[PCR-1000] Grounding orientation

Tue, 19 Mar 2002 11:14:47 -0500

Hi Guys ... time for me to chime in with 2 cents worth ...

Most of the outlets I see are installed with ground pin down.

There are a lot of HD extension cords, like the short heavy ones for air
conditioners with right angle grounded plugs.  The cord is supposed to drape
down, not go up and the ground pin is on the bottom on most all of those
I've seen.  (Also have seen some diagonally oriented low profile plugs.)

Most wall warts are designed  to hang downward also.  Usually they're just
two prong, but often polarized.  When the outlet is upside-down, they hang
precariously as if about to fall out of the outlet.  (and provide a very big
bobby pin grabber)

I do see a lot of outlets installed ground pin up.  Actually, from time to
time, I've had to install them that way, myself.  If the outlet is a new,
grounded replacement for an old two prong non-polarized outlet.  In old
construction, the hot and neutral might be oriented any which way -- made no
difference to them back then.  Often, the wires are too stiff and short
(maybe cut down once before) to cross over and still allow installation of
the new outlet -- hot and neutral are backwards relative to the silver and
brass terminal screws. So, you have to flip the outlet to preserve proper
hot/neutral polarity (small/big slot).

So, if you see and "upside down" outlet, it may be because of that.  True,
most of the newer grounded outlets have quickie push-in connector holes in
the back, but that usually involves straightening the hook in the old wires
(might break), or clipping & stripping, making them still shorter. (I don't
feel comfortable with those quick connector things.)

Another issue -- more important that groundlug down/up is how that "ground"
is grounded.  Most grounded outlets have the mounting tabs connected to the
ground lug terminal and sometimes that's the only connection via the "gem
box".  Old construction might involve armored 2-conductor BX cable where the
armor shell is the ground connection.  That depends on the quality of the
connection at the cable clamp going into the box and a rather tenuous
connection between the mounting screw, the tab and the gem box.  With newer
construction you might have plastic gem boxes and grounded "romex".  Or you
might have aluminum wire -- which is another problem.

Point is -- check the quality of the ground as well as the polarity of the
socket.  Those little plugin testers (two greens is good) jobbies are
helpful, though you can do the same with a voltmeter.  However, the testers
will show good even though there's resistance to ground due to a bad
connection.

BTW - about the bobby pin thing.  With an upside down (ground pin up)
installation, and a not fully seated plug, the bobby pin could well strike
the ground lug first and then slip sideways and short to the hot prong.
(Murphy's Law would dictate the hot, not the neutral.)  With ungrounded
plugs, makes no difference.  So I'd rather doubt there's any code on that.
Instead I'd recommend:  1 -- plug your lamps and appliances all the way in
flush. and 2 -- watch out for those bobby pins and other little metal stuff.

Barry

----- Original Message -----
From: "Pres Waterman" <[email protected]>
To: <[email protected]>
Sent: Tuesday, March 19, 2002 10:10 AM
Subject: Re: [PCR-1000] Grounding orientation

> > Actually, there is a reason for duplex plug receptacle to be oriented
> > with the ground pin down.   It is called "make first break last"!   One
> > wants the ground of an electrical circuit to be the first thing
> > connected and the last thing disconnected.    Gravity being what it is
> > and the pulling down on a cord may cause a plug's hot and neutral pins
> > to expose but the ground should still be connected.    Inverted the
> > ground would disconnect first making an unsafe circuit.
>
>
> Notice the ground pin is longer
>
> Pres Waterman, W2PW
> c/o Patchogue 112 Ford//Kia 112
> Long Island Ford and Kia Dealer
>
> GO BILLS!
>
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