Re: Internal wiring of USA v UK mains plug

[Spurious Response]

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.



http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=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.

 

[Spurious Response]

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?

 

[Spurious Response]

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.

 

[bz]

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.

[email protected] remove ch100-5 to avoid spam trap

 

[krw]

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.

 

[Gary Tait]

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?

 

[John Larkin]

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

 

[John Larkin]

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

 

[jakdedert]

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

 

[[email protected]]

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

 

[Geoffrey S. Mendelson]

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.

 

[Dave Plowman (News)]

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.

 

[Wolfi]

Am 02.07.07 19.20 schrieb Spurious Response:
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.

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

 

[Wolfi]

Am 02.07.07 19.07 schrieb Spurious Response:

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.

 

[Wolfi]

Am 02.07.07 21.35 schrieb John Larkin:

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.

 

[Spurious Response]

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.

 

[Spurious Response]

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/techinfo.asp?htmlfile=IEC320ModularPowerCordsAndPlugs.htm&ID=346

 

[Spurious Response]

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?

 

[Spurious Response]

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.

 

[Spurious Response]

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.