IEC leads, the wires just seem to get thinner and thinner

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I remember a thread on here a couple of years back about under-rated
cables used on IEC leads, unfortunately the situation seems to be
getting worse rather than better.


Just received an IEC lead with a computer power supply, the lead in
question is 1m long, and has a USA plug on one end, and a standard IEC
socket on the other end.  The socket is clearly marked 10a 250v.  The
cable is marked as 0.5mm squared.  The entire 2 layer 3 core insulated
cable is approximately 5mm thick, and has a measurement of about 0.5
ohms on each of the 3 wires from end to end (which gives about 1 ohm
total resistance in the circuit).

Just looking at how thin the cable was, and the light weight of it
alarmed me.


Compared with a 2m length of approved (Cable marked: FUJIKURA AS3181
LIC: 1025)  1.0mm square 3 core cable (approx 7.5 mm diameter) fitted
with similar connections, you get less than .1 ohm per core using the
same meter (fluke 87).  (note that this is for 2m - not 1m - I didnt
have a 1 metre length handy to do a comparison)


Considering that the thin cable was obviously intended for use in the
US 120v market, and therefore the same type of appliance used there
will be drawing DOUBLE the current of our 240v system, this makes
matters even worse and a serious risk of fire if used on a 10a
appliance.


Re: IEC leads, the wires just seem to get thinner and thinner



"kreed"

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** That was my thread, back in August 2002.

With heckling by " Miro " and generous assistance by Ross Herbert from WA.


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**  Whaaaaaaaaaattttttt   ??????

   You sure the resistance value is that high ?


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**  Sounds like the one I found  -   but much worse.

The wire inside that was not even copper, but a much higher resistance alloy
!!


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** 1 sq mm copper wire has only  17 or 18 milliohms per metre  !!

 That amount will handle  7.5  to 10 amps OK  in a two conductor lead.


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**  Absoblooominglutely !!!!!

Care to check those resistance values again with more accuracy  ?

Maybe use a 1 amp DC source ( bench PSU in current limit) and measure the
voltage drop along the cable.

Was the supplier in Aussie ??

Please keep us informed.




......   Phil




Re: IEC leads, the wires just seem to get thinner and thinner


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I'd believe that.

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madness.


cheap crap, probably made in China. I got a plug board in China
recently; in addition to only having 5-6 strands of copper per cable
(but very thick insulation - obviously plastic is cheaper than copper),
the prongs on the 3-pin plug were about 0.7mm thinner than normal - so
much that the plug falls out of ordinary wall sockets. like hell its
10A. I havent measured the resistance, as its not here right now...

And a mate who runs a company in China making thumbprint scanners asked
me to look at some plug-packs they had been having trouble with. I
hacksawed one apart, and found some really interesting stuff. Like the
switching transistor nut (no spring washer) was loose, the soldering was
appalling, and the construction was such that the P,N wires wrapped
around the switching transistor and 3-leg-gapped flyback transformer.
Small wonder they were dying, and like hell it passed CE - they just
printed up a label that said it did. Be afraid, be very afraid.

AIUI DSE has had some problems in the past with allegedly EMC compliant
gear not actually complying; apparently they now put all of their
products thru compliance testing in Aussie/NZ testing labs.

companies that import direct from China really need to verify that they
are getting what they ask for, and that it *actually* meets the relevant
standards.

Whats even scarier is going to a place like Saige (sp?) in Shenzhen,
huge components/computers place - 3 Floors of electronics components,
another 6 or so of computer stuff. Where I saw people recycling ICs -
straightening leads, cleaning with erasers, putting into tubes, all sans
antistatic precautions. And where the aforementioned plug-packs were
sourced. I wonder how many AU/NZ parts suppliers shop there?

Cheers
Terry

Re: IEC leads, the wires just seem to get thinner and thinner


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After the silly shitfight that happened over this in 2002 mostly by
people who didnt seem to know - (and worse still didnt want to know) -
the basic laws of physics or ohms law, I Decided to do a "real world"
test on the cable, using a "Bi-Lo" electric Jug.   The jug was labelled
at 2400w @ 240v), however measurement of the element resistance at room
temperature showed 27.5 ohm and the mains voltage used was 237.5v so
this would mean that the jug was drawing 8.64 A  from the mains.  (The
measured current was actually 8.63a)

A fluke 87 meter was used for the measurements shown

Firstly tried measuring the voltage drop along the 2m length of
approved IEC cord mentioned in the original post.  This showed a
voltage drop of  0.52v across each conductor when the jug was turned on
from cold.  This indicated a cable resistance of approx. 30 milliohm
per metre. (including the resistance of the connectors molded onto the
cord).  (I suppose we can assume an approximate 12 milliohm loss in the
plug, socket etc in the circuit from this ?)

With the jug again at room temperature the suspect cable was then
connected in the circuit.  This showed an alarming 5.3v (note 5.3v not
0.53v) drop along each core of the 1m lead when the jug was switched on
from cold.  According to my calculations, this shows a cold resistance
of the cable assembly of around 0.61 ohm (about 0.49 ohm if we take the
connector losses mentioned above into account ?)

Within 30 seconds, the cable was getting quite warm, and within a
minute, small amounts of smoke were noticed. The mains power was shut
off immediately, and the water in the jug was nowhere near boiling
point.

I stripped back about 1.5 inch of outer insulation from the cable, so
as to look at the state of the internal conductors, they were all black
in colour, and looking at the copper internal of one of the wires, it
looked like copper to me, and it readily took solder when I tried it.
However it was thinner even than than the normal grey cheap & nasty
figure "speaker wire" that is often sold at major electronic retailers.


I let everything cool down, and tried again, the meter was connected in
parallel with one core of the cable in order to measure the voltage
drop in real time.   The jug was then switched on and the meter again
read 5.3v.  it took a couple of minutes for the jug to start to reach
boiling point, and in that time the voltage loss steadily rose from 5.3
v to 5.58 v   The cable began to smoke and melt, and I observed the
insulation on the exposed inner wires beginning to melt and stick to
the others,  I turned off the power as I had no desire to short circuit
the workshop supply. One part of the cable had sat in a circle over
itself, and sat over another part of the cable, these 2 parts had
softened sufficiently to stick themselves together quite well

The bodgy cable was labelled "3 x 0.5mm sq"

Remembering that this test was at 8.6a, and not the full 10a, it would
have been a lot worse if the cord was used on a 10amp appliance, or on
a 10a electric jug in an area where the mains was around 250-260v
(which does happen)

The same test done (from cold to boiling) with the "real" 1.0mm sq lead
showed no significant cable warming.


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Came from Australian Ebay seller, it was a PC based commercial arcade
(video game) board system.  It included a standard "off the shelf" 300w
ATX supply, and this dodgy IEC cable.


  

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Re: IEC leads, the wires just seem to get thinner and thinner



"kreed"
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** The scenario you describe here is close to IDENTICAL to that with the IEC
cable I saw back in 2002  -  maybe even a tad worse.

With around 300 milliohms pre metre of conductor -  the equivalent copper
cross-section is only *  0.06  sq mm *  or 13 times less than the minimum
required by law   !!!!!!

Gotta be the same high resistance ( bronze wire ? )  alloy I saw.

Must be a lot of these horrors floating about, packed in with Chinese
electronic items.


BTW:

I just checked out the IEC lead that came with my DSE Q1803 CRO  -   no
problems, had all the right markings and passed the "jug test" easily.

Responsible importers  ARE  aware of their legal obligations re IEC
appliance leads and simply REMOVE any non-approved ones and replace them in
the packing.




.......   Phil






Re: IEC leads, the wires just seem to get thinner and thinner


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SO you replaced it ?

Re: IEC leads, the wires just seem to get thinner and thinner


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I noticed the same thing with a cheap set of automotive jumper leads,
really thick insulation but about 1mm square cross section conductor.
Not only that but the bulldog clips had high resistance crimp
connections and the whole think would get too hot to touch if you put
any sort of a load on it.

Friday

Re: IEC leads, the wires just seem to get thinner and thinner



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Although this is related to a US style cordset this is a serious issue that
is becoming more prevalent.  As China uses the same domestic outlet style as
AU/NZ there are more cords being sourced and supplied from there that do not
meet the basic AU/NZ standards for the cordset and mains plug.  There is
also no understanding about light, ordinary or heavy duty ratings or about
the hot condition ratings for the connectors.

I would guess the 10A rating you refer to is stamped or embossed on the plug
face and not the cord, which is very common.  Looking inside many of the
generic ATX computer cases that are fitted with PSUs will often yeild one of
these unapproved (and unapprovable) cordsets (in a bag) which are intended
for Chinese domestic consumption.




Re: IEC leads, the wires just seem to get thinner and thinner



"Dave"  ???   Not  Dave  Castels ????


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** No IEC lead can be LEGALLY sold or supplied in Aussie without receiving
type approval.

Approved leads must use a 3 core cable with at least  0.75 sq mm copper
conductors.

Such a lead runs comfortably at 7.5 amps and a tad warm at 10 amps.

So, despite there being a variety of conductor gauges, no lead is dangerous
in use.



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**  The only meaningful markings are the APPROVAL code numbers which must be
marked on each plug and the cable.

These numbers start with letters indicating the Australian state where type
approval was obtained,  ie   V =  Victoria, N = NSW,  Q =  Queensland  etc.


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**  I really doubt the Chinese are so utterly reckless as to consider such
leads as mentioned by the OP legal trade there.

 The Chinese " love their children  too "   -  you know.



.......  Phil




Re: IEC leads, the wires just seem to get thinner and thinner



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No.


Sorry, maybe I didn't explain it well enough.  Often the plugs have the
voltage and current rating embossed into the plug-face,  and for approved
types the approval number will be too.  So the 10A rating may be for the
plug but not the cord.  The plug molder and the cord maker will usually not
be the same factory, and neither of them will have much of an idea about the
true parameters of the products as they will have copied it from someone
else anyway.  The problem gets worse as maker(x) copied maker(3) who copied
maker(2) who copied maker(1) who was an OEM contract maker.

The chinese domestic market plugs look the same as AU/NZ ones but there is
no approval marking.  The Chinese ones are also appearing with insulated
pins although they are not required in China.   These are just as DANGEROUS
as the under-rated cords because the insulated pins snap off in the socket,
leaving exposed metallic parts.

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It all comes down to lack of knowledge rather than intent.  The cords
mentioned above are indeed sold within China in large numbers quite legally.
For an ITE device such as a PC the cord will not cause a problem due to
overheating.  As pointed out in another post (by you I think) the problem
arises when the cord finds its way elsewhere.  No doubt time will tell that
this is a problem over there and as the marketplace matures they will put
better regulations put in place.




Re: IEC leads, the wires just seem to get thinner and thinner

"Dave the Context  Snipper from Hell
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** No   -   you were just plain wrong.

Approved leads must use a 3 core cable with at least  0.75 sq mm copper
conductors.

Such a lead runs comfortably at 7.5 amps and a tad warm at 10 amps.

So, despite there being a variety of conductor gauges, no lead is dangerous
in use.




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 **  That is   COMPLETELY  ASININE   CRAP    !!!

     Smacks  APPALLINGLY  of   RACISM  too.



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**  Bollocks.



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**  I really doubt the Chinese are so utterly reckless as to consider such
 leads as mentioned by the OP legal trade there.

The Chinese " love their children  too "   -  you know.

Not matter what some anonymous fuckheads like  " Dave "  will have you
believe .





.......   Phil





Re: IEC leads, the wires just seem to get thinner and thinner

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Well I only bother including thr bits relevant to the discussion, the rest I
agreed with or had no comment on.

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Since you kept this bit in I assume you believe it is significant.  Two core
leads are OK providing they are not attached to three position connectors...
yes I am sure you know that but there are others who don't.

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dangerous

Your left the word APPROVED out.  In which case I agree, except for
counterfeit products.

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consumption.

I'll leave all this in. Since your shouting it I guess it has to be
important..

Of course the Chinese love their kids too... and although I know precisiely
what you mean by it, ignorance or plain lack of knowing better, kills plenty
of people every day in all kinds of fields. As for me being racist, I showed
this to one of our chinese engineers today and asked him... he doesn't think
so.... and as for my comment (> > It all comes down to lack of knowledge
rather than intent.) as he put it "they don't know what they don't know" and
of course neither do any of us if you look at it logically.

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Unfortunately the case just isn't that simple.  In Au we have a minimum
conductor size (as you pointed out previously) which effectively outlaws the
sale of light duty cords fitted with certain types of connectors (such as
IEC60320 Type C.13).  However although China does require certification of
cords they have a much less restrictive definition.  See
www.sccc.ch/download/info/ccc/20030618_CCC_Regulations.pdf

Experience is what led to the declaring definition being worded the way it
is here.  As the CCC scheme matures further these sorts of issues may get
included.  UL have a similar approach to AU in that they have additional
criteria they apply during type certification.

I will add this last bit below simply because I find it very important to
counter what you inferred... the inference being that because the Chinese
love their kids they wouldn't do anything to endanger them.

A large part of my business involves correcting similar assumptions.
Specifically companies go to the various trade shows and buy product on the
basis that it must be OK otherwise the vendor wouldn't be able or allowed to
sell it.  This assumption costs AU importers millions of dollars per year -
looking through www.recalls.gov.au will give an idea of what happens to a
variety of products which are imported and sold based on assumptions the
factory must know what they are doing.  What appears on the recall site is
but a fraction of what is recalled/reworked/repaired for reasons other than
saftey issues.

I really think you have got the right idea sometimes Phil and some of the
stuff you post is sensible and has history to back it up.  Normally I
wouldn't even bother replying to a circular argument but if there are people
thnking about importing stuff from anywhere using an assumption "it'll be
alright because the factory says it is", and because "they already sell lots
elsewhere", the buyers needs to ensure they have a decent product assessment
program to verify all is indeed OK.

I am only anon in here to avoid our servers getting bombed by spam.  If
anyone wants to contact me I am happy to help, all they have to do is ask
and I'll provide a working ISP based email address.




Re: IEC leads, the wires just seem to get thinner and thinner


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Try pulling some of these 500 watt psu apart , 5v rails on .6 mm wire.

Re: IEC leads, the wires just seem to get thinner and thinner



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Best I've seen was an appliance from India
(sensor system base station) , they used 22 gauge
for the internal 240V wiring (had a current draw  1A).
Had crimped spade lugs for some terminations , soldering for others.
All internal wiring was the same colour.

The aluminium front panel provided the connection
between the frame , case and ground.

The power supply was a modified computer psu
with the iec socket removed from the power supply
and directly wired to the iec socket on the back of the case.

The soldering on the psu was very bad and there was no grommet
on where the wires came through the case.

Amazing thing was when stuck on an appliance tester
it withstood 500V 25A and passed the earth tests.

Alex



Re: IEC leads, the wires just seem to get thinner and thinner



"Alex Gibson"

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 ( snip silly whinge)


** Yawn  -  that is not a life threatening hazard to anyone.

An IEC lead with high resistance wire in it damn well IS   !!!!

No mater what it was originally sold with, an IEC type general purpose
appliance lead can and will be transferred to another appliance, at some or
other,  time that draws 10 amps of AC current.

The unsuspecting owner of the illegal ones will then have either a fire on
their hands or else a very serious electrocution hazard.

If the culprits supplying such illegal IEC leads can be identified and
located, the relevant state government energy safety authority will ( once
informed ) act very promptly to stop them and or prosecute them.

Ross Herbert and myself have found the state authorities take a  VERY
SERIOUS  view of this kind of public safety offence.

I bet the courts will too.



......   Phil





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That's very high, I get  0.6 ohms for about 10m of 24AWG telephone wire.

Bye.
   Jasen

Re: IEC leads, the wires just seem to get thinner and thinner




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10m of 24AWG telephone wire.
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it is, but 10m of telephone wire might at least stand a better chance
of dissipating the heat over a 10m length than this crap "mains cable"


Re: IEC leads, the wires just seem to get thinner and thinner



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It comes down to price, I have a mate who sells these things in Europe. He
used to have a small factory where he made cables, now he buys container
loads from China. The whole assembly costs less than he can buy one of the
plugs for, parts, labour, shipping and duty included. Somewhere corners
have to be being cut, but, as he says, he would have no market for the home
grown ones, they cost a dollar more.

Well I dont think that is quite true, I saw a one metre IEC cable in a pommy
Hi Fi mag, it was 450 pounds Sterling. However the review reckonned it was
worth it, as it gave a much more fluid sound and an expanded sound stage
whatever that means.

Keith




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