Some powerful appliances require extra juice, so they need 220 volt lines and outlets, which draw electricity from 220 volt electric panels. In some quarters, the term "220 volt" has become synonymous with "240 volt," which in most countries has become the dominant standard, just as 120 volt circuits have replaced 110 volt models.
If your home electricity was put in before 1980, you may have actual 110/220 volt circuits, which may need to be upgraded to support machinery requiring 240 volts (some kinds of equipment will work fine without the upgrade, others may experience performance challenges).
Installing or adjusting electrical components like these is a job for a professional, and in some places it's illegal to attempt without certification. If you're interested in learning about the process, though, you might enjoy checking out how it gets done. Just remember, this kind of project can be dangerous if you don't know what you're doing.
Step 1 - Choose the Location
If the appliance will be placed in front of and hiding the outlet, as is often the case for a clothes dryer, the electrical box can be screwed on the surface of the wall close to the floor, where it will mostly hide the hole. From this hole, the wire will snake down to the electrical panel and hook up to the breaker, usually in the basement. For this type of installation, complete the safety evaluation in Step 2 and then head straight to Step 7.
For an in-wall installation, the outlet’s location should be chosen carefully to avoid any existing electric wires or plumbing. The nearest stud should be located and marked on the wall at the required height.
Step 2 - Secure Worksite Safety
All the circuit breakers feeding the vicinity should be turned off to prevent the risks of electrocution or fire from a short circuit. If there's any chance of damaging plumbing, the water supply should be turned off as well.
The immediate area of the wall should be scanned with a digital multi-scanner as a secondary precaution to detect metal plumbing and electric wires and help prevent accidental damage.
Always proceed with caution while working inside walls, probing and feeling for any resistance or obstructions from undiscovered items.
Step 3 - Cut the Opening for the Electrical Box
Drill a hole where the box will be placed. If you don't know quite where the stud is, you can drill a series of small holes moving toward the stud location until the bit hits it. The electrical box can then be placed flat on the wall at the stud mark and outlined with a pencil. The outline of the box can now be cut out with a keyhole saw or similar tool.
Step 4 - Drill a Path for the Cable
With the box opening cut out, the wall can be checked for obstructions. A hole slightly larger than the size of the cable will need to be drilled from the basement up through the wall plate directly under the outlet’s opening.
To locate the position where it should be drilled from the basement, drill a small hole through the floor with a 6” (150mm) or longer drill bit, in the corner of the baseboard and the floor.
Inserting a long piece of wire through the hole and leaving it hanging into the basement will give up its location from below. From that spot in the basement, measuring 2” (50mm) over and perpendicular to the orientation of the wall will determine where to drill with a spade bit.
With that done, if there was an obstruction in the wall above, extension stems are available for deeper reach so the drilling can be completed.
Step 5 - Put the Cable Through
Since there could be multiple holes to pass through, this may require some imagination, but any way it’s done requires the use of a long, skinny and stiff dowel, rod, wire, or something else of the sort.
One approach is to tape the dowel to the cable’s end and push it through from the basement, aiming for holes already made.
Another method is to insert the dowel alone through the hole(s) from the basement. When it reaches the outlet’s opening, a piece of rope, or twine, or soft wire can be attached to it, allowing you to pulling everything back down to the basement, while keeping the other end outside the wall. The makeshift fishing gear can be taped up to the cable and pulled through the outlet’s opening.
Step 6 - Install the Electrical Box
With the cable pulled out through the outlet’s opening, about 8” (20cm) of its jacket must be removed using a utility knife. With the three wires and the ground wire exposed, 3/4” (19mm) of insulation must now be removed from all three insulated wires.
A cable connector is then secured through a knockout plug opening and the cable passed through it and secured, inside the box. The box is then pushed into the opening, cable end first, and fastened in place onto the stud.
Step 7 - Wire In the Outlet
Looking at it from the back (Fig 2b), all of the outlet’s terminals look the same. Every terminal screw is loosened and the red and the black wires are inserted and secured at the two elongated slots’ terminals.
The bare copper (ground) wire is fastened to the semi-circle-shaped opening’s terminal and the white Neutral wire to the “L” opening opposite to the ground. The outlet cover can then be screwed in place onto the box.
For a range receptacle (Fig. 3a & 3b), the hot and neutral lines are all attached to identical slots so that the one opposite the ground semi-circular opening is for the neutral and the other two opposites ones are for the two hot wires.
It does not matter, however, which of the red and black wires goes on which of the hot terminals.
Step 8 - Wire to the Electric Panel
The cable can then be attached at intervals to the basement’s ceiling joists right up to the electric panel. Before removing the front of the electric panel, a battery-operated trouble light should be put in place to illuminate the work area. The main circuit breaker feeding the panel (Figure 5) must be turned off so the power is cut off to the whole house.
With the front panel removed (Fig. 6), a 220 volts properly rated breaker can be inserted into an available double slot and switched OFF.
A cable connector should be secured to the electric panel through a knockout plug opening. The cable is then routed down to the cable connector and its jacket marked where it will go in through the cable connector.
The distance between the cable connector and the ground bus bar, plus an extra couple inches, is added to the mark on the cable to where the cable is to be cut, and with that done, the cable’s jacket is cut around its circumference at the mark and removed.
All the wires are then passed through and the cable is secured with the connector clamp, the bare ground wire connected to the ground bus bar, the white wire to the neutral bus bar, and each of the two hot wires to one of the breaker’s terminal in no specific order.
The appropriate rectangular breaker knockouts can then be removed from the cover, which can afterward be put back and secured in position.
Step 9 - Back in Operation
To prevent a surge of power through the house, it's a good idea, before switching on the main power breaker, to switch all the breakers off inside the electric panel. Starting with the main breaker, turn every breaker back on one at a time, leaving the newly added breaker for last. The 220 volt appliance can now be plugged in and tried out!