is) Have your work checked by an inspector. To avoid overloading the circuit, consult a licensed electrician. <!--Signature-->
Wire Gauge Maximum Amperage 14-------------- 15 12 --------------20 10 --------------30 8--------------- 40 6 ---------------50
Two-Wire or Three-Wire Cable? Whether you need two- or three-wire cable depends on the equipment and plug that will be needed by the new circuit. MOST welders only require two hot wires and a ground. In this case you can use two-wire cable, just be sure to color code the white wire as a hot wire. Others require two hot wires, a ground wire and a neutral wire. In this case you need to use three-wire cable. i'm putting in a three because who knows what i'll need in the future
About Two-Pole Breakers If you are simply moving an existing 220 volt receptacle, you can use the breaker that's already in your service panel. If you are adding a new 220 volt circuit, you will need two adjacent open holes in the service panel to accommodate the new circuit breaker. if your breaker box is full you can make a junction box and split your dryer line one for the garage and one runs to the laundry.
Install and Wire the New Receptacle Use the fish tape to pull the cable from the receptacle box to just outside the entry hole for your service panel. Be sure to leave 12" of extra cable protruding from the receptacle box, you will need the extra cable to wire the receptacle Strip 6" of sheathing from the cable extending from the receptacle box. Ground the bare copper wire to the receptacle's ground. Connect the white wire to the receptacle's neutral lug. If you are using a 220 volt plug that only has connections for two hot wires and a ground, there is no neutral, so you can skip this step. Connect the black and red (or white wire coded red) wires to the receptacle's hot lugs. If you are using two wire cable there won't be a neutral wire. Code the white wire red and connect it as you would the red wire in step 4 above. Secure the receptacle in the box and install the cover plate..
Connect the Circuit to the Service Panel Turn off the power at the main breaker and remove the service panel's cover plate. Be careful not to touch the inside of the service panel. Test the panel to be sure the power is off. Connect one tester probe to the service panel's neutral bar. Connect the other probe to each breaker's set screw to test for power. If the tester doesn't show any power, it's safe to work in the box. Connect the white wire to the neutral bar. If you are using a 220 volt plug that only has connections for two hot wires and a ground, there is no neutral, so you can skip this step. Connect the bare copper wire to the ground bar. Connect the black wire to one leg of the two-pole breaker. Connect the red wire to the other leg of the two-pole breaker. If you are using two-wire cable, connect the white wire, coded red, to the other leg of the two pole breaker. Reinstall the service panel cover, restore power to the service panel and test your new outlet. Sweet you now have 220v! <!--Signature-->
Great job Seth, I like the pictures. I'm just about to wire my new garage and I was thinking of adding a sub-panel out there. What would be the best way to do this. I currently have a 200 amp service in the house. I have 3 220v breakers that I'm not using anymore, they were for electric baseboard heaters that I removed. What amp sub should I run and what size wire would I need for this? Thanks- Scott
It's a great tech post, very detailed, but if someone on here hasn't worked with electricty before. I would suggest they hire an electrical contractor or someone who has. 220V is not for the home hobby do-it-yourselfer kinda guy to get into. You don't want an amateur plugging in his new Miller $3000 TIG to some plug he just wired himself for the first time only to short it all out. I've wired up 440V 3 PH myself, but with years of experience behind me.
Seth, do you need to increase wire diameter if you're running it 40'?my garage is separate from the house.
if you wan the details mathematecially here is the facts: http://www.radiolocman.com/shem/shem-cache.html?di=18899 basically : For a long run, though, you should use the next larger size wire, to avoid voltage drops. the ratings i gave are nominal and for under 100 feet.
"Notice there are different size of breakers in the panel. Some of the two-pole breakers are large and take up two full slots, others are narrow and take up only one full slot. Also some of the single pole breakers are wide and take up one full slot, others are narrow and take a half slot. One trick on a full panel like this, is to take out two of the large full slot single breakers, replace them with two half slot single breakers, this frees up a slot for a narrow double ganged breaker for your new 220 service." -thanks squirrel
Thanks, I'll be needing that. Just curious, anyone out there know how you determine what size service you will need for your welder (I didn't see it in the catalog)? Right about the service lugs, I learned that one the scary way years ago.
Be careful with this. Typically twin breakers (that take up only one slot) are configured so that both halves are fed off of the same phase which will not give you 220V and your equipment won't like it. You need to make sure that one side is on phase A and the other is on phase B. Twin breakers are a band-aid for panelboards that are too small - avoid them if you can and I'm not aware of any that can be utlized for 220V loads. In your scenario above you would need to remove 4 full size single pole breakers, install 2 twin breakers which leaves you two full size slots for a two-pole breaker.
i think what squirrel meant is use a pair of the twin breakers to open up a pair of full size breaker spots for the 220 pair. atleast thats how i understood it, thanks for clarifying though. really the best bet for an overloaded panel is to pull a few breakers out, wire up a sub panel and rewire the pulled circuts to the sub panel. then create your new 220 circut from here, total cost at home depot for the parts is under $60. you need a permit for this is CA other states probably too. if you plan to die in yur house you might get away with it or it might cause you to die in your house if oyu do it wrong and doen;t get it inspected. mind you i'm not a liscenced electricianand this is only put up here for refrence. i feel comfortable around electricity, but i did i study electrical engineering in college. only do this if you feel comfortable. if nothing else run the wires and have an electricianhook it up.
You probably need to do some research on your panel first to make sure it will work, but take a look at the panel in the picture above, you'll see a few double gang small breakers that are obviously feeding 220 circuits. If it's an older house, and only has the wide breakers in the panel, don't try it.
Wait a second here... are we talking 3 phase or single phase? If I'm reading 230 vac across the two hot leads on a single phase system, and 115 from each to ground, then what is this phase A and phase B criteria? Just curious here...
Even though it is single phase, each hot lead is typically referred to as a phase with a corresponding 'A' bus and 'B' bus in the panel. Every other breaker position is connected to each phase. A -1 2 - A B - 3 4 - B A - 5 6 - A etc. If a twin breaker is inserted into slot 4 for example, the load would be connected to phase 'B'. To get 220V (220V - 240V whatever you want to call it) you need to connect to both phases in the panel (both hot leads) so the breaker needs to span between adjacent slots. I personally haven't seen a 2-pole breaker that is single pole height that would somehow hit both phases which is how I thought the post I referenced read. I probably read it wrong but I wanted to make sure it was clear to anyone else that you need to connect to both bus bars (not just any two trip handles) to get 220V. Admittedly I don't deal with residential stuff much so such a breaker like that could defintely exist - I'm just not familiar with it.
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