I have a number of outlets that are old and worn out (plugs fall out of them mainly.)
Obviously I need to turn off the breaker to replace them safely.
Any guidance on how to rewire them, how to properly ground the new one, and how to safely test them once the power is back on?
If you plan on doing much electrical work around the house, get a multi-meter. It's just a little box with black and red probes on the end. Safe enough to stick in an outlet to see if it's live or not.
Outlets are mostly idiot proof. Turn off the breaker, pull it out of the box, see where the old wires are attached and move them one by one to the new outlet. Probably the old outlet already has a ground wire, in which case you're done. If it doesn't, it's probably time to call a pro.
Once you have it hooked up and the power is back on, you can use the multimeter to test. There is a hot side and a neutral side to the outlet. Ground behaves the same as neutral as far as the multimeter is concerned. You should be able to stick one prob in the hot side and the other into ground or neutral and get around 110 on the multimeter (+/- 2-3 volts).
One other very important thing that nobody has mentioned: before purchasing your replacement outlets, make sure that your house does not have aluminum wiring.
Most of the switches & outlets you'll find are designed for copper, and using them with aluminum can lead to dangerous conditions, including fires. There are outlets specifically designed for aluminum.
Something like this (not this) should show you quickly if your current plugs are wired correctly, and should also test the ground. If you've got a good ground, then replacing the socket should be just a matter of:
If you don't have good ground, then you might not have a ground wire running into the box, which makes this alot harder, and you might want to call a real electrician at that point.
Another thing not mentioned so far: tamper-resistant receptacles are required by code in the US (since 2008) and Canada (since 2009). These have a built-in plate that covers the holes unless something is pushed into both sides at once, which greatly reduces the chances of a child pushing something into an outlet and being injured.
Big box stores will still have the old kind on-hand (it's not illegal to sell them, and AFAIK they can still be used in non-residential environments), so be sure you get the right ones if you want to do the work to code and have the most up-to-date safety features.
Other people have already answered this one pretty well. I just wanted to add one thing. While you are replacing the outlets, it might be a good idea to use GFCI receptacles where appropriate.
GFCIs should be used wherever stuff that is plugged into it could be exposed to water. (Outlets that are near kitchen/bathroom sinks, outdoor outlets, outlets that are right under a water line, etc).
Note: in some jurisdictions (e.g. Australia), it's illegal to do your own wiring - you have to use a licensed electrician.
One very important thing that others have not mentioned - If the outlet is in a kitchen in an older home, it will often have separate circuits for the top and bottom plug.
So, if that's the case, make sure BOTH circuits are off, and when you put the new outlet in, make sure you break off the little tab that connects the top and bottom wire connectors on both sides of the outlet (note that you ONLY do this if there are two circuits on the outlet. Leave the tab on if there's only one)
