Curiosity about American 3-pin outlets.

[Syncopator]

Until some years ago American 3-pin outlets were installed similarly to ours insofar as the earth pin was at the top; presumably for the same reason that ours are.


Now, though, they all seem to be installed with the earth pin at the bottom.


Does anyone know the reason for this?

 

[Sintra]

US receptacles are made up of a grid type system with separate cover plate so could easily be fitted with the Earth pin up or down. I've checked through my pics from a job I was on on the states a few months back and all earth pins are at the top. The other thing with US receptacles is that they are still designed to accept 2 pin plugs meaning that the live pins aren't shuttered like the UK version.

 

[Syncopator]

Thank you Sintra.

Strange. I see many recent photographs in which receptacles are mounted with the earth pins are at the bottom.

As an aside, there's a local franchise of a well known coffee shop were there is an upside-down 13A socket mounted at counter/work surface height!

 

[Gardner]

Its always been either up or down. In homes usually down, but in commercial often up with the thinking if the metal cover falls on the pins it hits the earth pin. Nothing in code (NEC) requires one or the other.

 

[norcal]

Thank you Sintra.

Strange. I see many recent photographs in which receptacles are mounted with the earth pins are at the bottom.

As an aside, there's a local franchise of a well known coffee shop were there is an upside-down 13A socket mounted at counter/work surface height!

The NEC code committee's have refused to touch the issue of ground prong up, or down, and any American electrical forums will lock any threads on the issue, it is purely personal preference or job specs that dictate which way, up, or down, then you can add to the discussion in area's like Chicago that do not allow any flexible wiring methods like Non- Metallic Sheathed cable (NM), or Metal Clad cable (MC), so everything is EMT, Electrical Metallic Tubing, which some call thin wall conduit, and the preference for some is horizontal mounting of receptacles, then you can add to the debate if the neutral on the device is up or down.

Edit: when EMT is used with 4X4 metal boxes, it is a simple matter to turn the plaster ring 90 degrees to have either vertical, or horizontal mounting.

 

[gnuuser]

US receptacles are made up of a grid type system with separate cover plate so could easily be fitted with the Earth pin up or down. I've checked through my pics from a job I was on on the states a few months back and all earth pins are at the top. The other thing with US receptacles is that they are still designed to accept 2 pin plugs meaning that the live pins aren't shuttered like the UK version.

there are receptacles that shutter both pins but they are not popular with many folks yet.
I like to install them when i know the home owners have small children (if they want them)
i also like to install the earth pin up as well but many guys like to argue the point on it

 

[norcal]

there are receptacles that shutter both pins but they are not popular with many folks yet.
I like to install them when i know the home owners have small children (if they want them)
i also like to install the earth pin up as well but many guys like to argue the point on it

Tamper resistant receptacles are required in dwelling units per section 406.12(A) of the National Electrical Code.