Install outlets (receptacles) with the ground hole either up or down. Both are correct. But be consistent.
By the DIY experts of The Family Handyman Magazine
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Ground hole up or down?
Photo 1: Ground hole up
Have you ever wondered if you have upside down outlets? The electrical code allows outlets to be installed with the ground plug hole facing up, down or sideways. It’s up to you, there is no standard electric outlet orientation. So that means there really is no such thing as upside down outlets.
Photo 2: Ground hole down
The ground hole is in the down.
You usually see outlets installed with the ground hole down (Photo 2). But it’s no better than installing them the opposite direction (Photo 1). Electricians endlessly debate this and vigorously exalt the virtues of installing it one way or the other, but we’ll tell it to you straightit just doesn’t matter. Both ways are correct. The electric code doesn’t specify which direction the ground plug hole needs to face. One way isn’t safer than the otheras long as the outlet is wired correctly.
It all comes down to aesthetics, so install them whatever way looks best to you. Incidentally, the ground plug is typically down in the United States, the opposite of how it’s generally installed in Canada.