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.