stranded wire & screws

templdl

Senior Member
Location
Wisconsin
I have seen brass plates that look like this but they do move. Guess we need actual part number to know for sure. Your closeup shows the brass is not a 'flat' plate, it definitley has a groove in it under the screw. This is for trapping some type of wire.
It is of my opinion that the wire is on top of the plate, that is between and the screw head where the screw should actually be lostened to a point where the wire can be inserted under the plate and wire alligned with the channel on the bottom side of the plate. The screw is tightened down securing the plate against the wire.
I would also confirm that the device is listed for terminating the wire that is being used.
 

jumper

Senior Member
I have seen brass plates that look like this but they do move. Guess we need actual part number to know for sure. Your closeup shows the brass is not a 'flat' plate, it definitley has a groove in it under the screw. This is for trapping some type of wire.
It is of my opinion that the wire is on top of the plate, that is between and the screw head where the screw should actually be lostened to a point where the wire can be inserted under the plate and wire alligned with the channel on the bottom side of the plate. The screw is tightened down securing the plate against the wire.
I would also confirm that the device is listed for terminating the wire that is being used.
I do not think that is a pressure plate for the EGC termination. While receptacles do exist with that design, that does not seem to be one.

Here is a spec print of a pressure plate EGC terminal. Notice the slot rail behind the plate for insertion of the conductor.

 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
I repaired several of these on that particular job and Bob is correct there is no plate. I posted the photo to show because IMO a #10 stranded should not be wrapped around a screw. Even a more professional installation may lead to problems. Something like this was only discovered because that was an IG ground and some of the strands were in contact with the yoke.
 

kwired

Electron manager
Location
NE Nebraska
There are some terminals that have a hole in the back surface right near the screw. If you have this place end of stripped conductor in that hole and wrap CW around screw, then tighten screw. Works very well, and would be nice if all screw terminals had this feature.
 

S'mise

Senior Member
Location
Michigan
I always use Sta-kon lugs if the device does not have pressure plates. Stranded wires under a screw are not a tight connection (imo), and usually end up with cat-whiskers sticking out.

The white book listing that Don wrote is interesting. Does that mean Its OK to land a stranded wire on a screw of a receptacle, but not a switch?
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
...The white book listing that Don wrote is interesting. Does that mean Its OK to land a stranded wire on a screw of a receptacle, but not a switch?
That is exactly what it means.

Also note that the instructions provided with some receptacles say to only use solid conductors, but I don't know how that works. It seems that the listing standard says that the screw terminations have to be suitable for use with stranded conductors, if the receptacle is a listed receptacle.
 

Besoeker

Senior Member
Location
UK
Don't you guys use ring crimp terminals like this:



That would avoid the messy job shown in post #11.
 

norcal

Senior Member
The device screws are not intended to be removed from the device, so if crimp terminals are used, they would normally be forks and not rings.
Are crimp fork terminals allowed to be used w/ switches & receptacles since I have heard conflicting opinions that it is not allowed & that it is .
 

Besoeker

Senior Member
Location
UK
The device screws are not intended to be removed from the device, so if crimp terminals are used, they would normally be forks and not rings.
OK. Surely forks would be a better option than bare twisted wires?

It isn't generally an issue that comes up here in UK. Nor wire nuts. Pretty much everything is fitted with brass screw type terminals.

 

templdl

Senior Member
Location
Wisconsin
That is exactly what it means.

Also note that the instructions provided with some receptacles say to only use solid conductors, but I don't know how that works. It seems that the listing standard says that the screw terminations have to be suitable for use with stranded conductors, if the receptacle is a listed receptacle.
As I stated in my post #7.
 

Smart $

Esteemed Member
Location
Ohio
Are crimp fork terminals allowed to be used w/ switches & receptacles since I have heard conflicting opinions that it is not allowed & that it is .
I don't think that they are disallowed, but rather not UL (NRTL) evaluated or tested for use with receptacles and switches being discussed here.
 
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