Why are some of the electrical receptacles (outlets) in my house upside down?

We’re used to seeing electrical receptacles (outlets) installed in a certain way…the ‘smiley face’ (see illustration 1). You may have noticed that some of the outlets in your house (usually one in each room – bedrooms, living room, etc.) are installed ‘upside down’ (see illustration 2). Why? Well, if properly wired, the top half of the outlet will be controlled by a switch (the bottom half should always be non-switched or ‘hot’). This is so you can plug a lamp into the outlet (again, top half) and turn it on/off with a switch (usually near the entry to the room). Why am I spending time writing about this you may ask? Well, it is quite often I go into a house and find switches taped in the down/off position and/or see notes on switches saying “Don’t turn off”. The reason? The home owner has plugged a computer or alarm clock or television into the top half of the upside down outlet and when the switch is turned off that item loses power. Frustrating! Well, little do they know that all they have to do is plug the item into the bottom half of the outlet, or another outlet, and they won’t have to worry about inadvertently turning it off. So why do they install the outlets upside down? That is so you can tell which outlet is controlled by a switch by looking at it. Also, just because you don’t have outlets that are turned upside down (older homes) doesn’t mean you don’t have switched outlets. Do a little detective work with a lamp. Go from outlet to outlet in a bedroom with all the switches ‘off’. You may find the top half (or in some cases the bottom half) of one outlet doesn’t have power. Now go turn the switch(es) on (one by one if multiple) and I’ll bet one of the switches controls that outlet. And so I don’t get emails from any ‘electrical purists’ out there, I know that technically the ‘smiley face’ outlet is installed upside down, but that is a topic for another day.