On Sun, 01 Jul 2007 08:43:15 -0700, Don Bowey
wrote:

On 7/1/07 7:37 AM, in article ,
"John Fields" wrote:

On Fri, 29 Jun 2007 00:50:22 GMT, Eeyore
wrote:



John Fields wrote:

Eeyorewrote:
" wrote:

Well, much of the "fires" due to faulty wiring are because we have
*had* wiring as a general condition in most houses since the early
1900s, so after 100 years or so it gets a little tired, and when
overloaded can fail. Of course, 100 years ago, y'all had very nice
green lawns and gorgeous buildings.... but little electricity other
than the very wealthy.

I'd like to see some supporting data for that litle outburst.

---
It's not up to him to provide supporting data. If you want to
refute it, get off your fat, pompous ass and provide evidence to the
contrary.

Go **** a pig.

What's your mother got to do with it?


Good one John, but what took you so long?

---
Dunno... Just kind of lost track of the thread, I guess.


--
JF

On Sun, 01 Jul 2007 06:03:21 GMT, "James Sweet"
wrote:


"John Larkin" wrote in message
.. .
On Sat, 30 Jun 2007 13:35:18 -0500, Wolfi
wrote:



The lack of appropriate machanical stress handling is my biggest rejection
of
the American type 130V power plug system, in addition to extremely poor
design
of those flat contact receptacles, which wear out very easily, giving poor
contact with all bad things to follow..

Not in my experience. I've owned houses that were first wired in the
early 1900's, and I don't recall ever having a bad wall outlet. Most
of the really old ones have been replaced, not because they failed but
rather because they had to be upgraded to accept a 3-prong plug.



Boy I sure have, things got really cheap in the late 70s, about half the
outlets in my 1979 house were bad, of course they also were the cheap
bargain bin home center junk. You can get a pretty good outlet that will
last a long time for about 2 bucks, or you can get a really crappy one that
will wear out for about 75 cents. Guess which goes into most cookie cutter
houses they're building these days?


I've been in this house for about 14 years with zero electrical
problems. The British stuff is no doubt more reliable, but both are
plenty good enough; the US stuff works and is a tiny overall hazard to
life compared to other things.

John

On Sun, 01 Jul 2007 01:16:30 -0500, Wolfi
wrote:


I can't comment on that, since I don't have reliable data, but simply asked,
what about the other plain? And it also is much easier to have a slotted pipe
type receptacle, with a steel tape spring surrounding it to guarantee,
constant, long-term contact pressure for a round, mechanically sound, 5mm pin,
which gives solid, equal contact all around its circumference.

I think it has a good reason that the later added third ground pin for the US
system isn't of flat spade shape anymore, but strangely a round one now with,
who would have thought it, 5mm like in the Schuko system as well ;-)

All three pins on the other end of an IEC power cord are flat blades.

John

On Thu, 28 Jun 2007 18:34:19 +0100, "Dave Plowman (News)"
wrote:

In article .com,
wrote:
Well, much of the "fires" due to faulty wiring are because we have
*had* wiring as a general condition in most houses since the early
1900s, so after 100 years or so it gets a little tired, and when
overloaded can fail. Of course, 100 years ago, y'all had very nice
green lawns and gorgeous buildings.... but little electricity other
than the very wealthy.

You're not saying there is 100 year old wiring still in use?

My previous house, a Victorian built in 1892, had gas pipes leading to
all the lighting fixtures, capped off, and exposed knob-and-tube
wiring in the attic. Junctions were twisted and taped, hanging in
mid-air. I assume the original wiring was intended for lighting, and
over the years, as more loads were added, it became less suited. I had
a few joints open up, and eventually rewired it with Romex, with all
joints inside proper metal junction boxes. There's still a lot of
ancient fabric-insulated, twisted-junction knob-and-tube stuff around.

http://www.oldhouseweb.com/stories/Detailed/10327.shtml

http://www.knobandtubewiring.com/knob%20and%20tube.gif

It's common to see a fuse box, designed for 5 or 10-amp screw-in
fuses, to be full of 30's.


Around here, knob-and-tube was succeded by mandatory rigid steel
conduit and later, roughly 1960 maybe, Romex. Commercial buildings
must still use conduit, rigid metal pipe or the flexible MX stuff.
There is no requirement that old construction be upgraded, unless a
major remodel is done.


John

krw wrote:
In article BNjhi.51$DM4.37@trndny06, says...
"N Cook" wrote in message
...
Rich Grise wrote in message
news On Thu, 28 Jun 2007 07:45:50 +0100, N Cook wrote:
Could someone direct me to pics of the 2 different types of plug/socket
system used in the USA to differentiate for medium and high power use,
I
didn't even realise 220 or 240V was used residentially anywhere in the
USA.
http://www.voltec-industries.com/nema_chart.html
https://www.hubbellnet.com/max_htm/t...EMA/front.html
http://nooutage.com/nema_configurations.htm

Hope This Helps!
Rich

Helps ?
It must be easier learning Japanese than learning to differentiate all
that
lot and then ominously on top of that sections marked "Reserved for Future
Configurations"
Is it subsets of that lot for each state or each utility company or a
total
mish-mash ?


There's about 3 different types of receptacles you'll find in a US
residence, the rest on that list are either industrial stuff or obsolete
things you might find in the occasional 1950s or earlier house. Generally
you'll find mostly 15A 120V grounded types, then the clothes dryer will have
a 30A 240V receptacle and the kitchen stove will have a 50A 240V receptacle.
Other high powered items like an electric furnace, water heater, spa, etc
will be hard wired. Sometimes you'll find a 15 or 20A 240V receptacle in the
garage for something like an air compressor or small arc welder but these
are generally added by the homeowner. It's really not very complicated.

There are also outlets used for room air conditioners. I have a 120V
15/20A outlet by one window downstairs and a 240V 20A (IIRC) outlet
for the thru-the-wall AC. Stoves and clothes dryers may also have
either a three pin ungrounded or four pin grounded outlet.
I know the UK has a number of plugs and receptacles in the same category,
I've got a small pile of various oddballs from over there right here.

In addition, there are at least a couple of different 240v outlets used
for clothes dryers. In fact that's one appliance commonly supplied
'minus' a cord...the appropriate one being fitted at time of installation.

jak

John Larkin wrote:
On Sat, 30 Jun 2007 14:11:02 -0500, jakdedert
wrote:

John Larkin wrote:
On Sat, 30 Jun 2007 13:35:18 -0500, Wolfi
wrote:


The lack of appropriate machanical stress handling is my biggest rejection of
the American type 130V power plug system, in addition to extremely poor design
of those flat contact receptacles, which wear out very easily, giving poor
contact with all bad things to follow..
Not in my experience. I've owned houses that were first wired in the
early 1900's, and I don't recall ever having a bad wall outlet. Most
of the really old ones have been replaced, not because they failed but
rather because they had to be upgraded to accept a 3-prong plug.

A decent 3-prong molded plug, plugged into even a cheap (79 cent) dual
wall outlet, seems to be perfectly reliable. Our biggest problem is
cats chewing on the cords, some of which seem to be tastier than
others.

John



I've replaced a number of two prong outlets in my house (vintage 1928)
because the outlets failed in just the manner described. I don't know
the actual vintage of the particular sockets involved--although it's
pertinent that no two were the same, leading me to believe that they
themselves were later replacements for the originals.

In some cases it was possible to easily rewire with grounded 12/2 romex
from the breaker box. In others, where that was not practical, the
two-prongers were replaced with new outlets--also two prong.

These are still available and should be used if upgrading to a properly
grounded outlet is not done.

In any case, IME the OP's statement is entirely accurate. The
edison-style outlets are either inherently--or at least 'as
implemented'--prone to losing secure contact.


They are about the same as the IEC connector on the other end of most
power cords. No big deal.

Physically, perhaps, but inasmuch as the IEC connector is a temporary
connection (and user replaceable), and the Edison is supposed to be
permanent...not the same at all.

I think that the number of deaths from US-style outlets is minute.
Electrocution and electrical fires result mostly from bad/old house
wiring and faulty appliances.

Electrocution rarely if ever results from a faulty connection, although
the Edison plug design is prone to tampering and accidental shock hazard
by children. It's possible to partially insert the plug and little
fingers to get on the exposed--but energized--prongs.

Germany runs about 1 PPM annual risk of death from electrocution, with
the USA closer to 2 PPM. That's not a lot of risk. I recall reading
that the majority of electrocutions in the US are on construction
sites, things like machines and ladders hitting high-voltage lines.

Perhaps you're referring back to an earlier part of the thread, but
there is nothing in this post about electrocution. Rereading the above,
it is about the propensity of the common Edison socket to wear out and
cause intermittent connections.

FIRE hazard, not electrocution.....

Really, cars are hundreds of times more dangerous than electricity,
and cigarettes 10x again. If Europeans want to save lives, they should
discourage smoking.

Those hazards are being addressed. What does the above have to do with
the shortcomings of American Edison sockets?

jak
John

On 28 Jun, 23:12, Richard The Dreaded Libertarian
wrote:
On Wed, 27 Jun 2007 19:57:19 -0700, b wrote:
On 27 jun, 22:56, "TT_Man" wrote

I've spent time in the US and Japan, and I have to say that those flat
blade sockets are an atrocious design. They suffer sloppy fit problems
very easily . Those countries don't seem to have switched wall sockets
either, which the Uk standard has, so you get more arcing if plugging
in live equipment

In the US, we know better than to do stupid crap like plugging in live
equipment.

Good Luck!
Rich

Are you really saying no-one ever unplugs things withoutout turning
them off first? I really doubt it.


NT

wrote in news:1183330881.790940.287160
@n2g2000hse.googlegroups.com:

Are you really saying no-one ever unplugs things withoutout turning
them off first? I really doubt it.


Some equipment simply has no off switch..

"Gary Tait" wrote in message
...
wrote in news:1183330881.790940.287160
@n2g2000hse.googlegroups.com:

Are you really saying no-one ever unplugs things withoutout turning
them off first? I really doubt it.


Some equipment simply has no off switch..

Who cares? I unplug and plug in items that are turned on all the time, worst
case you get a little spark, it doesn't cause any problems. It's not hot
enough to pit the plug prongs or contacts.

"John Larkin" wrote in message
...
On Sat, 30 Jun 2007 14:11:02 -0500, jakdedert
wrote:

John Larkin wrote:
On Sat, 30 Jun 2007 13:35:18 -0500, Wolfi
wrote:


The lack of appropriate machanical stress handling is my biggest
rejection of
the American type 130V power plug system, in addition to extremely poor
design
of those flat contact receptacles, which wear out very easily, giving
poor
contact with all bad things to follow..

Not in my experience. I've owned houses that were first wired in the
early 1900's, and I don't recall ever having a bad wall outlet. Most
of the really old ones have been replaced, not because they failed but
rather because they had to be upgraded to accept a 3-prong plug.

A decent 3-prong molded plug, plugged into even a cheap (79 cent) dual
wall outlet, seems to be perfectly reliable. Our biggest problem is
cats chewing on the cords, some of which seem to be tastier than
others.

John



I've replaced a number of two prong outlets in my house (vintage 1928)
because the outlets failed in just the manner described. I don't know
the actual vintage of the particular sockets involved--although it's
pertinent that no two were the same, leading me to believe that they
themselves were later replacements for the originals.

In some cases it was possible to easily rewired with grounded 12/2 romex
from the breaker box. In others, where that was not practical, the
two-prongers were replaced with new outlets--also two prong.

These are still available and should be used if upgrading to a properly
grounded outlet is not done.

In any case, IME the OP's statement is entirely accurate. The
edison-style outlets are either inherently--or at least 'as
implemented'--prone to losing secure contact.


They are about the same as the IEC connector on the other end of most
power cords. No big deal.

I think that the number of deaths from US-style outlets is minute.
Electrocution and electrical fires result mostly from bad/old house
wiring and faulty appliances.

Germany runs about 1 PPM annual risk of death from electrocution, with
the USA closer to 2 PPM. That's not a lot of risk. I recall reading
that the majority of electrocutions in the US are on construction
sites, things like machines and ladders hitting high-voltage lines.

I really can't recall reading about anybody being electrocuted inside a
house. I do recall a case involving a swimming pool. Typically, someone
manages to get across a 2.4 KV line; there one of three things that will
happens: 1 - you get bad burns and live, 2 - you fall off the ladder and die
of the fall, 3 - you die of the electrocution. Probably the worst case is
somebody holding on to an aluminum ladder with both hands that comes in
contact with an electric wire. Your chances of being electrocuted due to
casual contact with a 120 line are pretty much nil.

Tam

Really, cars are hundreds of times more dangerous than electricity,
and cigarettes 10x again. If Europeans want to save lives, they should
discourage smoking.

John

On Sun, 01 Jul 2007 16:27:54 -0500, jakdedert
wrote:

John Larkin wrote:
On Sat, 30 Jun 2007 14:11:02 -0500, jakdedert
wrote:

John Larkin wrote:
On Sat, 30 Jun 2007 13:35:18 -0500, Wolfi
wrote:


The lack of appropriate machanical stress handling is my biggest rejection of
the American type 130V power plug system, in addition to extremely poor design
of those flat contact receptacles, which wear out very easily, giving poor
contact with all bad things to follow..
Not in my experience. I've owned houses that were first wired in the
early 1900's, and I don't recall ever having a bad wall outlet. Most
of the really old ones have been replaced, not because they failed but
rather because they had to be upgraded to accept a 3-prong plug.

A decent 3-prong molded plug, plugged into even a cheap (79 cent) dual
wall outlet, seems to be perfectly reliable. Our biggest problem is
cats chewing on the cords, some of which seem to be tastier than
others.

John



I've replaced a number of two prong outlets in my house (vintage 1928)
because the outlets failed in just the manner described. I don't know
the actual vintage of the particular sockets involved--although it's
pertinent that no two were the same, leading me to believe that they
themselves were later replacements for the originals.

In some cases it was possible to easily rewire with grounded 12/2 romex
from the breaker box. In others, where that was not practical, the
two-prongers were replaced with new outlets--also two prong.

These are still available and should be used if upgrading to a properly
grounded outlet is not done.

In any case, IME the OP's statement is entirely accurate. The
edison-style outlets are either inherently--or at least 'as
implemented'--prone to losing secure contact.


They are about the same as the IEC connector on the other end of most
power cords. No big deal.

Physically, perhaps, but inasmuch as the IEC connector is a temporary
connection (and user replaceable), and the Edison is supposed to be
permanent...not the same at all.

I think that the number of deaths from US-style outlets is minute.
Electrocution and electrical fires result mostly from bad/old house
wiring and faulty appliances.

Electrocution rarely if ever results from a faulty connection, although
the Edison plug design is prone to tampering and accidental shock hazard
by children. It's possible to partially insert the plug and little
fingers to get on the exposed--but energized--prongs.

That might generate a tickle. The geometry is very unlikely to be
lethal. Chewing on cords, especially by pets, is a more serious
hazard, and 240 is a lot worse than 120 there.



Germany runs about 1 PPM annual risk of death from electrocution, with
the USA closer to 2 PPM. That's not a lot of risk. I recall reading
that the majority of electrocutions in the US are on construction
sites, things like machines and ladders hitting high-voltage lines.

Perhaps you're referring back to an earlier part of the thread, but
there is nothing in this post about electrocution. Rereading the above,
it is about the propensity of the common Edison socket to wear out and
cause intermittent connections.

FIRE hazard, not electrocution.....

Really, cars are hundreds of times more dangerous than electricity,
and cigarettes 10x again. If Europeans want to save lives, they should
discourage smoking.

Those hazards are being addressed. What does the above have to do with
the shortcomings of American Edison sockets?


I don't have access to the statistics, but I really doubt that the
American plug/socket combo is a significant source of fires.


John

["Followup-To:" header set to sci.electronics.design.]
John Larkin wrote:

If Europeans want to save lives, they should
discourage smoking.

All European countries want to, with the quite influential exception of
Germany. I seem to remember having read that Germany was the world's biggest
cigarette exporter. That and some EUR 14b annual tobacco tax income say
progress is going to be slow, but there is some.

robert

On 2 jul, 03:36, "James Sweet" wrote:

Some equipment simply has no off switch..

Who cares? I unplug and plug in items that are turned on all the time, worst
case you get a little spark, it doesn't cause any problems. It's not hot
enough to pit the plug prongs or contacts.

may not seem so at first, but this will damage the contacts and lead
to the formation of carbonised areas. And more noticeable stateside
what with the limited 'actual' contact area between the US plugs and
sockets - I would avoid plugging in or removing plugs of live
equipment for reliability reasons.

-B

On 2 Jul, 02:36, "James Sweet" wrote:
"Gary Tait" wrote in message
...
wrote in news:1183330881.790940.287160
@n2g2000hse.googlegroups.com:

Are you really saying no-one ever unplugs things withoutout turning
them off first? I really doubt it.

Some equipment simply has no off switch..

Who cares? I unplug and plug in items that are turned on all the time, worst
case you get a little spark, it doesn't cause any problems. It's not hot
enough to pit the plug prongs or contacts.

Its well known that repeated small sparks make a total mess of the
contact surface. This was one of the problems of our olf round pin
system half a century ago.


NT

On 2 Jul, 03:59, John Larkin
wrote:

lethal. Chewing on cords, especially by pets, is a more serious
hazard, and 240 is a lot worse than 120 there.

Dont think I've ever seen pet chewed cords here, maybe different
checmicals get used in the plastic or something.

120 0r 240 would kill either way.


I don't have access to the statistics, but I really doubt that the
American plug/socket combo is a significant source of fires.

John

http://ieeexplore.ieee.org/xpl/freea...rnumber=148498


NT

On Mon, 02 Jul 2007 07:26:03 -0700, wrote:

On 2 Jul, 03:59, John Larkin
wrote:

lethal. Chewing on cords, especially by pets, is a more serious
hazard, and 240 is a lot worse than 120 there.

Dont think I've ever seen pet chewed cords here, maybe different
checmicals get used in the plastic or something.

My cats love our Apple products, which have soft vinyl cords. They
won't touch my Intel-based systems. Smart cats, no?



120 0r 240 would kill either way.

240 is much more likely to kill.



I don't have access to the statistics, but I really doubt that the
American plug/socket combo is a significant source of fires.

John

http://ieeexplore.ieee.org/xpl/freea...rnumber=148498

It's not clear that the paper is relevant, and I'm not going to buy it
to find out. Having designed equipment with, likely, a few million
1-amp-and-up connections, and no meltdowns much less fires so far, I'm
skeptical. And a US electrical plug is hardly "a current-carrying
loose copper wire connection."


John

In article .com,
wrote:
Who cares? I unplug and plug in items that are turned on all the time,
worst case you get a little spark, it doesn't cause any problems. It's
not hot enough to pit the plug prongs or contacts.

Its well known that repeated small sparks make a total mess of the
contact surface. This was one of the problems of our olf round pin
system half a century ago.

You'd have to explain that. Most of the old round pin sockets were
switched - unswitched was a short lived fashion with 13 amp stuff. At
least in my experience.

The old round pin sockets were far more likely to be overloaded, though.

--
*How many roads must a man travel down before he admits he is lost? *

Dave Plowman London SW
To e-mail, change noise into sound.

bz wrote:
jakdedert wrote in news:e6yhi.8611$09.1625
@bignews8.bellsouth.net:

In some cases it was possible to easily rewired with grounded 12/2 romex
from the breaker box. In others, where that was not practical, the
two-prongers were replaced with new outlets--also two prong.

These are still available and should be used if upgrading to a properly
grounded outlet is not done.



If an earth ground is not available, a GFI outlet should be installed at
the beginning of the run and 3 prong outlets along the rest of the run.

The GFI will trip if a ground fault is present.

The outlets should be marked to indicate that a GFI is installed and that
no earth ground is present.

I believe that this is much safer than using 2 prong outlets and meets
code.



Yes it is, and I'm perfectly aware of the fact. OTOH, replacing with
original equipment is far more responsible than doing what most people
do: replacing with a three prong outlet and either leaving the ground to
float...or worse yet, bonding ground to neutral.

Eventually, all those two-blade outlets will be rewired properly, with
new circuits added. I've done about 25% of the house so far, but it's
slow going....

jak

jak

On Mon, 02 Jul 2007 07:21:32 -0700, wrote:

On 2 Jul, 02:36, "James Sweet" wrote:
"Gary Tait" wrote in message
4...
wrote in news:1183330881.790940.287160
@n2g2000hse.googlegroups.com:

Are you really saying no-one ever unplugs things withoutout turning
them off first? I really doubt it.

Some equipment simply has no off switch..

Who cares? I unplug and plug in items that are turned on all the time, worst
case you get a little spark, it doesn't cause any problems. It's not hot
enough to pit the plug prongs or contacts.

Its well known that repeated small sparks make a total mess of the
contact surface. This was one of the problems of our olf round pin
system half a century ago.


It is also well known that the properly designed flat blade has a nose
which has sharp enough corners to be the spark point for any arcs. That
means they will all begin or end along those edges, and along the "lead
in" faces of the receptacle. This means that the swept surfaces that
make up the "contact area" of the blades and socket terminals during use
will always be in fine shape.

Our plugs are designed to handle tens of thousands of "hot insertions"
like this. It has to handle some specific number at full rated current
as well. It is part of the design spec for the outlet. This is also why
the ground pin on 3 wire setups is slightly longer. It "makes" contact
before the other "pins" (blades).

On Mon, 02 Jul 2007 07:26:03 -0700, wrote:

On 2 Jul, 03:59, John Larkin
wrote:

lethal. Chewing on cords, especially by pets, is a more serious
hazard, and 240 is a lot worse than 120 there.

Dont think I've ever seen pet chewed cords here, maybe different
checmicals get used in the plastic or something.

120 0r 240 would kill either way.


I don't have access to the statistics, but I really doubt that the
American plug/socket combo is a significant source of fires.

John

http://ieeexplore.ieee.org/xpl/freea...rnumber=148498


NT

Small dogs chew cords. Rabbits certainly do.

With the short electrical path involved, unless the dog/rabbit was
laying on a concrete floor (I have seen this happen) in a
moist/conductive condition, the jolt would likely only teach the lesson
of what not to chew on.

On Sun, 01 Jul 2007 01:16:30 -0500, Wolfi wrote:

2 and 3 prong plugs and
receptacles not having strain relief... they don't need it. If one
remains within the specs for their use, the outlet/plug combo never sees
any particularly high mechanical stresses placed on it.

Having seen plenty of badly bent contact blades on vacuum, TV set, computer &
monitor, power drill and other shop devices' power cords, I strongly disagree.


What part of "if one remains within the specs for their use..." do you
not understand?

On Sun, 01 Jul 2007 10:49:20 -0700, John Larkin
wrote:

On Sun, 01 Jul 2007 01:16:30 -0500, Wolfi
wrote:


I can't comment on that, since I don't have reliable data, but simply asked,
what about the other plain? And it also is much easier to have a slotted pipe
type receptacle, with a steel tape spring surrounding it to guarantee,
constant, long-term contact pressure for a round, mechanically sound, 5mm pin,
which gives solid, equal contact all around its circumference.

I think it has a good reason that the later added third ground pin for the US
system isn't of flat spade shape anymore, but strangely a round one now with,
who would have thought it, 5mm like in the Schuko system as well ;-)

All three pins on the other end of an IEC power cord are flat blades.

John

Yes. Thick, flat blades. Leaning toward square even, but not quite so.

The main reason is that the designers of that chassis end (entry
module) of that chassis connector system wanted large, round nosed
pyramidal points on those strong, flat blades so they could act as good,
repeatable "lead-ins" for the "otherwise only held in by the rubber
squeeze" connector. Also, flat blades do maintain larger swept area of
contact (and therefore safer current carrying capacity) longer than pins
and sleeves after repeated disconnect reconnect cycles. That plug design
was meant for molded on plug assemblies.

Jeez, just think of how huge some strain relieved, metallic, heavy duty
device would be on the back of all our gear over the years.

That was one more benefit of the flat bladed design, was narrower
overall plug size for any given ampacity and voltage compared to what
would have been required for round pins.

jakdedert wrote in
:

bz wrote:
jakdedert wrote in news:e6yhi.8611$09.1625
@bignews8.bellsouth.net:

In some cases it was possible to easily rewired with grounded 12/2
romex from the breaker box. In others, where that was not practical,
the two-prongers were replaced with new outlets--also two prong.

These are still available and should be used if upgrading to a
properly grounded outlet is not done.



If an earth ground is not available, a GFI outlet should be installed
at the beginning of the run and 3 prong outlets along the rest of the
run.

The GFI will trip if a ground fault is present.

The outlets should be marked to indicate that a GFI is installed and
that no earth ground is present.

I believe that this is much safer than using 2 prong outlets and meets
code.



Yes it is, and I'm perfectly aware of the fact. OTOH, replacing with
original equipment is far more responsible than doing what most people
do: replacing with a three prong outlet and either leaving the ground to
float...or worse yet, bonding ground to neutral.

Eventually, all those two-blade outlets will be rewired properly, with
new circuits added. I've done about 25% of the house so far, but it's
slow going....

Understood. I spent quite a bit of time putting GFI's in a house we bought
and are renting out. It was built in the late 40's and expanded several
times, some grounded outlets were installed but grounds were missing on
several. Older parts of the house are on an aux breaker box.

Figuring out what fed what was fun.




--
bz

please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
infinite set.

remove ch100-5 to avoid spam trap

In article om,
says...
On 2 Jul, 03:59, John Larkin
wrote:

lethal. Chewing on cords, especially by pets, is a more serious
hazard, and 240 is a lot worse than 120 there.

Dont think I've ever seen pet chewed cords here, maybe different
checmicals get used in the plastic or something.

Ever see "National Lampoon's Christmas Vacation"?

120 0r 240 would kill either way.

240 is more lethal, though either is enough if they get a good chomp.

--
Keith

Spurious Response wrote in
:

What part of "if one remains within the specs for their use..." do you
not understand?


But when, in the hands of a lay person, does things stay within spec?

On Mon, 02 Jul 2007 17:07:39 -0700, Spurious Response
wrote:

On Sun, 01 Jul 2007 01:16:30 -0500, Wolfi wrote:

2 and 3 prong plugs and
receptacles not having strain relief... they don't need it. If one
remains within the specs for their use, the outlet/plug combo never sees
any particularly high mechanical stresses placed on it.

Having seen plenty of badly bent contact blades on vacuum, TV set, computer &
monitor, power drill and other shop devices' power cords, I strongly disagree.


What part of "if one remains within the specs for their use..." do you
not understand?


If it's bent so much that it's hard to plug in, just bend it back. No
big deal.

John

On Tue, 3 Jul 2007 00:32:33 +0000 (UTC), bz
wrote:

jakdedert wrote in
:

bz wrote:
jakdedert wrote in news:e6yhi.8611$09.1625
@bignews8.bellsouth.net:

In some cases it was possible to easily rewired with grounded 12/2
romex from the breaker box. In others, where that was not practical,
the two-prongers were replaced with new outlets--also two prong.

These are still available and should be used if upgrading to a
properly grounded outlet is not done.



If an earth ground is not available, a GFI outlet should be installed
at the beginning of the run and 3 prong outlets along the rest of the
run.

The GFI will trip if a ground fault is present.

The outlets should be marked to indicate that a GFI is installed and
that no earth ground is present.

I believe that this is much safer than using 2 prong outlets and meets
code.



Yes it is, and I'm perfectly aware of the fact. OTOH, replacing with
original equipment is far more responsible than doing what most people
do: replacing with a three prong outlet and either leaving the ground to
float...or worse yet, bonding ground to neutral.

Eventually, all those two-blade outlets will be rewired properly, with
new circuits added. I've done about 25% of the house so far, but it's
slow going....

Understood. I spent quite a bit of time putting GFI's in a house we bought
and are renting out. It was built in the late 40's and expanded several
times, some grounded outlets were installed but grounds were missing on
several. Older parts of the house are on an aux breaker box.

Figuring out what fed what was fun.

Why don't houses come with schematics?

John

bz wrote:
jakdedert wrote in
:

bz wrote:
jakdedert wrote in news:e6yhi.8611$09.1625
@bignews8.bellsouth.net:

In some cases it was possible to easily rewired with grounded 12/2
romex from the breaker box. In others, where that was not practical,
the two-prongers were replaced with new outlets--also two prong.

These are still available and should be used if upgrading to a
properly grounded outlet is not done.


If an earth ground is not available, a GFI outlet should be installed
at the beginning of the run and 3 prong outlets along the rest of the
run.

The GFI will trip if a ground fault is present.

The outlets should be marked to indicate that a GFI is installed and
that no earth ground is present.

I believe that this is much safer than using 2 prong outlets and meets
code.



Yes it is, and I'm perfectly aware of the fact. OTOH, replacing with
original equipment is far more responsible than doing what most people
do: replacing with a three prong outlet and either leaving the ground to
float...or worse yet, bonding ground to neutral.

Eventually, all those two-blade outlets will be rewired properly, with
new circuits added. I've done about 25% of the house so far, but it's
slow going....

Understood. I spent quite a bit of time putting GFI's in a house we bought
and are renting out. It was built in the late 40's and expanded several
times, some grounded outlets were installed but grounds were missing on
several. Older parts of the house are on an aux breaker box.

Figuring out what fed what was fun.

That's why I just replace the two-prongers as they wear out. New
grounded circuits are home-runs from the breaker box, with new cable and
a new breaker.

jak

On 2 Jul, 16:45, "Dave Plowman (News)" wrote:
In article .com,
wrote:

Who cares? I unplug and plug in items that are turned on all the time,
worst case you get a little spark, it doesn't cause any problems. It's
not hot enough to pit the plug prongs or contacts.
Its well known that repeated small sparks make a total mess of the
contact surface. This was one of the problems of our olf round pin
system half a century ago.

You'd have to explain that. Most of the old round pin sockets were
switched - unswitched was a short lived fashion with 13 amp stuff. At
least in my experience.

The old round pin sockets were far more likely to be overloaded, though.

Round pin systems did not consistently have good contact arrangement,
leading to frequent bad connections between plug & socket, producing
the same type of damage as occurs with unswitched sockets.


NT

wrote:
Round pin systems did not consistently have good contact arrangement,
leading to frequent bad connections between plug & socket, producing
the same type of damage as occurs with unswitched sockets.

Flat plugs came about because of Thomas Edison. He hated Tesla and
refused to use anything but direct current in his electrical systems.
His electrical service company, which supplied New York City,
started out as DC and the large spring loaded plugs were needed.

The originaly were made of two leaf springs, probably brass.

Geoff.

--
Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM
IL Voice: (07)-7424-1667 U.S. Voice: 1-215-821-1838
Visit my 'blog at http://geoffstechno.livejournal.com/

In article . com,
wrote:
On 2 Jul, 16:45, "Dave Plowman (News)" wrote:
In article .com,
wrote:

Who cares? I unplug and plug in items that are turned on all the
time, worst case you get a little spark, it doesn't cause any
problems. It's not hot enough to pit the plug prongs or contacts.
Its well known that repeated small sparks make a total mess of the
contact surface. This was one of the problems of our olf round pin
system half a century ago.

You'd have to explain that. Most of the old round pin sockets were
switched - unswitched was a short lived fashion with 13 amp stuff. At
least in my experience.

The old round pin sockets were far more likely to be overloaded,
though.

Round pin systems did not consistently have good contact arrangement,
leading to frequent bad connections between plug & socket, producing
the same type of damage as occurs with unswitched sockets.

I'd say it depended on the quality of the fitting - given most plug/socket
arrangements have round pins. Including the heavy duty BS4343 type.


NT

--
*Succeed, in spite of management *

Dave Plowman London SW
To e-mail, change noise into sound.

Am 02.07.07 19.20 schrieb Spurious Response:
On Sun, 01 Jul 2007 10:49:20 -0700, John Larkin
wrote:

On Sun, 01 Jul 2007 01:16:30 -0500, Wolfi
wrote:

I can't comment on that, since I don't have reliable data, but simply asked,
what about the other plain? And it also is much easier to have a slotted pipe
type receptacle, with a steel tape spring surrounding it to guarantee,
constant, long-term contact pressure for a round, mechanically sound, 5mm pin,
which gives solid, equal contact all around its circumference.

I think it has a good reason that the later added third ground pin for the US
system isn't of flat spade shape anymore, but strangely a round one now with,
who would have thought it, 5mm like in the Schuko system as well ;-)
All three pins on the other end of an IEC power cord are flat blades.

You're talking about this IEC (http://de.wikipedia.org/wiki/IEC_60309) power
connector, rated from 16A up to 250A @690VAC? ;-)
But it also uses round pins, not flat ones.

John

Yes. Thick, flat blades. Leaning toward square even, but not quite so.

Or should you mean that type, which is used for computer monitors and -power
supplies?
If so, then you surely noticed the lousy Ampère rating of mere 10A for it,
which is just 2.3kW, rather than the 3.68kW which you have with a 16A
connector system?

The main reason is that the designers of that chassis end (entry
module) of that chassis connector system wanted large, round nosed
pyramidal points on those strong, flat blades so they could act as good,
repeatable "lead-ins" for the "otherwise only held in by the rubber
squeeze" connector. Also, flat blades do maintain larger swept area of
contact (and therefore safer current carrying capacity) longer than pins
and sleeves after repeated disconnect reconnect cycles. That plug design
was meant for molded on plug assemblies.

Jeez, just think of how huge some strain relieved, metallic, heavy duty
device would be on the back of all our gear over the years.

That's not required at all, but all those connector standards, Schuko, Euro,
IEC 60309, IEC 60906-1 and the forementioned 3-contact socket/plug system used
for computer monitors and SMSP have the removable parts case dive into the
fixed mounted one, taking off mechanical stress from the pins and burden it
onto the housing.
And exactly this point is *not* true for the U.S. style connector system and
this is one of the reasons, why I have quite a low opinion of it.

That was one more benefit of the flat bladed design, was narrower
overall plug size for any given ampacity and voltage compared to what
would have been required for round pins.

Well, it must have some reason that the international standard 230 V household
plug system, specified under IEC 60906-1, uses round pins as well, not flat
ones. http://en.wikipedia.org/wiki/IEC_60906-1

Am 02.07.07 19.07 schrieb Spurious Response:
On Sun, 01 Jul 2007 01:16:30 -0500, Wolfi wrote:

2 and 3 prong plugs and
receptacles not having strain relief... they don't need it. If one
remains within the specs for their use, the outlet/plug combo never sees
any particularly high mechanical stresses placed on it.
Having seen plenty of badly bent contact blades on vacuum, TV set, computer &
monitor, power drill and other shop devices' power cords, I strongly disagree.


What part of "if one remains within the specs for their use..." do you
not understand?

I don't know. Apparently those specs are either missing completely on those
devices' power cords I came across so far, or they are written so tiny, that
not a single one of their owners could read them either.

And, If I plug in that forementioned air compressors power cord and it comes
out of the socket again just by the weight of the cable pulling on it, which
spec applies for it then?

It just prooves my point that it is a poor system having all the weight/pull
on a cable being put on the electric contacts rather than to the largest
degree on the housing.

Am 02.07.07 21.35 schrieb John Larkin:
On Mon, 02 Jul 2007 17:07:39 -0700, Spurious Response
wrote:

On Sun, 01 Jul 2007 01:16:30 -0500, Wolfi wrote:

2 and 3 prong plugs and
receptacles not having strain relief... they don't need it. If one
remains within the specs for their use, the outlet/plug combo never sees
any particularly high mechanical stresses placed on it.
Having seen plenty of badly bent contact blades on vacuum, TV set, computer &
monitor, power drill and other shop devices' power cords, I strongly disagree.

What part of "if one remains within the specs for their use..." do you
not understand?


If it's bent so much that it's hard to plug in, just bend it back. No
big deal.

Oh yes, it easily becomes a big deal as in case of an electric floor heater.
Some moron in the past had moved it around so violently while being plugged
in, that both contacts had been bent to at least 45° off direction befor it
came out of the socket and when I tried to put them straight again, one of
them broke off. I had quite a hard time to find a screw on replacement plug.

On Tue, 03 Jul 2007 08:54:53 -0700, John Larkin
wrote:

On Tue, 3 Jul 2007 00:32:33 +0000 (UTC), bz
wrote:

jakdedert wrote in
t:

bz wrote:
jakdedert wrote in news:e6yhi.8611$09.1625
@bignews8.bellsouth.net:

In some cases it was possible to easily rewired with grounded 12/2
romex from the breaker box. In others, where that was not practical,
the two-prongers were replaced with new outlets--also two prong.

These are still available and should be used if upgrading to a
properly grounded outlet is not done.



If an earth ground is not available, a GFI outlet should be installed
at the beginning of the run and 3 prong outlets along the rest of the
run.

The GFI will trip if a ground fault is present.

The outlets should be marked to indicate that a GFI is installed and
that no earth ground is present.

I believe that this is much safer than using 2 prong outlets and meets
code.



Yes it is, and I'm perfectly aware of the fact. OTOH, replacing with
original equipment is far more responsible than doing what most people
do: replacing with a three prong outlet and either leaving the ground to
float...or worse yet, bonding ground to neutral.

Eventually, all those two-blade outlets will be rewired properly, with
new circuits added. I've done about 25% of the house so far, but it's
slow going....

Understood. I spent quite a bit of time putting GFI's in a house we bought
and are renting out. It was built in the late 40's and expanded several
times, some grounded outlets were installed but grounds were missing on
several. Older parts of the house are on an aux breaker box.

Figuring out what fed what was fun.

Why don't houses come with schematics?

John

The number of complete dopes that ignore the "No User Serviceable Parts
Inside" notice and open their consumer product up anyway is already
staggering, and some of those still come with schematics.

I am sure this would cause an increase in house fires around the
nation.

On Tue, 03 Jul 2007 15:38:29 -0500, Wolfi wrote:

All three pins on the other end of an IEC power cord are flat blades.

You're talking about this IEC (http://de.wikipedia.org/wiki/IEC_60309) power
connector, rated from 16A up to 250A @690VAC? ;-)
But it also uses round pins, not flat ones.


No, silly. He was talking about the STANDARD US 120V IEC cord used on
nearly everything made these days, from dongles to 70" FPDs.

http://www.coleparmer.com/techinfo/t...ugs.htm&ID=346

On Tue, 03 Jul 2007 15:38:29 -0500, Wolfi wrote:

If so, then you surely noticed the lousy Ampère rating of mere 10A for it,
which is just 2.3kW, rather than the 3.68kW which you have with a 16A
connector system?


If I do not need 16 A power feeds as a result of not having any 16 A
power requisites, then why would I need a 16 A cord and receptacle
system?

On Tue, 03 Jul 2007 15:38:29 -0500, Wolfi wrote:


Well, it must have some reason that the international standard 230 V household
plug system, specified under IEC 60906-1, uses round pins as well, not flat
ones. http://en.wikipedia.org/wiki/IEC_60906-1

That thing has ONLY been planned for adoption by BRAZIL!

You say "international standard", but the part of that that makes it
"international" is the fact that an international organization published
it. Other than that, it is quite obscure.

There are many reasons for choosing round or flat contacts. There are
many connector systems... many different connector system designs.

One factor is temperature.

Here is a great place to get some power cord trivia:

http://www.accesscomms.com.au/reference/IEC320.htm

That is just the 320 section.

On Tue, 03 Jul 2007 15:45:34 -0500, Wolfi wrote:

I don't know. Apparently those specs are either missing completely on those
devices' power cords I came across so far, or they are written so tiny, that
not a single one of their owners could read them either.


So, now you want to convince everyone here that the force needed to make
those blades bend was within the operational specs for the connector
system?

Use a little common sense, or don't be a dork, take your choice.

On Tue, 03 Jul 2007 15:45:34 -0500, Wolfi wrote:

And, If I plug in that forementioned air compressors power cord and it comes
out of the socket again just by the weight of the cable pulling on it, which
spec applies for it then?


If you are plugging some bent up plug into a power socket, you are an
idiot for not servicing the plug before using the product it was attached
to. Oh, and if you are seeing perfectly normal plugs coming out of an
outlet, YOU need to service the outlet.

How's that for a spec, dip****? or... How's that for getting
yourself spec'd, as a dip****, dip****?