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Joined: Dec 2000
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I mailed one of these Zinscos anonymously to NORCAL to horrify him. [This message has been edited by electure (edited 01-07-2007).]
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Joined: Mar 2004
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I must be in the picky minority here because I don't like backs-stab or back-wire receptacles. Even when applying serious torque to back-wire receptacles, I've had the wire come loose under the pressure-plate when I went to push everything into the wall. Consequently, I end up torquing back-wire receptacles twice to guarantee a solid connection.
I've never once had a loose connection with a screw-terminal receptacle so I prefer to use those.
-John
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Joined: Aug 2005
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Shake n Bake
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Joined: Oct 2002
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It worked on me Electure!
I still see those evil beasts on some older apartment buildings (and in my nightmares!).
Shame on Zinsco! Shame!
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Joined: Oct 2004
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Joined: Mar 2005
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We had some other pictures posted in the general forum. The back-stab design is completely sound and actually has very good surface area! The key is that the wire must be STRAIGHT and installed properly. If the wire is kinked or too short or otherwise poorly installed then, yeah, you're going to have a fire risk. Why not post pictures of screw terminals that have been put on backwards or with too loose or a loop, or too short so the insulation is trapped and a poor connection made? https://www.electrical-contractor.net/ubb/Forum1/HTML/007963.html Steve Fehr: The infamous back-stab revealed! This is (was) a Leviton 15A 120V light-duty light switch. Honestly, there's a surprising amount of contact area in there- there is a dimple sized for #14, and a large spring to hold it in place. The wire would have to be as straight as possible, though, or else it might only contact at 1 or 2 points instead of along the length. But installed properly, 3/8" of the wire will have contact along about 180° of circumference. Edit: it's stamped MADE IN USA, btw Theelectrickid: [This message has been edited by SteveFehr (edited 03-04-2007).]
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Joined: Nov 2000
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If stabs are so good, why do you only see them on the lower quality devices? Honestly, there's a surprising amount of contact area in there- there is a dimple sized for #14, and a large spring to hold it in place. The spring is only a single strip and only provides solid contact pressure at that point. Don
Don(resqcapt19)
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Joined: Mar 2005
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The spring is providing pressure, and holds the wire against the contact area the same way a screw would. The biggest difference is that it provides less pressure; a screw terminal will straighten out a bent wire, while the spring in the stab will merely hold it in place.
If installed properly, there is nothing wrong with a stab and it works fine and dandy and no buildings burn down and everyone is happy. It's if the stab is not installed properly that we see problems- and, unfortunately, it's impossible to inspect and verify the quality of these connections.
My feeling is that the stab is good in theory but unsafe in practice unless very careful care is taken.
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Joined: Apr 2004
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The link in Steve's post to my Photobucket Dissection doesn't work, so here's a new one: https://s29.photobucket.com/albums/c266/Macsignals/Electrical%20Stuff/ For me: If someone uses them along with saying "Get 'em done NOW NOW NOW!", then I hate them. If someone actually takes the time to cut the wire off, strip it the right length and stick it in, then OK, I won't argue. Ian (Screw 'em down!) A.
Is there anyone on board who knows how to fly a plane?
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Joined: Nov 2000
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Steve, The spring is providing pressure, and holds the wire against the contact area the same way a screw would. The biggest difference is that it provides less pressure; a screw terminal will straighten out a bent wire, while the spring in the stab will merely hold it in place. The area of "contact" pressure provided by the screw is hundreds of times greater than the area of "contact" pressure provided by the flat spring. Don
Don(resqcapt19)
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Joined: August 2007
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