Why does a two prong recepticle have a ground screw?

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kwired

Electron manager
Location
NE Nebraska
Yoke serves as the ground point. Remember the little green wire with the spade terminal that was supposed to go under the plate screw?
Yeah and I have seen them under the plate screw on receptacles that still had no equipment ground anywhere in the outlet box. Talk about misleading people that don't know what they are doing in the first place.

About the only time an equipment ground is present where a two wire receptacle had been originally installed is where a metal raceway was serving the receptacle installation and was a complete raceway back to the point where the circuit originates.

Back to the OP I don't recall ever seeing a 2 wire receptacle with an equipment ground screw. I can picture a newer one having one just because they may use same yoke used on grounding receptacles to construct the non grounding ones. It may not have been intended to install a screw in the space where it goes. Seen many non grounding switches with the spot where a grounding screw is supposed to go probably for the same reason - they used the same yoke as grounding switches use.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Electrical Contractor
I haven't seen any either however I still have some from 10 or more years ago.

I bet they use the same yoke for both receptacles rather than change. Surprised they would put the screw in but it may be cheaper then changing the production.
 

220/221

Senior Member
Location
AZ
Why does a two prong recepticle have a ground screw?
The same reason men have nipples.

It makes more sense to have one basic design and tweak it with a few simple changes to create different models.
 

jaylectricity

Senior Member
Location
Massachusetts
About the only time an equipment ground is present where a two wire receptacle had been originally installed is where a metal raceway was serving the receptacle installation and was a complete raceway back to the point where the circuit originates.
A situation I see quite a bit of around here is old NM with the ground wrapped around the edge of where the jacket is stripped. Then that part of the cable is fastened underneath the clamps entering a metal box. Then a two-prong receptacle was installed.
 

mivey

Senior Member
I bet they use the same yoke for both receptacles rather than change. Surprised they would put the screw in but it may be cheaper then changing the production.
I like the same yoke theory also. I just can't magine that a production run would leave in the screw. It seems small, but that is real $ in large quantities.

Zappy: where did it come from?
 
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