OK - I've read the bitter vitriol in here used to describe the use of the
push-in option when wiring electrical outlets, but is there any study
someone can point to that has tested the long term difference between the
screw terminals and the push-in variety? All I hear is anecdotal - kinda
like the resistance a few have for using PEX in plumbing.
Aside from 'personal experience', is there any data?
I think NEC banned 'stab' connections on outlets used with 12ga wire. I
don't know what data they used if any to make that change.
I always use 12ga 20Amp circuits. When I come across any 'stabbed'
outlets or switches I will go ahead and pull the wires out and use the
screws. I can never seem to make the release things to work so I end up
pulling hard while twisting back and forth.
If you do use the 'stab' connectors then I would use pigtails.
I prefer to use the 'back-feed' type where you put the wire in the hole
and tighten the screws. I am comfortable using those without pigtails.
The back feed type do cost more though, over $2.00 each.
I would think the real world experiences of thousands of people and tens of
thousands of outlets would consitute 'data'. It's been proven over and over
that the pushin connection is unreliable especially when in the middle of a
'series' run of outlets. I use them very rarely and only on a single
switch. I never use 14 ga on outlets so it's a moot point on them.
I don't know about statistical data but just law od physics.
It may be quick and easy method but look at the contact area of
the wire vs. looping wire around screw and tightening it.
Spcially when the outlet is carry near capacity current.
I never wired using stab method. But I am sold on PEX.
Jolt is a function of voltage, not current. Across car battery, not much
jolt.Current is a function of contact area or size of wire. Like thicker
wire has more current carrying capacity. If frequency of current goes
way high into R.F. range, skin effect comes into play. That is why R.F.
carrying conductor is some times hollow pipe or multi strand wire(Litz
wire), not solid core wire.
I am retired EE who used to work on mega size telecomm/computer site. On
mil-spec wiring, I never observed stab wiring. Probalby commercial
wiring is same.
In electronics when wanting to ensure a good signal or clean power
there are several fundamentals that must be observed. However when in
doubt the old adage "more copper" comes to mind. If there is less
surface area for current transfer from one conductor to another then
resistance will build and that translates to heat. The stab type
outlet has far less surface area in contact with the wire than the
screw type does. This in itself is a dangerous design when you use
devices that require much current draw from that outlet. I don't think
it's a matter of how secure the connection is rather than the contact
areas between the wire and outlet that are in question.
"My sources are unreliable, but their information is fascinating." ~
On Sat, 15 Dec 2007 22:19:07 -0500, "badgolferman"
And yet, UL approves the "stab" outlets.
I would presume they do all sorts of controlled lab tests.
Their approval seal "should" be better than any folklore.
How about the Canadian testing group ?
They tend to be more conservative.
Do they approve "stab" outlets ?
Yep, In the last house I lived the wife always used the same
receptacle to plug the vacuum into. I plugged something in one day
and a heard what sounded like a spark/sizzle sound. Pulled the cover
plate and receptacle too find burn marks at one wire on the back stab.
UL listing means exactly what it says on the listing and labeling. It
complies with the standard that applies to that labeling. UL does not
write the standard they just test to the standard. If the standard is
inadequate don't blame UL.
???They are UL standards developed by or under the leadership of UL. UL
lab's reputation depends on the effectiveness of the UL standards.
Some standards may not determine if a device actually works. A lot do -
fuses, GFCIs. IIRC receptacle tests include 150% of rated current.
Receptacles should 'actually work' - except for the backstab feature. I
can't understand how that is allowed by the standard. Other than
backstabs receptacles are pretty reliable.
In addition to contact area, another problem is contact pressure.
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