Consequences of having on the receptacle box (not the outlet itself)grounded.

I was looking at the wiring in my parent's house and i noticed a couple of 3 prong outlets where the ground wire was only attatched to the metal receptacle box (by a screw) but not connected to the grounding screw of the outlet itself.
I don't believe, but i didn't test it, that there is any sort of 'self grounding clip' or anything which connects the grounding screw of the outlet to the box thus making the outlet grounded as well. But i guess i could have missed it.
Assuming that it resally is as i initially thought, box is grounded but outlet is not, is this a normal occurence at all or an example of wiring that needs to be fixed?
It is not a GFCI outlet nor is it protected by a GFCI outlet.
Thanks for any replies.
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kevins_news2 wrote:

You can buy a wire pigtail that clips on the metal box so you can ground ordinary outlets, or you can buy "self-grounding" outlets that have a little flat copper spring on one of the mounting holes -- it will make good electrical contact with the box even if the screw is not as tight as it ought.
Bob
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The mounting arms of the outlet serve as the ground connection. The outlet is grounded through the metal box and conduit.

Yep, there is a clip, which goes on the mounting screws which insures they are electrically connected, even if the screw is loose. I've seen them on new outlets, I don't think they are available separately.

Again, the metal mounting arms of the outlet are connected to the ground terminal. The screw lug connection is only needed if you want to connect a ground wire to the outlet.
As long as you have a good mechanical connection to metal box and conduit, the outlet is grounded.
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wrote:

Thanks. I didn't realize that the mounting arms of the outlet were common with the ground terminal screw. For a moment this made me wonder why there was a screw but i guess if you have one of those plastic boxes then you'd have to use the screw.
Kevin
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I don't buy it. I have never found a receptacle that was bonded satisfactorily to the box. If you want safety and reliability without trying to save 60 seconds of time, do it the right way. Wire the box AND the receptacle to a wirenut to ground.
On Fri, 16 Jul 2004 15:10:00 GMT, kevins_news2

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Sounds like someone was in a hurry, and wasn't doing it for themself. Nothing better than a direct connection, rather than relying on a secondary one, that might become loose, oxidize, or whatever. If it were me I would redo them all to be hard wired.
On Thu, 15 Jul 2004 20:04:49 GMT, kevins_news2

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