In my experience, electrical tape loses its stickiness long before
any other component in an electrical installation would otherwise fail or
need to be replaced. I don't have lots of faith in electrical tape for any
long-term role of importance and try to avoid using it for anything other
than holding a cable onto a snake.

"Nate Nagel" wrote in message
...
just wrap a turn of electrical tape around the recep in a tight box

nate

Andrew M. Saucci, Jr. wrote:
One advantage of a backstabbed connection is that if the end of
the conductor is carefully trimmed, none of the conductor is actually
exposed inside the box. That can reduce the chance of a short, especially
in a metal box or where a bare grounding conductor is present. This would
be a particular advantage if screw terminals were not present at all
(uncommon these days).

Screw terminals can be dangerous too if they are over tightened
or under tightened, or if the conductor is poorly trimmed.

"David Nebenzahl" wrote in message
.com...
I'm here to say that the conventional wisdom that one gets here--that
"backstabbed" wiring is bad, evil, and always leads to failure--may not
be correct.

[To the perplexed, "backstabbed" means that instead of using screw
terminals to connect wires to devices such as outlets and switches, the
stripped (solid) wire is pushed into a connector that grabs the wire
inside the device. Very commonly used "in the field".]

The opinion one reads here most often is that this is an inferior wiring
method that must always be suspected when there are electrical problems,
that it should be avoided and that it should be corrected if found.

I'm not sure that's correct.

First of all, it is an approved, UL/CSA tested, and, most importantly,
code-approved (US building code) wiring method. If it was as all-fired
bad as folks here claim, why would it still be allowed? After all, the
building codes tend to err on the side of caution.

My own experience, as limited as it might be, has not shown backstabbed
connections to be the source of any trouble. I recently worked on a
house built in the 1960s in which all devices were backstabbed. I was
called to add a circuit, not to correct any problems. There was no
current problem with any device that I could see, nor was there any
history of any such problems.

I'd like to see some more evidence for the badness of backstabbed
connections. Everything I read here is either based on anecdotal
evidence, or just speculation and personal preference.

I will say that I personally don't like backstabbed connections; as
tempting as they are (a lot faster than
stripping/bending/screwing/crimping using screw connections), I prefer
the "old-school" method. But I do think they've gotten an unfairly bad
rap. Furthermore, I refrain from automatically correcting them
(replacing backstabbed connections with screwed ones) when I see them,
on the theory of "if it ain't broke, don't fix it", and I suggest this
to others. Especially newbies and DIYers; I think it's bad advice to
automatically suspect backstabbed connections as the source of a fault,
and to imply that they should all be ripped out and redone.

Let the brawling commence.


--
Found--the gene that causes belief in genetic determinism





--
replace "roosters" with "cox" to reply.
http://members.cox.net/njnagel

The 50 cent Jap Wrap doesn't last, the 3 dollar per roll 3M tape lasts
a very long time.

Of course the foreman acts like he is giving you a kidney when he
gives you a roll.


On Wed, 19 Aug 2009 22:42:06 -0400, "Andrew M. Saucci, Jr."
wrote:

In my experience, electrical tape loses its stickiness long before
any other component in an electrical installation would otherwise fail or
need to be replaced. I don't have lots of faith in electrical tape for any
long-term role of importance and try to avoid using it for anything other
than holding a cable onto a snake.

"Nate Nagel" wrote in message
...
just wrap a turn of electrical tape around the recep in a tight box

nate

Andrew M. Saucci, Jr. wrote:
One advantage of a backstabbed connection is that if the end of
the conductor is carefully trimmed, none of the conductor is actually
exposed inside the box. That can reduce the chance of a short, especially
in a metal box or where a bare grounding conductor is present. This would
be a particular advantage if screw terminals were not present at all
(uncommon these days).

Screw terminals can be dangerous too if they are over tightened
or under tightened, or if the conductor is poorly trimmed.

"David Nebenzahl" wrote in message
.com...
I'm here to say that the conventional wisdom that one gets here--that
"backstabbed" wiring is bad, evil, and always leads to failure--may not
be correct.

[To the perplexed, "backstabbed" means that instead of using screw
terminals to connect wires to devices such as outlets and switches, the
stripped (solid) wire is pushed into a connector that grabs the wire
inside the device. Very commonly used "in the field".]

The opinion one reads here most often is that this is an inferior wiring
method that must always be suspected when there are electrical problems,
that it should be avoided and that it should be corrected if found.

I'm not sure that's correct.

First of all, it is an approved, UL/CSA tested, and, most importantly,
code-approved (US building code) wiring method. If it was as all-fired
bad as folks here claim, why would it still be allowed? After all, the
building codes tend to err on the side of caution.

My own experience, as limited as it might be, has not shown backstabbed
connections to be the source of any trouble. I recently worked on a
house built in the 1960s in which all devices were backstabbed. I was
called to add a circuit, not to correct any problems. There was no
current problem with any device that I could see, nor was there any
history of any such problems.

I'd like to see some more evidence for the badness of backstabbed
connections. Everything I read here is either based on anecdotal
evidence, or just speculation and personal preference.

I will say that I personally don't like backstabbed connections; as
tempting as they are (a lot faster than
stripping/bending/screwing/crimping using screw connections), I prefer
the "old-school" method. But I do think they've gotten an unfairly bad
rap. Furthermore, I refrain from automatically correcting them
(replacing backstabbed connections with screwed ones) when I see them,
on the theory of "if it ain't broke, don't fix it", and I suggest this
to others. Especially newbies and DIYers; I think it's bad advice to
automatically suspect backstabbed connections as the source of a fault,
and to imply that they should all be ripped out and redone.

Let the brawling commence.


--
Found--the gene that causes belief in genetic determinism





--
replace "roosters" with "cox" to reply.
http://members.cox.net/njnagel

E Z Peaces wrote:
Robert Green wrote:

Newbies and wire nuts don't mix well, either. Stripped end of wires too
long, too short, wrong size nut, wrong mix of wires, twist not twisted
enough. There's no end to sad tales with wire nuts in the hands of the
inexperienced. My favorite is three wires under one nut with a virtually
untwisted center wire that pulls right out on the first tug. I am
much more
concerned with bad wire nutting than with backstabbing.

--
Bobby G.


The connection would probably have been strong if all three wires had
been virtually untwisted. When John Blomstrand filed to patent the wire
nut in 1950, that was his intent. If wires are straight and solid and
of equal gage with even ends, I suppose the threads of a wire nut should
engage every wire in a bundle of as many as six, mashing them together
with no wiggle room.

Thirty years ago it was apparently common for electricians to use wire
nuts badly, twisting wires together clockwise before twisting on the
connector clockwise, then hoping tape would hold everything in place.
I've redone many.

I love wire nuts even for conductors of dissimilar gages and stranded
conductors, each of which may make it trickier to use wire nuts. Nearly
40 years ago, I installed a fairing on my motorcycle, which entailed
splicing splicing the six stranded conductors of the fairing's wiring
harness to six stranded conductors on my motorcycle. I used wire nuts.
I've ridden more than 100,000 miles since then and never parked
indoors, and those connections have never needed attention.

Pruning shrubs five years ago, I snipped the cord of my expensive
headphones. The copper strands were too fine to solder, so I taped the
three conductors with masking tape and used a wire nut to apply pressure
and provide mechanical strength. Those phones still work fine.

There are wire nuts and wing nuts and various designs in between.
The important feature is the design of the spring. The wire nut
had a round wire spring more suitable for stranded wire and the
wing nut had a square wire spring wound with the edges out so it
would cut into solid conductors making a better connection. The
designs have morphed over the years with manufactures claiming
suitability for both stranded and solid wires. I always look in
the cavity of the connector before using it to see how it's made
and/or if the darn spring is even there or corroded. Some of the
wire/wing nuts have expansion room inside for the spring to expand
which can make a better connection. I've grown fond of the newer
push in connectors which I've had very good luck with.

http://tinyurl.com/nw5nt3

TDD

Andrew M. Saucci, Jr. wrote:
In my experience, electrical tape loses its stickiness long before
any other component in an electrical installation would otherwise fail or
need to be replaced. I don't have lots of faith in electrical tape for any
long-term role of importance and try to avoid using it for anything other
than holding a cable onto a snake.


It depends on the quality of the electrical tape. I can look at
a connection done with 3M 33+ tape and it will be just as good
as it was years before. We used to use the 3M tape for permanent
connections and cheap Jap wrap, now Chink wrap for wire pulling.

TDD

David Nebenzahl wrote:
On 8/19/2009 10:41 PM The Daring Dufas spake thus:

I've grown fond of the newer push in connectors which I've had very
good luck with.

http://tinyurl.com/nw5nt3

(or the real URL,
http://www.idealindustries.com/prodD...prodId=in-sure)

Interesting. One thing, though: it looks as if there's no way to pull
the wire out once it's in. Is that the case? If so, then these may be
great connectors to use when one is sure that one's work will never need
to be redone.



If you twist and pull at the same time you can pull the
wire out but it will not come loose on its own. It does
not seem to affect reuseability.

TDD

bud-- wrote:

Pete C. wrote:
bud-- wrote:
Pete C. wrote:
bud-- wrote:
Larry The Snake Guy wrote:
On Aug 14, 2:51 pm, David Nebenzahl wrote:

First of all, it is an approved, UL/CSA tested, and, most importantly,
code-approved (US building code) wiring method. If it was as all-fired
bad as folks here claim, why would it still be allowed? After all, the
building codes tend to err on the side of caution.
However, all kinds of unreliable crap is UL listed. A UL listing is a
pretty good indication that something probably won't kill you or burn
down your house, but says nothing at all about whether it will
function properly.

By coincidence I have the UL standard [15 years old] for "Snap Switches".
For AC-only switches (which is what are commonly used) the switch must
pass all the following at rated voltage:
- 10,000 operations at rated current
- 10,000 operations at rated current and power factor around 0.8
- 10,000 operations at rated current controlling incandescent loads
[high inrush current]
- 100 operations at 4.8x rated current and power factor around 0.5

IMHO this is testing for whether the switch will "function properly".

My recollection is receptacle tests are similarly rigorous and include
plugging and unplugging and operating for a periods at significantly
above rated current.

I think most of us would be very unhappy if fuses or circuit breakers
that are UL listed did not "function properly".

For devices like TVs, it is not possible (or desirable) for UL to
determine if the device is actually useful. The test is whether the
device will "kill you or burn down your house".

Standards may not be perfect. They weren't for #12 backstabs, old
technology #12 and #10 aluminum wire, or devices originally used with
that wire. And standards for GFCIs have changed quite a bit.

IMHO standards are not adequate for #14 backstabs - maybe if they were
limited to #20 wire or smaller....

Building codes put a little more emphasis on
function, but are also updated fairly regularly because things that
were once required are finally proven to be bad ideas.
The NEC has very few equipment construction requirements and I can't
think of any performance requirements.

The 'prime directive' is that "equipment required or permitted by this
Code shall be acceptable only if approved".

"Approved" is "acceptable to the authority having jurisdiction."

The NEC generally has only a few rather general guidelines on what
should be acceptable. "Authorities" generally accept equipment that is
"listed" or "labeled", but it is up to the "authorities".

The NEC did not eliminate #12 backstabs or change requirements for #12
and #10 aluminum wiring.

--
bud--
The standard you quote may or may not test whether the device will
"function properly" as you did not include the pass / fail standards. If
the fail standard is "fire" and the pass standard is "no fire", then the
switch could well stop functioning "properly" well under the cycle count
limit and still pass the test.
The "pass standard", _as I stated_, is that "the switch must pass all
the following". The switch must still work after over 30,000 operations.
And that is only part of the standard.

What you stated, did not include pass criteria as *I stated*.

My original post said "the switch must pass all the following at rated
voltage". I quoted a portion of that in my last post. With minimal
reading ability anyone should be able to determine the UL test requires
a switch to survive over 30,000 operations at rated voltage and at least
rated current.

Again, that is incomplete criteria as it does not clearly specify the
pass / fail criteria. It is entirely possible for a device to be cycled
that many times, with the rated voltage and current applied and fail in
a way that presents no fire or shock hazard. and pass a safety test.



UL standards, as they apply to wiring components (switches, receptacles,
fuses, circuit breakers, panels, wire, motor starters, wire nuts, ...),
is that those products will "function properly", not just that they will
fail safely.

You say that, but you did not post the actual UL test pass criteria.

With minimal reading ability anyone should be able to determine switches
need to pass all of the following:

- 10,000 operations at rated current
- 10,000 operations at rated current and power factor around 0.8
- 10,000 operations at rated current controlling incandescent loads
[high inrush current]
- 100 operations at 4.8x rated current and power factor around 0.5

That is what my original post said and the requirements were taken from
the UL standard.

And again, anyone with minimal reading ability can see that what you
quoted is not a complete test specification and does not include the
pass / fail criteria.



For some other equipment, like TVs and industrial control panels, it is
not practical or desirable to test if the device functions as intended,
and the test is that it fails safely. That may involve using "listed" or
"recognized" component parts that are tested to "function properly" as
above.

All UL tests that I'm aware of test only for safety, not durability,
reliability, or functionality. If the device does not cause a hazardous
condition that might result in an insurance claim (note it is
*Underwriters* Laboratories, not *Consumers* Laboratories), it passes.

Then you are apparently not aware of a lot of UL tests.

I've seen a number of them and none had anything to do with non safety
durability. A product could be a piece of crap and fail, as long as the
failure mode did not create a hazard that could lead to an insurance
claim.

Pete C. wrote:
bud-- wrote:
Pete C. wrote:
bud-- wrote:
Pete C. wrote:
bud-- wrote:
Larry The Snake Guy wrote:
On Aug 14, 2:51 pm, David Nebenzahl wrote:

First of all, it is an approved, UL/CSA tested, and, most importantly,
code-approved (US building code) wiring method. If it was as all-fired
bad as folks here claim, why would it still be allowed? After all, the
building codes tend to err on the side of caution.
However, all kinds of unreliable crap is UL listed. A UL listing is a
pretty good indication that something probably won't kill you or burn
down your house, but says nothing at all about whether it will
function properly.

By coincidence I have the UL standard [15 years old] for "Snap Switches".
For AC-only switches (which is what are commonly used) the switch must
pass all the following at rated voltage:
- 10,000 operations at rated current
- 10,000 operations at rated current and power factor around 0.8
- 10,000 operations at rated current controlling incandescent loads
[high inrush current]
- 100 operations at 4.8x rated current and power factor around 0.5

IMHO this is testing for whether the switch will "function properly".

My recollection is receptacle tests are similarly rigorous and include
plugging and unplugging and operating for a periods at significantly
above rated current.

I think most of us would be very unhappy if fuses or circuit breakers
that are UL listed did not "function properly".

For devices like TVs, it is not possible (or desirable) for UL to
determine if the device is actually useful. The test is whether the
device will "kill you or burn down your house".

Standards may not be perfect. They weren't for #12 backstabs, old
technology #12 and #10 aluminum wire, or devices originally used with
that wire. And standards for GFCIs have changed quite a bit.

IMHO standards are not adequate for #14 backstabs - maybe if they were
limited to #20 wire or smaller....

Building codes put a little more emphasis on
function, but are also updated fairly regularly because things that
were once required are finally proven to be bad ideas.
The NEC has very few equipment construction requirements and I can't
think of any performance requirements.

The 'prime directive' is that "equipment required or permitted by this
Code shall be acceptable only if approved".

"Approved" is "acceptable to the authority having jurisdiction."

The NEC generally has only a few rather general guidelines on what
should be acceptable. "Authorities" generally accept equipment that is
"listed" or "labeled", but it is up to the "authorities".

The NEC did not eliminate #12 backstabs or change requirements for #12
and #10 aluminum wiring.

--
bud--
The standard you quote may or may not test whether the device will
"function properly" as you did not include the pass / fail standards. If
the fail standard is "fire" and the pass standard is "no fire", then the
switch could well stop functioning "properly" well under the cycle count
limit and still pass the test.
The "pass standard", _as I stated_, is that "the switch must pass all
the following". The switch must still work after over 30,000 operations.
And that is only part of the standard.
What you stated, did not include pass criteria as *I stated*.
My original post said "the switch must pass all the following at rated
voltage". I quoted a portion of that in my last post. With minimal
reading ability anyone should be able to determine the UL test requires
a switch to survive over 30,000 operations at rated voltage and at least
rated current.

Again, that is incomplete criteria as it does not clearly specify the
pass / fail criteria. It is entirely possible for a device to be cycled
that many times, with the rated voltage and current applied and fail in
a way that presents no fire or shock hazard. and pass a safety test.

The pass criteria, as I have said several times, is the switch survives
over 30,000 specified operations at rated voltage and at least rated
current and is functional at the end of the tests. The switch is not
allowed to fail during the 30,000 tests. A switch must "function
properly" to survive over 30,000 operations.

UL standards, as they apply to wiring components (switches, receptacles,
fuses, circuit breakers, panels, wire, motor starters, wire nuts, ...),
is that those products will "function properly", not just that they will
fail safely.
You say that, but you did not post the actual UL test pass criteria.
With minimal reading ability anyone should be able to determine switches
need to pass all of the following:

- 10,000 operations at rated current
- 10,000 operations at rated current and power factor around 0.8
- 10,000 operations at rated current controlling incandescent loads
[high inrush current]
- 100 operations at 4.8x rated current and power factor around 0.5

That is what my original post said and the requirements were taken from
the UL standard.

And again, anyone with minimal reading ability can see that what you
quoted is not a complete test specification

What more do you want? From the information given I could construct
tests for the 30,000 operations. You want the exact language from UL?
Maybe you could look at your copy of UL30. The switch is not allowed to
fail during the 30,000 tests. There are other additional specs, but a
switch must "function properly" to survive over 30,000 operations. The
test is not just about "failing safely".

and does not include the
pass / fail criteria.

THE PASS CRITERIA, AS I HAVE SAID SEVERAL TIMES ALREADY, IS THE SWITCH
SURVIVES OVER 30,000 SPECIFIED OPERATIONS AT RATED VOLTAGE AND AT LEAST
RATED CURRENT AND IS FUNCTIONAL AT THE END OF THE TESTS.

Did it come through that time?

For some other equipment, like TVs and industrial control panels, it is
not practical or desirable to test if the device functions as intended,
and the test is that it fails safely. That may involve using "listed" or
"recognized" component parts that are tested to "function properly" as
above.
All UL tests that I'm aware of test only for safety, not durability,
reliability, or functionality. If the device does not cause a hazardous
condition that might result in an insurance claim (note it is
*Underwriters* Laboratories, not *Consumers* Laboratories), it passes.
Then you are apparently not aware of a lot of UL tests.

I've seen a number of them and none had anything to do with non safety
durability. A product could be a piece of crap and fail, as long as the
failure mode did not create a hazard that could lead to an insurance
claim.

As have said several times, a switch must survive all 30,000 specified
operations and be functional at the end to be UL listed. A piece of crap
is not likely to survive 30,000 operations and remain functional.

Or do you think a piece of crap can survive 30,000 operations and remain
functional?

What UL standards have you read?

Do you really think the electrical industry would allow, for example,
fuses and circuit breakers to open at random current levels, and only be
required to "fail safely"? That would be ridiculous. I have not read the
standard but I have seen references to required clearing times at 120%
and 200% of rated current rating. They certainly are tested at their
rated available fault current. I expect a lot more from fuses and
circuit breakers than that they just "fail safely".

--
bud--

bud-- wrote:

Pete C. wrote:
bud-- wrote:
Pete C. wrote:
bud-- wrote:
Pete C. wrote:
bud-- wrote:
Larry The Snake Guy wrote:
On Aug 14, 2:51 pm, David Nebenzahl wrote:

First of all, it is an approved, UL/CSA tested, and, most importantly,
code-approved (US building code) wiring method. If it was as all-fired
bad as folks here claim, why would it still be allowed? After all, the
building codes tend to err on the side of caution.
However, all kinds of unreliable crap is UL listed. A UL listing is a
pretty good indication that something probably won't kill you or burn
down your house, but says nothing at all about whether it will
function properly.

By coincidence I have the UL standard [15 years old] for "Snap Switches".
For AC-only switches (which is what are commonly used) the switch must
pass all the following at rated voltage:
- 10,000 operations at rated current
- 10,000 operations at rated current and power factor around 0.8
- 10,000 operations at rated current controlling incandescent loads
[high inrush current]
- 100 operations at 4.8x rated current and power factor around 0.5

IMHO this is testing for whether the switch will "function properly".

My recollection is receptacle tests are similarly rigorous and include
plugging and unplugging and operating for a periods at significantly
above rated current.

I think most of us would be very unhappy if fuses or circuit breakers
that are UL listed did not "function properly".

For devices like TVs, it is not possible (or desirable) for UL to
determine if the device is actually useful. The test is whether the
device will "kill you or burn down your house".

Standards may not be perfect. They weren't for #12 backstabs, old
technology #12 and #10 aluminum wire, or devices originally used with
that wire. And standards for GFCIs have changed quite a bit.

IMHO standards are not adequate for #14 backstabs - maybe if they were
limited to #20 wire or smaller....

Building codes put a little more emphasis on
function, but are also updated fairly regularly because things that
were once required are finally proven to be bad ideas.
The NEC has very few equipment construction requirements and I can't
think of any performance requirements.

The 'prime directive' is that "equipment required or permitted by this
Code shall be acceptable only if approved".

"Approved" is "acceptable to the authority having jurisdiction."

The NEC generally has only a few rather general guidelines on what
should be acceptable. "Authorities" generally accept equipment that is
"listed" or "labeled", but it is up to the "authorities".

The NEC did not eliminate #12 backstabs or change requirements for #12
and #10 aluminum wiring.

--
bud--
The standard you quote may or may not test whether the device will
"function properly" as you did not include the pass / fail standards. If
the fail standard is "fire" and the pass standard is "no fire", then the
switch could well stop functioning "properly" well under the cycle count
limit and still pass the test.
The "pass standard", _as I stated_, is that "the switch must pass all
the following". The switch must still work after over 30,000 operations.
And that is only part of the standard.
What you stated, did not include pass criteria as *I stated*.
My original post said "the switch must pass all the following at rated
voltage". I quoted a portion of that in my last post. With minimal
reading ability anyone should be able to determine the UL test requires
a switch to survive over 30,000 operations at rated voltage and at least
rated current.

Again, that is incomplete criteria as it does not clearly specify the
pass / fail criteria. It is entirely possible for a device to be cycled
that many times, with the rated voltage and current applied and fail in
a way that presents no fire or shock hazard. and pass a safety test.

The pass criteria, as I have said several times, is the switch survives
over 30,000 specified operations at rated voltage and at least rated
current and is functional at the end of the tests. The switch is not
allowed to fail during the 30,000 tests. A switch must "function
properly" to survive over 30,000 operations.

UL standards, as they apply to wiring components (switches, receptacles,
fuses, circuit breakers, panels, wire, motor starters, wire nuts, ...),
is that those products will "function properly", not just that they will
fail safely.
You say that, but you did not post the actual UL test pass criteria.
With minimal reading ability anyone should be able to determine switches
need to pass all of the following:

- 10,000 operations at rated current
- 10,000 operations at rated current and power factor around 0.8
- 10,000 operations at rated current controlling incandescent loads
[high inrush current]
- 100 operations at 4.8x rated current and power factor around 0.5

That is what my original post said and the requirements were taken from
the UL standard.

And again, anyone with minimal reading ability can see that what you
quoted is not a complete test specification

What more do you want? From the information given I could construct
tests for the 30,000 operations. You want the exact language from UL?
Maybe you could look at your copy of UL30. The switch is not allowed to
fail during the 30,000 tests. There are other additional specs, but a
switch must "function properly" to survive over 30,000 operations. The
test is not just about "failing safely".

and does not include the
pass / fail criteria.

THE PASS CRITERIA, AS I HAVE SAID SEVERAL TIMES ALREADY, IS THE SWITCH
SURVIVES OVER 30,000 SPECIFIED OPERATIONS AT RATED VOLTAGE AND AT LEAST
RATED CURRENT AND IS FUNCTIONAL AT THE END OF THE TESTS.

Did it come through that time?

For some other equipment, like TVs and industrial control panels, it is
not practical or desirable to test if the device functions as intended,
and the test is that it fails safely. That may involve using "listed" or
"recognized" component parts that are tested to "function properly" as
above.
All UL tests that I'm aware of test only for safety, not durability,
reliability, or functionality. If the device does not cause a hazardous
condition that might result in an insurance claim (note it is
*Underwriters* Laboratories, not *Consumers* Laboratories), it passes.
Then you are apparently not aware of a lot of UL tests.

I've seen a number of them and none had anything to do with non safety
durability. A product could be a piece of crap and fail, as long as the
failure mode did not create a hazard that could lead to an insurance
claim.

As have said several times, a switch must survive all 30,000 specified
operations and be functional at the end to be UL listed. A piece of crap
is not likely to survive 30,000 operations and remain functional.

Or do you think a piece of crap can survive 30,000 operations and remain
functional?

What UL standards have you read?

Do you really think the electrical industry would allow, for example,
fuses and circuit breakers to open at random current levels, and only be
required to "fail safely"? That would be ridiculous. I have not read the
standard but I have seen references to required clearing times at 120%
and 200% of rated current rating. They certainly are tested at their
rated available fault current. I expect a lot more from fuses and
circuit breakers than that they just "fail safely".

--
bud--

You really have a reading comprehension issue. Again, what you have
quotes is not a complete test specification as would be used by any
reputable testing laboratory as it does not contain clearly defined pass
/ fail criteria.

Your diversion into circuit breakers doesn't help your case at all since
a circuit breakers are allowed to "soft fail" and trip at lower than
their rated current.

Pete C. wrote:
bud-- wrote:
Pete C. wrote:
bud-- wrote:
Pete C. wrote:
bud-- wrote:
Pete C. wrote:
bud-- wrote:
Larry The Snake Guy wrote:
On Aug 14, 2:51 pm, David Nebenzahl wrote:

First of all, it is an approved, UL/CSA tested, and, most importantly,
code-approved (US building code) wiring method. If it was as all-fired
bad as folks here claim, why would it still be allowed? After all, the
building codes tend to err on the side of caution.
However, all kinds of unreliable crap is UL listed. A UL listing is a
pretty good indication that something probably won't kill you or burn
down your house, but says nothing at all about whether it will
function properly.

By coincidence I have the UL standard [15 years old] for "Snap Switches".
For AC-only switches (which is what are commonly used) the switch must
pass all the following at rated voltage:
- 10,000 operations at rated current
- 10,000 operations at rated current and power factor around 0.8
- 10,000 operations at rated current controlling incandescent loads
[high inrush current]
- 100 operations at 4.8x rated current and power factor around 0.5

IMHO this is testing for whether the switch will "function properly".

My recollection is receptacle tests are similarly rigorous and include
plugging and unplugging and operating for a periods at significantly
above rated current.

I think most of us would be very unhappy if fuses or circuit breakers
that are UL listed did not "function properly".

For devices like TVs, it is not possible (or desirable) for UL to
determine if the device is actually useful. The test is whether the
device will "kill you or burn down your house".

Standards may not be perfect. They weren't for #12 backstabs, old
technology #12 and #10 aluminum wire, or devices originally used with
that wire. And standards for GFCIs have changed quite a bit.

IMHO standards are not adequate for #14 backstabs - maybe if they were
limited to #20 wire or smaller....

Building codes put a little more emphasis on
function, but are also updated fairly regularly because things that
were once required are finally proven to be bad ideas.
The NEC has very few equipment construction requirements and I can't
think of any performance requirements.

The 'prime directive' is that "equipment required or permitted by this
Code shall be acceptable only if approved".

"Approved" is "acceptable to the authority having jurisdiction."

The NEC generally has only a few rather general guidelines on what
should be acceptable. "Authorities" generally accept equipment that is
"listed" or "labeled", but it is up to the "authorities".

The NEC did not eliminate #12 backstabs or change requirements for #12
and #10 aluminum wiring.

--
bud--
The standard you quote may or may not test whether the device will
"function properly" as you did not include the pass / fail standards. If
the fail standard is "fire" and the pass standard is "no fire", then the
switch could well stop functioning "properly" well under the cycle count
limit and still pass the test.
The "pass standard", _as I stated_, is that "the switch must pass all
the following". The switch must still work after over 30,000 operations.
And that is only part of the standard.
What you stated, did not include pass criteria as *I stated*.
My original post said "the switch must pass all the following at rated
voltage". I quoted a portion of that in my last post. With minimal
reading ability anyone should be able to determine the UL test requires
a switch to survive over 30,000 operations at rated voltage and at least
rated current.
Again, that is incomplete criteria as it does not clearly specify the
pass / fail criteria. It is entirely possible for a device to be cycled
that many times, with the rated voltage and current applied and fail in
a way that presents no fire or shock hazard. and pass a safety test.
The pass criteria, as I have said several times, is the switch survives
over 30,000 specified operations at rated voltage and at least rated
current and is functional at the end of the tests. The switch is not
allowed to fail during the 30,000 tests. A switch must "function
properly" to survive over 30,000 operations.

UL standards, as they apply to wiring components (switches, receptacles,
fuses, circuit breakers, panels, wire, motor starters, wire nuts, ...),
is that those products will "function properly", not just that they will
fail safely.
You say that, but you did not post the actual UL test pass criteria.
With minimal reading ability anyone should be able to determine switches
need to pass all of the following:

- 10,000 operations at rated current
- 10,000 operations at rated current and power factor around 0.8
- 10,000 operations at rated current controlling incandescent loads
[high inrush current]
- 100 operations at 4.8x rated current and power factor around 0.5

That is what my original post said and the requirements were taken from
the UL standard.
And again, anyone with minimal reading ability can see that what you
quoted is not a complete test specification
What more do you want? From the information given I could construct
tests for the 30,000 operations. You want the exact language from UL?
Maybe you could look at your copy of UL30. The switch is not allowed to
fail during the 30,000 tests. There are other additional specs, but a
switch must "function properly" to survive over 30,000 operations. The
test is not just about "failing safely".

and does not include the
pass / fail criteria.
THE PASS CRITERIA, AS I HAVE SAID SEVERAL TIMES ALREADY, IS THE SWITCH
SURVIVES OVER 30,000 SPECIFIED OPERATIONS AT RATED VOLTAGE AND AT LEAST
RATED CURRENT AND IS FUNCTIONAL AT THE END OF THE TESTS.

Did it come through that time?

For some other equipment, like TVs and industrial control panels, it is
not practical or desirable to test if the device functions as intended,
and the test is that it fails safely. That may involve using "listed" or
"recognized" component parts that are tested to "function properly" as
above.
All UL tests that I'm aware of test only for safety, not durability,
reliability, or functionality. If the device does not cause a hazardous
condition that might result in an insurance claim (note it is
*Underwriters* Laboratories, not *Consumers* Laboratories), it passes.
Then you are apparently not aware of a lot of UL tests.
I've seen a number of them and none had anything to do with non safety
durability. A product could be a piece of crap and fail, as long as the
failure mode did not create a hazard that could lead to an insurance
claim.
As have said several times, a switch must survive all 30,000 specified
operations and be functional at the end to be UL listed. A piece of crap
is not likely to survive 30,000 operations and remain functional.

Or do you think a piece of crap can survive 30,000 operations and remain
functional?

What UL standards have you read?

Do you really think the electrical industry would allow, for example,
fuses and circuit breakers to open at random current levels, and only be
required to "fail safely"? That would be ridiculous. I have not read the
standard but I have seen references to required clearing times at 120%
and 200% of rated current rating. They certainly are tested at their
rated available fault current. I expect a lot more from fuses and
circuit breakers than that they just "fail safely".


You really have a reading comprehension issue. Again, what you have
quotes is not a complete test specification as would be used by any
reputable testing laboratory as it does not contain clearly defined pass
/ fail criteria.

You have not explained how surviving 30,000 specified operations and
remaining functional is not a pass criteria.


Your diversion into circuit breakers doesn't help your case at all since
a circuit breakers are allowed to "soft fail" and trip at lower than
their rated current.

Every manufacturer current-time trip curve shows an acceptable band. I
have no doubt UL specifies a similar band (ie max and min acceptable
clearing time at 200% of rated current). Tripping at too low a current
is also not permitted. You really think the electrical industry would
allow fuses/breakers to open at too low a current?

What UL standards have you read?

--
bud--

On 8/21/2009 6:14 AM Pete C. spake thus:

You really have a reading comprehension issue. Again, what you have
quotes is not a complete test specification as would be used by any
reputable testing laboratory as it does not contain clearly defined pass
/ fail criteria.

Your diversion into circuit breakers doesn't help your case at all since
a circuit breakers are allowed to "soft fail" and trip at lower than
their rated current.

I've watched this argument devolve here for a while now. Although I
don't know what exactly UL uses for their test criteria, I find it very
hard to believe that they would approve devices that only "fail safely"
but that do not function properly at that point of failure (i.e.,
breakers that trip at significantly lower current than rated, switches
that no longer switch, etc.).

I think the burden of proof in this case is on *you*.


--
Found--the gene that causes belief in genetic determinism

David Nebenzahl wrote:

On 8/21/2009 6:14 AM Pete C. spake thus:

You really have a reading comprehension issue. Again, what you have
quotes is not a complete test specification as would be used by any
reputable testing laboratory as it does not contain clearly defined pass
/ fail criteria.

Your diversion into circuit breakers doesn't help your case at all since
a circuit breakers are allowed to "soft fail" and trip at lower than
their rated current.

I've watched this argument devolve here for a while now. Although I
don't know what exactly UL uses for their test criteria, I find it very
hard to believe that they would approve devices that only "fail safely"
but that do not function properly at that point of failure (i.e.,
breakers that trip at significantly lower current than rated, switches
that no longer switch, etc.).

I think the burden of proof in this case is on *you*.

The burden of proof is on the person falsely claiming to be posting a UL
test standard. No reputable testing laboratory would attempt to test to
an incomplete test specification such as what mr bud has posted.

Remember was chartered to do product testing for the insurance industry,
not consumers. Insurers do not care at all about the quality,
functionality or value of a product, only if the product presents a
safety hazard that could lead to an insurance claim.

Circuit breakers are designed to and allowed to trip at a lower point as
they wear from multiple trips or age. They are not allowed to trip at a
higher than specified level. A "weak" breaker is a common failure and
does not present any safety hazard so it is not of any concert to
insurance underwriters nor to their testing lab.

Pete C. wrote:
David Nebenzahl wrote:
On 8/21/2009 6:14 AM Pete C. spake thus:

You really have a reading comprehension issue. Again, what you have
quotes is not a complete test specification as would be used by any
reputable testing laboratory as it does not contain clearly defined pass
/ fail criteria.

Your diversion into circuit breakers doesn't help your case at all since
a circuit breakers are allowed to "soft fail" and trip at lower than
their rated current.
I've watched this argument devolve here for a while now. Although I
don't know what exactly UL uses for their test criteria, I find it very
hard to believe that they would approve devices that only "fail safely"
but that do not function properly at that point of failure (i.e.,
breakers that trip at significantly lower current than rated, switches
that no longer switch, etc.).

I think the burden of proof in this case is on *you*.

The burden of proof is on the person falsely claiming to be posting a UL
test standard. No reputable testing laboratory would attempt to test to
an incomplete test specification such as what mr bud has posted.

Apparently Pete wants all 35 pages of UL20.

My original point was that, contrary to what had been stated, UL tests
for some products do establish whether a device will "function
properly". IMHO remaining functional after over 30,000 operations at or
above rated voltage and current demonstrates that.

I would have no trouble designing tests for the 30,100 operations which
I took from UL20. I would also have no problem determining if a switch
passed those tests. (The standard has additional details on these tests
and additional requirements.)

Pete has not said why he couldn't figure out the tests or whether a
switch passed.
(But that was not my intent anyway. I don't care if Pete can't figure
out how to make the tests.)
Pete is welcome to look at his copy and say what UL20 requires. I
eagerly wait.

Remember was chartered to do product testing for the insurance industry,
not consumers. Insurers do not care at all about the quality,
functionality or value of a product, only if the product presents a
safety hazard that could lead to an insurance claim.

The foregone conclusion results in denying the evidence?

Whatever the origin of UL it is, frankly, laughable to think that the
electrical industry would allow the present UL to list products used in
the electric power industry that have not been tested to "function
properly". Like for instance fuses, circuit breakers, motor starters,
switches, receptacles, GFCIs, AFCIs, ....

From the UL "white book":
"UL and its subsidiaries operate facilities throughout the world for the
testing, certification and quality assessment of products, systems and
services."
Note "quality assessment".

Take a particular category, fuses. A fuse could itself fail safely (or
operate but out of time spec) and still allow great damage, including
fire and explosion, downstream. It could also be the difference between
an electrician walking away from an event and severe injury or death
from arc flash. (I believe even insurers might be interested in that.)

Circuit breakers are designed to and allowed to trip at a lower point as
they wear from multiple trips or age. They are not allowed to trip at a
higher than specified level. A "weak" breaker is a common failure and
does not present any safety hazard so it is not of any concert to
insurance underwriters nor to their testing lab.

Cite.

Still missing - the UL standards you have read that had nothing "to do
with non safety durability".

Also missing - the "proof" David asked for.
My source is UL20.

--
bud--

If you twist and pull at the same time you can pull the
wire out but it will not come loose on its own. It does
not seem to affect reuseability.

Some/most of them have a "slot" that will accept a very small flat blade
screwdriver. Push in the screwdrive and they release the wire.

Apparently the industry has solved the safety and reliability with the
"backstabing" outlets. Also there are connectors that use the same
"technology." They make them in a variety of "sizes" for wires sizes and
the number of conductors to be joined. They are "UL" approved so I guess
they are 'gud enuf.' I used the connectors in my attic and so far the
house hasn't burned down. But even the manufacturer says that they have
more resistance than your typical twisting wirenut connection. I guess,
however, it's within the range of acceptability.

BTW: "They" have finally made an "approved" splice for romex so that you
don't have to use a junction box when you can't "stretch" a cable when you
move a ceiling outlet or whatever. I pick up one on speculation but
haven't used it.

John Gilmer wrote:
If you twist and pull at the same time you can pull the
wire out but it will not come loose on its own. It does
not seem to affect reuseability.

Some/most of them have a "slot" that will accept a very small flat blade
screwdriver. Push in the screwdrive and they release the wire.

Apparently the industry has solved the safety and reliability with the
"backstabing" outlets. Also there are connectors that use the same
"technology." They make them in a variety of "sizes" for wires sizes and
the number of conductors to be joined. They are "UL" approved so I guess
they are 'gud enuf.' I used the connectors in my attic and so far the
house hasn't burned down. But even the manufacturer says that they have
more resistance than your typical twisting wirenut connection. I guess,
however, it's within the range of acceptability.

BTW: "They" have finally made an "approved" splice for romex so that you
don't have to use a junction box when you can't "stretch" a cable when you
move a ceiling outlet or whatever. I pick up one on speculation but
haven't used it.



BZZZIT, wrong item, you're describing the outlets, I was describing
the Ideal brand connectors. I have some other connectors that have
a little lever you flip up to insert/release each wire.

http://www.wago.us/2631.htm

TDD

On Sun, 23 Aug 2009 20:39:09 -0400, "John Gilmer"
wrote:


If you twist and pull at the same time you can pull the
wire out but it will not come loose on its own. It does
not seem to affect reuseability.

Some/most of them have a "slot" that will accept a very small flat blade
screwdriver. Push in the screwdrive and they release the wire.

Apparently the industry has solved the safety and reliability with the
"backstabing" outlets. Also there are connectors that use the same
"technology." They make them in a variety of "sizes" for wires sizes and
the number of conductors to be joined. They are "UL" approved so I guess
they are 'gud enuf.' I used the connectors in my attic and so far the
house hasn't burned down. But even the manufacturer says that they have
more resistance than your typical twisting wirenut connection. I guess,
however, it's within the range of acceptability.

BTW: "They" have finally made an "approved" splice for romex so that you
don't have to use a junction box when you can't "stretch" a cable when you
move a ceiling outlet or whatever. I pick up one on speculation but
haven't used it.

It's approved today - but don't count on it being approved 5 years
from now. It was developed for the "mobile home" market - and that's
where it belongs (10 year lifespan, perhaps?)

The Daring Dufas wrote in
:

E Z Peaces wrote:
Robert Green wrote:

Newbies and wire nuts don't mix well, either. Stripped end of
wires too long, too short, wrong size nut, wrong mix of wires,
twist not twisted enough. There's no end to sad tales with wire
nuts in the hands of the inexperienced. My favorite is three wires
under one nut with a virtually untwisted center wire that pulls
right out on the first tug. I am much more
concerned with bad wire nutting than with backstabbing.

--
Bobby G.


The connection would probably have been strong if all three wires had
been virtually untwisted. When John Blomstrand filed to patent the
wire nut in 1950, that was his intent. If wires are straight and
solid and of equal gage with even ends, I suppose the threads of a
wire nut should engage every wire in a bundle of as many as six,
mashing them together with no wiggle room.

Thirty years ago it was apparently common for electricians to use
wire nuts badly, twisting wires together clockwise before twisting on
the connector clockwise, then hoping tape would hold everything in
place. I've redone many.

I love wire nuts even for conductors of dissimilar gages and stranded
conductors, each of which may make it trickier to use wire nuts.
Nearly 40 years ago, I installed a fairing on my motorcycle, which
entailed splicing splicing the six stranded conductors of the
fairing's wiring harness to six stranded conductors on my motorcycle.
I used wire nuts.
I've ridden more than 100,000 miles since then and never parked
indoors, and those connections have never needed attention.

Pruning shrubs five years ago, I snipped the cord of my expensive
headphones. The copper strands were too fine to solder, so I taped
the three conductors with masking tape and used a wire nut to apply
pressure and provide mechanical strength. Those phones still work
fine.

There are wire nuts and wing nuts and various designs in between.
The important feature is the design of the spring. The wire nut
had a round wire spring more suitable for stranded wire and the
wing nut had a square wire spring wound with the edges out so it
would cut into solid conductors making a better connection. The
designs have morphed over the years with manufactures claiming
suitability for both stranded and solid wires. I always look in
the cavity of the connector before using it to see how it's made
and/or if the darn spring is even there or corroded. Some of the
wire/wing nuts have expansion room inside for the spring to expand
which can make a better connection. I've grown fond of the newer
push in connectors which I've had very good luck with.

http://tinyurl.com/nw5nt3

TDD


Those are interesting. Never used them for 12/14 wire. Have seen on light
duty apps.