Most people think of electrical outlet receptacles as being properly installed when the two vertical slots are at the top, with the round grounding hole at the bottom. You may, though, see many installations that seem "upside-down," where the round grounding hole is at the top, with the vertical hot and neutral slots at the bottom.
In reality, there is no code requirement that says an outlet receptacle should be installed one way or the other. In fact, at one time some manufacturers actually recommended the orientation that many of us view as upside down—with the round grounding slot at the top. Many electricians still prefer this type of installation.
Unlike wall switches, outlet receptacles do not have an up or down and will work just fine installed in either position. The only problem is really just one of expectation and convention. Since outlets are more commonly installed with the ground holes on the bottom, it can be oddly disturbing to some homeowners if they perceive their outlets as being installed contrary to standard practice. But once you understand the reasons why it was done, you may want to leave them in place—or even change all your receptacles to be "upside down."
Advantages of "Upside-Down"
The National Electrical Code does not stipulate how outlet receptacles should be positioned within the electrical boxes. But some electricians install the receptacles with the ground slot facing upward, for several reasons:
To Identify a Switch-Controlled Outlet
Your outlet might turn on or off by a wall switch. This is valuable when you have a floor lamp you want to turn on when you enter a room. Some electricians will turn this outlet receptacle upside-down as a quick visual cue to indicate a switch-controlled receptacle. If your home has only one or two upside-down outlets, this may have been done as a means of identifying switch-controlled outlets.
To Promote Better Electrical Safety
Some people believe that this upside-down position reduces the possibility of electrical shock. In an upside-down position, if a three-prong plug comes partially out of the receptacle and a metal object should accidentally fall between the outlet faceplate and the plug, the object will first hit the grounding prong. In the normal (grounding slot down) position, there exists the possibility of a short circuit if an object falls into this space and bridges the gap between the hot and neutral prongs.
This is the logic that led some receptacle manufacturers to recommend this as the preferred orientation for receptacles. In hospitals, you usually see all wall receptacles installed this way as a safety measure since a short in a circuit that powers a ventilator or other medical device can be a very serious matter.
To Give Plugs a Better Grip
Some electricians and homeowners believe that a three-prong plug installed in this fashion holds tighter in the outlet. This point has some validity, but with the advent of TR (tamper-resistant) outlets, this point may soon become moot, as TR outlets provide a very strong grip on fully inserted plugs. Unfortunately, TR outlets have the opposite effect on partially inserted plugs, as the spring-loaded internal doors tend to push plugs out.
When to Call a Pro
If you have any misgivings about opening up an electric outlet, call an electrician to do this task. Even though this is a very easy project, electricity is dangerous if not handled properly. Any DIYer who is nervous or uncertain about making a basic electrical repair is well-advised to have a professional do the work.
Equipment / Tools
- Non-contact circuit tester
- Flathead screwdriver
- Cordless drill
If you find your upside-down outlet to be visually disturbing, or if you feel that one of the above reasons is a good reason to mount them ground-slot-up, it is quite easy to change their orientation. It will cost you nothing to do so.
Turn the Power Off
Go to your electrical service panel and turn off the circuit breaker that controls the circuit feeding the outlet.
At the outlet, test for power using a non-contact circuit tester. Before use, make sure you understand how the tool works, and that its batteries are charged.
Remove the Outlet Faceplate
Once you have verified that the power is shut off, remove the faceplate on the outlet by removing the mounting screw. There should only be one screw to remove with most outlets.
Extract the Receptacle
Remove the top and bottom mounting screws that hold the outlet strap to the electrical box. Carefully gripping the metal strap, gently pull the receptacle out of the box so that the wires nearly straighten out. Be very careful not to loosen any of the wire connections. Most outlets have enough wire to allow them to be pulled several inches out of the electrical box.
At this time, it is always a good idea to check with the voltage tester to make sure that no power is flowing to the outlet.
Rotate the Outlet Receptacle
Gently rotate the receptacle around 180 degrees so that it is now right-side-up. Be very careful to avoid dislodging any wire connections as you rotate the receptacle. If you find the receptacle hard to rotate due to short wires, then it is best to completely disconnect the receptacle, rotate it, then reconnect the wires to the screw terminals.
Tug gently on the wires to verify that the wire connections are still secure on the outlet's screw terminals.
Insert the Receptacle
Carefully tuck the circuit wires back into the electrical box and press the receptacle into the box. Usually, it is easiest to fold the wires rather than randomly stuffing them back into the box.
Thread the mounting screws on the device strap back into the screw holes on the electrical box, and tighten them down securely, making sure the outlet is perfectly vertical. Reattach the outlet faceplate.
Test the Outlet Receptacle
Turn on the power at the circuit breaker, then test the receptacle to make sure it operates correctly. This can be done with the circuit tester, or by plugging in a lamp or other small appliance.