4 ms·

It looks like only the 30 Amp plus NEMA connectors require ground to be on top. It does appear technically "safer". http://en.wikipedia.org/wiki/NEMA_connector

by dpitkin 14y ago

It looks like only the 30 Amp plus NEMA connectors require ground to be on top. It does appear technically "safer". http://en.wikipedia.org/wiki/NEMA_connector http://en.wikipedia.org/wiki/NEMA_connector

sc00ter 14y ago
Nope - the diagram on that page shows every current rating of NEMA plug with an earth pin at the bottom. I call bullshit on the whole "earth pin position as a safety measure" debate anyway. Copper wiring of any substance is physically to rigid to move, even if completely free of other mechanical constraints, so isn't going to "drop onto the live pins" no matter what, even if the internal arrangement of a socket facilitated it. (They - don't they're insulated, shrouded, separated etc.)
- X-Istence 14y ago
  This isn't for in the wall, but outside of it... For example you plug in a drill but it slowly works its way out, you are working with a screw driver against the wall and accidentally drop it, at this point the screw driver can come to rest on the live pins of the drill that is plugged partially into the wall. With the ground pins up the screw driver will pick a side and fall off...
  - dubya 14y ago
    You can try it yourself by dropping a bit of pencil lead across the prongs a slightly unplugged plug. You get a flash and it hops away, but I don't know that a piece of metal would break contact. I don't recall this ever even tripping a breaker, but be careful.
    - X-Istence 14y ago
      If you want a nice flash, take some low resistance half watt or even quarter watt resistors, place in power strip, plug power strip in ... Ah, so awesome.
- brudgers 14y ago
  [for the US] The longer ground pin at the top provides a mechanical advantage when a downward force is applied to the plug. Since this is the most common accidental force (e.g. something dropped or a cord on the ground dragged) it slightly reduces the risk of disconnect. In addition, the ground at the top allows for a better view of the pin and receptacle hole.
  - ars 14y ago
    The other way around. Plugs always fall out of ground up receptacles to the point that I will rewire them if I have any in my house. They hold nicely in ground down receptacles though. The insertion force of the one ground pin is lower than the two live ones. So when force is allied downward the plug pivots out of the receptacle. In a ground down orientation the plug will pivot into the wall. Since the ground pin moves easier than the other two, it moves into the wall instead of out.
- bhousel 14y ago
  This story of a kid dropping a tape measure down on a partially plugged in device seems somewhat credible: http://www.electriciantalk.com/f12/1st-hand-ground-down-story-14431/ http://www.electriciantalk.com/f12/1st-hand-ground-down-stor...
  - bburky 14y ago
    I once had a metal 18" ruler that fell off the back of a desk, and fell perfectly flush with the wall catching the top two prongs of an outlet. A spark, blackened the ruler and took a small notch out of it.

by dpitkin 14y ago

sc00ter 14y ago

Nope - the diagram on that page shows every current rating of NEMA plug with an earth pin at the bottom. I call bullshit on the whole "earth pin position as a safety measure" debate anyway. Copper wiring of any substance is physically to rigid to move, even if completely free of other mechanical constraints, so isn't going to "drop onto the live pins" no matter what, even if the internal arrangement of a socket facilitated it. (They - don't they're insulated, shrouded, separated etc.)

X-Istence 14y ago
This isn't for in the wall, but outside of it... For example you plug in a drill but it slowly works its way out, you are working with a screw driver against the wall and accidentally drop it, at this point the screw driver can come to rest on the live pins of the drill that is plugged partially into the wall. With the ground pins up the screw driver will pick a side and fall off...
- dubya 14y ago
  You can try it yourself by dropping a bit of pencil lead across the prongs a slightly unplugged plug. You get a flash and it hops away, but I don't know that a piece of metal would break contact. I don't recall this ever even tripping a breaker, but be careful.
  - X-Istence 14y ago
    If you want a nice flash, take some low resistance half watt or even quarter watt resistors, place in power strip, plug power strip in ... Ah, so awesome.
brudgers 14y ago
[for the US] The longer ground pin at the top provides a mechanical advantage when a downward force is applied to the plug. Since this is the most common accidental force (e.g. something dropped or a cord on the ground dragged) it slightly reduces the risk of disconnect. In addition, the ground at the top allows for a better view of the pin and receptacle hole.
- ars 14y ago
  The other way around. Plugs always fall out of ground up receptacles to the point that I will rewire them if I have any in my house. They hold nicely in ground down receptacles though. The insertion force of the one ground pin is lower than the two live ones. So when force is allied downward the plug pivots out of the receptacle. In a ground down orientation the plug will pivot into the wall. Since the ground pin moves easier than the other two, it moves into the wall instead of out.
bhousel 14y ago
This story of a kid dropping a tape measure down on a partially plugged in device seems somewhat credible: http://www.electriciantalk.com/f12/1st-hand-ground-down-story-14431/ http://www.electriciantalk.com/f12/1st-hand-ground-down-stor...
- bburky 14y ago
  I once had a metal 18" ruler that fell off the back of a desk, and fell perfectly flush with the wall catching the top two prongs of an outlet. A spark, blackened the ruler and took a small notch out of it.