This is something that I have always wondered about. In ICI you often and almost exclusively see receptacles ground up. As the story goes it's to stop objects from sliding down an contacting the live prong of a poorly inserted plug.

The Canadian Electrical Code makes no reference to the "correct" orientation but shows the image of a receptacle ground pin up. But hot wires are supposed to be on the right bottom terminal first(I've been told). Why the discrepancy between industrial and institutional vs residential? Commercial goes either way, but if it's inherently safer ground up why are receptacles manufactured to be ground down and why is residential ground down? Over the years I've discussed this with many electricians of various backgrounds and have got a lot of different answers. Hoping to get something concrete here.

  • what does this mean? But hot terminals are supposed to be on the right bottom terminal first. ..... and this receptacles manufactured to be ground down? – jsotola Feb 26 '19 at 5:34
  • In discussion with electricians my interpretation of what I have heard is, that hot wires should be on the right side of switches and recepticals going to the bottom terminal first. I don't know if that's just a common practice or if it is in a code. I know it doesn't apply to 3 and 4 way switchs.. And looking up at my question it should read "but hot wires are supposed to be on the right bottom terminal first" sorry I will correct that. – Joe Fala Feb 26 '19 at 5:52
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    There's no difference, usually outlet are fitted upside-down to indicate in an easy way that controlled by a switch, but it's only a common use and not mandatory. – DDS Feb 26 '19 at 9:00
  • In commercial applications the ground post is on top for the reason that you stated. Safety! In residential the ground is on the bottom because people don't like to change. So it is just a generally accepted practice. The hot terminal on receptacles is where it is to meet the standard NEMA configuration for the plug. And well, single pole switches have the terminals on the right so that up corresponds with the on position. – user68386 Feb 27 '19 at 0:02