node 2 of fhayashi's home improvement node orgy
Ever move into a new house or apartment, pop out your computer from the boxes, and find that your surge protector cannot be plugged in to the wall because the wall receptacle is the older two-pronged variety? Do not take the cheap/easy/dangerous way out of using a three-prong to two-prong adaptor! Though you can make these safe by properly grounding the adaptor, the real man's man way of fixing this is to change the receptacle. It's relatively quick, easy, and affordable. But beware, you are dealing with electricity, which can be dangerous. Take plenty of precautions. This is not something you can do half-assed. The instructions are for home wiring in the United States of America. I am not a licensed electrician, and neither are you (probably), so beware.
stuff to buy at your local Home Depot or Ace Hardware or whatever (unless you already have)
- screwdriver - you'll need at least a flathead, as older receptacles have flathead-only screws. A Phillips screwdriver makes it easy to install the new receptacle
- new receptacle - these are quite cheap, as low as 34-cents, if you buy a ten-pack. If you're in a water-using place like the kitchen or bathroom, you might explore using a GFCI receptacle to protect from shock hazards. There are also child-resistant models. Pick a color scheme for your whole house - beige or pure white. I like pure white. Also, sockets now come in the traditional two-oval design as well as the new single-big-rectangle design. You get to pick.
- new cover plate - you'll want to pick up a matching cover for your receptacle - both color and socket layout (twin oval or big rectangle). Cover plates also come in a few sizes - the bigger ones are nice to cover the gouged parts of the wall near the receptacle box.
- you may need a wirestripper, but 9 times out of 10, you won't.
- you really want a circuit tester. I have a convenient, cheap one which looks like the end of an electrical plug, with 3 LEDs on it. It tells you if the socket is wired properly, testing for polarity as well as grounding, beyond the obvious fact whether there is electricity running to the socket. An adaptor that let's you plug three-prong sockets into two-prong receptacles is convenient, so you can use this tester on older receptacles.
- Pick a receptacle to work on
- Plug in your circuit tester, with the adaptor - lights should light up, telling you that the receptacle is powered, but not grounded. If you like, you can use a wire lead to attach the grounding tab on the adaptor to the screw holding the receptacle cover on. This should result in the tester showing proper grounding. This means that, although the receptacle is a two-pronger, the receptacle box is properly grounded, as it should be. If this is not the case, I would suggest stopping right now, and think about calling professional help. This HOWTO is how to put a three-prong receptacle into a properly grounded receptacle box.
- Go to your circuit panel/fuse box. Start flipping circuit breakers or pulling fuses until your tester goes off, demonstrating that you have cut power to that receptacle. If you live with other people, you might want to put a note, warning people NOT TO TURN THE BREAKER BACK ON, OR YOU MIGHT GET SHOCKED. (follow the link to circuit breaker, where I'll put up more important safety information soon)
- Now, take apart the receptacle. Using flat-head screwdriver, remove the cover. This is done in most cases by turning the screw in the center of the two plug sockets counter-clockwise until the cover comes off. Then, unscrew the receptacle from the box, by unscrewing the screws above and below the receptacle.
- Carefully pull out the receptacle from the box. There should be plenty of wire length to allow you to pull the receptacle completely out of the box. Note one white wire and one black wire. If at this point you see bare wires, you want to call a professional - your wiring is really, really old and you should have it changed completely. Bare wires means your wiring is older than your grandmother, and may lead to fires in your house.
- Unscrew the white and black wires from the old receptacle. Throw the receptacle away.
- Get your new three-prong receptacle out. Notice the wire attachment points. There are two brass screws on one side, two silver screws on the other side, and a green screw somewhere else. Fancy receptacles have spots you can simply plug in bare wire to be held automatically, but this is usually for professionals who have to install hundreds at a time. I just use the normal screws.
- additional facts on receptacles - the tab on top and bottom are kind of big, to allow many attachment points. Usually, you only need the ones in the center, and the additional metal on the tabs frequently interfere with installation. However, they are designed to be broken off simply, because they are scored - simply grab the parts you don't want with a pair of pliers and bend back and forth until it comes off. Additionally, there are two of each silver and brass screws, so you can have each of the two sockets on an independent circuit. You want to do this if you want a wall switch to control one of the sockets and not the other. If you want to do this, you have to break off the connection between each pair of screw terminals.
- Attach the new receptacle. Black-insulation wire goes to brass screw terminal, white-insulation wire goes to silver terminal. I assume you are not stupid, and made sure that the insulation is sufficiently stripped to allow electrical contact with the inner wire and the screw terminal. You should be able to use the same part of the wire that was attached to the original two-prong receptacle. If the exposed part of the wire looks corroded or otherwise messed up, cut it off, and expose some more of the wire using the wire stripper. You only need to expose about 3/8 of an inch. Bend the exposed bit of wire into a loop to go around the screw.
- If you see a bare copper wire, that's the ground wire. It should be attached to the green screw terminal on the receptacle.
- Screw the unused screw terminals down, so they do not get in the way.
- As an extra precaution, you may want to cover up the screw terminals and the attached wires with a bit of electrical tape.
- Gingerly put the new receptacle into the receptacle box. There should be plenty of room for the extra length of wire. You may have to bend the wire to fold neatly.
- Screw in the receptacle to the box. If it goes too far into the wall, the cover will not attach properly. If this is the case, you'll have to shim it out with some washers.
- Attach the cover plate.
- Plug the circuit tester into the new receptacle.
- Flick the circuit breaker back on, or plug the fuse back in. Hopefully, you'll see that the receptacle is now powered with correct polarity and properly grounded. If the tester tells you that the polarity is reversed, you screwed the white wire into the brass screw terminal and the black wire to the silver terminal. Or perhaps whoever wired your house screwed up and reversed the wires. In any case, change the white wire to the black wire and vice versa. If you aren't properly grounded, make sure the bare copper wire is properly attached to the green screw terminal on the receptacle. If there is still a problem, you may have to test if the ground wire coming to your receptacle is properly grounded - which may be beyond the scope of this w/u.
- Now, go do the next one.
After this, you can go back to surfing the net with your properly grounded and polarized computer plugged into your new properly grounded and polarized receptacle.