Author Topic: 4 out of 5 vendors are scamming people with wrong crosssection of cables  (Read 6595 times)

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Offline eTobeyTopic starter

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I have ordered cables from 5 different places (Germany). 4 of them had sent me cables that had about 20% less crosssection than advertised. I measured via visual and electrical methods, so there is no doubt about my measurements. One one ocassion, the outer diameter had me feel that it was to little, and sure enough it was...

Have you ever checked on the cross section?

« Last Edit: May 01, 2024, 06:37:50 pm by eTobey »
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Offline ejeffrey

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What kind of cables?  Power or signal?  Were they advertised to conform to a particular industry spec or just a specific size?

 
 

Offline eTobeyTopic starter

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What kind of cables?  Power or signal?  Were they advertised to conform to a particular industry spec or just a specific size?
I wrote in this section of the forum, because it has the word "power" in it.  ;)

But i also found in one delivery where i ordered a few 0.35mm2 cables, one cable to beeing substantially less.

Seemingly, many people just trust what there is advertised. But you cant trust anything nowadays...

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Online mariush

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Do they use the exterior diameter (with insulation), or the inner diameter (as if you stripped)

On stores like Digikey , Newark and others you get a datasheet for the cable where it tells you how many strands of wires are used, and what's the gauge of each strand.

See for example https://www.digikey.com/en/products/filter/single-conductor-cables-hook-up-wire/474  you see there a column with number of strands and thickness of each strand


edit : you seem to be in Germany so TME.eu may work better : https://www.tme.eu/en/katalog/wires-and-cables_112533/

You can see all the parameters at the Stranded cables section : https://www.tme.eu/en/katalog/single-core-cable-strand_100147/
« Last Edit: April 28, 2024, 06:29:56 pm by mariush »
 

Online Stray Electron

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I have ordered cables from 6 different places (Germany).
Have you ever checked on the cross section?


   Where were the cables made?   Undersizing of wire and cables made in China has been widely reported on this and other sites.   A lot of the wire is also reported to be made some kind of junk alloy that isn't solderable.  I've learned to not trust the ratings of anything made in China.

  A few years ago my 730 pound Miller welder got dumped unto the ground when the frame of my Chinese made 900 pound rated trailer bend under the load and within 30 seconds of placing the welder on it and before we had moved it even an inch.
 

Offline eTobeyTopic starter

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   Where were the cables made?   Undersizing of wire and cables made in China has been widely reported on this and other sites.   A lot of the wire is also reported to be made some kind of junk alloy that isn't solderable.  I've learned to not trust the ratings of anything made in China.

I dont know, and the vendor wont tell me of course.

Only 2 of them were amazon and ebay (not chinese - and seemingls reputable ones), but the other had their own websites and did not have bad ratings. I think they are not aware of it either. One of them got quite furious, as he strongly insisted it was 6mm2 even though i told him two measurement methods showed otherwise (This one sold photovoltaik stuff).

Still my question is unanswered:
Have you ever checked on the cross section?
« Last Edit: April 28, 2024, 06:44:19 pm by eTobey »
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Offline Karel

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Quote from: eTobey
Still my question is unanswered:
Have you ever checked on the cross section?

No, because I order from Digikey/Mouser/Farnell.
 

Online Bud

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  A few years ago my 730 pound Miller welder got dumped unto the ground when the frame of my Chinese made 900 pound rated trailer bend under the load and within 30 seconds of placing the welder on it

Must observe the 11th Commandment: "Thou shalt downscale all Chinese specifications by a factor of 2".
Facebook-free life and Rigol-free shack.
 
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Offline eTobeyTopic starter

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No, because I order from Digikey/Mouser/Farnell.
When there are so many cases of wrong cross sections, i would be very curious not caring about big names.
"Sometimes, after talking with a person, you want to pet a dog, wave at a monkey, and take off your hat to an elephant." (Maxim Gorki)
 

Online Stray Electron

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   Where were the cables made?   Undersizing of wire and cables made in China has been widely reported on this and other sites.   A lot of the wire is also reported to be made some kind of junk alloy that isn't solderable.  I've learned to not trust the ratings of anything made in China.

I dont know, and the vendor wont tell me of course.

Only 2 of them were amazon and ebay (not chinese - and seemingls reputable ones), but the other had their own websites and did not have bad ratings. I think they are not aware of it either. One of them got quite furious, as he strongly insisted it was 6mm2 even though i told him two measurement methods showed otherwise (This one sold photovoltaik stuff).

Still my question is unanswered:
Have you ever checked on the cross section?

   I've never measured any that I'm aware of, but I've seen dozens of Chinese made wires and cables (including steel cable, aka "wire rope") that were obviously smaller than it was labeled.  Personally I haven't bothered to measure any of the Chinese electrical stuff because, so far, I've been able to buy reputable American made brands that I know that I can trust.  I've learned the HARD WAY, so whenever it's something that matters, I now go out of my way to good American, Japanese or western European brands even though they cost a lot more than the Chinese stuff.

   I DID look at probably 40 different lots of wire rope and I did measure a lot of it and ALL of the Chinese made stuff was much smaller than claimed.  Also I really have no idea what kind of steel it was made of so I finally bought 1000 feet of US made wire rope surplus.  My off road vehicle (1952 Dodge m-37) weighs almost 7,000 pound unloaded and calls for 1/2" IPS (Improved Plow Steel) wire rope that is rated for a 27,000 pound working load.  I found the stuff that the Chinese were selling was less than 7/16" and it BROKE at about 9,000 pounds. 

   it's the same story as my Chinese made trailer, it will almost meet the stated load but there is NO safety margin. 
 

Offline ejeffrey

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No, because I order from Digikey/Mouser/Farnell.
When there are so many cases of wrong cross sections, i would be very curious not caring about big names.

I've never measured explicitly, but if you told me you bought genuine belden wire from and authorized distributor and it was smaller than what it says on the box I'd be surprised and I would go measure some of the wires in my shop.  The fact that 5 different wires purchased from random resellers on Amazon or eBay were counterfeit it doesn't surprise me at all.
 

Offline thermistor-guy

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...
   it's the same story as my Chinese made trailer, it will almost meet the stated load but there is NO safety margin.

There's a Chinese EE located near me, running a transformer rewinding business. He's from Shanghai. Many years ago, he told me that
Chinese electronics are made to a price, and they will only just meet spec. (if at all).

He went on to say that, unlike US or EU equipment, Chinese-brand equipment will not have any overload capability, not even
short-term overload.
 

Offline f4eru

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I measured via visual and electrical methods, so there is no doubt about my measurements.
Pleaae publish your measuremenets.
 
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Offline Siwastaja

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Have you ever checked on the cross section?

Another interesting question would be, how did you measure it? I ask because measuring cross section of a multi-stranded wire is not trivial at all. Which is also why, to answer your question: I have never checked. I think the risk of me measuring incorrectly would be larger than the manufacturer lying.

One thing to consider is also tolerances. In engineering, everything comes with a tolerance. Manufacturer's job is to guarantee their product is within tolerances. If they can improve the manufacturing process, they can save costs by making undersized product which is still within tolerances, and no one would be lying.
 

Offline eTobeyTopic starter

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... I ask because measuring cross section of a multi-stranded wire is not trivial at all. Which is also why, to answer your question: I have never checked. I think the risk of me measuring incorrectly would be larger than the manufacturer lying.

Current, voltage drop and ust a few calculations, and then you have the cross section. Nowadays with internet i would call this trivial.

I could not find the very same measurments, but i can give you an example, that is as good. (Scamed by the PCB manufacturer, as he did not mention a tolerance of 20%. Seems to be a chinese thing, yes).
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Offline mzzj

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... I ask because measuring cross section of a multi-stranded wire is not trivial at all. Which is also why, to answer your question: I have never checked. I think the risk of me measuring incorrectly would be larger than the manufacturer lying.

Current, voltage drop and ust a few calculations, and then you have the cross section. Nowadays with internet i would call this trivial.

I could not find the very same measurments, but i can give you an example, that is as good. (Scamed by the PCB manufacturer, as he did not mention a tolerance of 20%. Seems to be a chinese thing, yes).
Maybe trivial question but what did you use for reference copper conductivity value?
100% IACS gives different results than actual cabling standard IEC 60228

Out of curiosity I measured bunch of wires and bit suprisingly worst offender is single strand 1.5mm2 cable from some european manufacturer: (every cheapo chinese wire passes the  IEC 60228)
« Last Edit: April 29, 2024, 06:24:25 pm by mzzj »
 

Offline eTobeyTopic starter

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Maybe trivial question but what did you use for reference copper conductivity value?

Out of curiosity I measured bunch of wires and bit suprisingly worst offender is single strand 1.5mm2 cable from some european manufacturer
I used the standard values that were in the calculator.

How did you measure the resistance?

In the end, i also received cables that had the values i calculated, so there is nothing wrong with my calculations.
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Offline ejeffrey

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You are being pretty evasive, not providing a example product, data sheet, measurement, photo, or really anything supporting your claim except for somehow a microscope image that appears to be of a PCB trace and which seems completely irrelevant?  So it's no surprise everyone is being skeptical of your measurements. 

If you can't provide numbers and references there isn't really anything for anyone here to say.
 
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Offline mzzj

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How did you measure the resistance?

In the end, i also received cables that had the values i calculated, so there is nothing wrong with my calculations.
Mystery wire, mystery supplier, mystery method and mystery calculator.

Your calculator probably uses theoretical values calculated with 100% IACS conductivity and manufacturers aim close to IEC 60228 maximum value as they can reliably get as it provides best profits.
Note that IEC 60228 has different maximum resistance for same cross section area depending if it fine or coarse stranded wire. Difference between fine-stranded wire and 100% IACS is almost 15%

I used 4-wire measurement with 1A current supplied by Agilent 6632B power supply, voltage loss measured with dvm, cable lenght with tape measure.

Seemed like good idea to twist the wire strands tightly and place the kelvin wire connections with at least 20mm gap on the wire.
Without twisting and some gap between the kelvin wire connections the results were bit unstable, probably due to unstable connection and current distribution between wire strands.
« Last Edit: April 29, 2024, 09:33:49 pm by mzzj »
 

Offline jonpaul

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We use only genuine Belden wire and cable as our work is important

The Chines commi junk eg eBay, Ali express is penny wise and pound foolish.

Try a magnet on the ChiCom wire to detect the iron.

Return for refund all the junk

Jon
Jean-Paul  the Internet Dinosaur
 
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Offline Siwastaja

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I used the standard values that were in the calculator.

You were asked what resistance value you used. Your answer is "the one in the calculator". What the heck even is "the calculator"?

Given this glaring lack of scrutiny and total absence of any scientific mindset, I'm 99% sure you just did something wrong.
 

Offline Siwastaja

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Seemed like good idea to twist the wire strands tightly and place the kelvin wire connections with at least 20mm gap on the wire.
Without twisting and some gap between the kelvin wire connections the results were bit unstable, probably due to unstable connection and current distribution between wire strands.

Indeed, current sharing between the strands in stranded wires is a big question mark. People incorrectly assume the strands form low-resistance connections to each other everywhere within the wire, but this isn't true, there isn't enough pressure (if there was, then the wire would not be flexible anymore, the whole point of the stranded wire). Therefore how the strands are terminated at both ends is hugely important if one wants maximum possible current capability (and in this case, correct measurement result).
 

Online Geoff-AU

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Must observe the 11th Commandment: "Thou shalt downscale all Chinese specifications by a factor of 2".

Nah, I decline your invitation to participate in the race to the bottom.

The end game for this starts at 10x spec inflation and ends at the moon (if not further).  60dBi antennas, 300dB car horns, 9000mAh 18650 cells… I’ve seen all of those for sale and you can keep em.  I’ll buy real specs from real vendors thanks.
 

Offline eTobeyTopic starter

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If you can't provide numbers and references there isn't really anything for anyone here to say.
It was never my intention to prove anything. There is also a question in my original post that can be answered.

I had another look, and the best i could find, that one supplier claimed it to be lapp cable (it wasnt), where i measured 80 strands of 0.28mm on which measurements via current confirmed that.
« Last Edit: May 01, 2024, 06:30:22 pm by eTobey »
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Offline eTobeyTopic starter

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Given this glaring lack of scrutiny and total absence of any scientific mindset, I'm 99% sure you just did something wrong.
When two different methods give the same results, then an error is rather unlikely dont you think so?

Also when i do the same error on two different cables, why dont i get the same results on both cables?  ::)

I had another order of cables a few weeks ago, and just went for a shop with a website. I just realised, that they had an ebay account too, and this one was where i got scammed the last time.  :palm:
« Last Edit: May 01, 2024, 06:40:27 pm by eTobey »
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Offline thm_w

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We had a similar discussion here: https://www.eevblog.com/forum/dodgy-technology/is-the-market-flooded-with-fake-dangerous-solar-cable/
You seem to also be buying from random ebay sellers, who are likely just drop-shippers or importers.

If you provide the requested very relevant information up front instead of holding back, its going to make it easier for others to help out:
- Links to the items you purchased
- Advertised diameter and measured diameter
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Offline eTobeyTopic starter

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We had a similar discussion here: https://www.eevblog.com/forum/dodgy-technology/is-the-market-flooded-with-fake-dangerous-solar-cable/
You seem to also be buying from random ebay sellers, who are likely just drop-shippers or importers.

If you provide the requested very relevant information up front instead of holding back, its going to make it easier for others to help out:
- Links to the items you purchased
- Advertised diameter and measured diameter

I have to repeat myself...

It was never my intention to prove anything. I was trying to get the extend of this fraud from other countrys/people too. As your link prooves, its not just something i came across.

Its a really dissapaointing, that most people cant answer a simple question (see original post), and are instead still questioning the findings of others, that are likely not a case of a simple calculation error, as i tried to make clear.
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Offline shapirus

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So I bought a few meters of single-strand cable advertised as 0.75 sq.mm.
Actual measured diameter was between 0.97 mm and 0.98 mm which means 0.739..0.754 sq.mm.

Hope this helps!
 

Offline eTobeyTopic starter

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So I bought a few meters of single-strand cable advertised as 0.75 sq.mm.
Actual measured diameter was between 0.97 mm and 0.98 mm which means 0.739..0.754 sq.mm.

Hope this helps!

I could imagine, that they wont try scamming people on this kind of wire, since it is easy to find out if its scam or not.
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Offline thm_w

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I have to repeat myself...

It was never my intention to prove anything. I was trying to get the extend of this fraud from other countrys/people too. As your link prooves, its not just something i came across.

Its a really dissapaointing, that most people cant answer a simple question (see original post), and are instead still questioning the findings of others, that are likely not a case of a simple calculation error, as i tried to make clear.

What value is it to just post "Yes I was defrauded by cable thickness" without going into any details? Its meaningless data.
Ten people might have bought 1m from one single ebay seller, or one person might have bought 1,000m from hundreds of authorized distributors. The context matters.

Posting the store you purchased from is a normal thing. The fact that you are so secretive with your data and suppliers makes everyone rightfully suspicious.
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Offline eTobeyTopic starter

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Ten people might have bought 1m from one single ebay seller, or one person might have bought 1,000m from hundreds of authorized distributors. The context matters.

Posting the store you purchased from is a normal thing. The fact that you are so secretive with your data and suppliers makes everyone rightfully suspicious.
People can write where they got the cable from. I can not now, as i have not documented my findings. I could get me in trouble. But i might do this on one occasion if i have the mood for it.

This thread is also intented, to raise awareness about this fraud. This can even get dangerous, if cables are not crimped right, because of wrong crosssections.
"Sometimes, after talking with a person, you want to pet a dog, wave at a monkey, and take off your hat to an elephant." (Maxim Gorki)
 

Offline 5U4GB

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    Where were the cables made?   Undersizing of wire and cables made in China has been widely reported on this and other sites.   A lot of the wire is also reported to be made some kind of junk alloy that isn't solderable.  I've learned to not trust the ratings of anything made in China.

Specifically, the most common one you'll encounter is CCA, copper-covered aluminium.  Less common is CCS, copper-covered steel.  Another variant is CCC, copper-covered-copper, where they coat a thin veneer of copper over a garbage alloy of recovered scrap that may contain copper.  They'll look like they're the right size but won't have anywhere near the current-carrying capacity, as well as breaking if you bend them too much when installing them.

Neighbour of mine was happy about the bargain he got on some cabling, until I pointed out what it was that he'd just finished installing...
 

Offline thm_w

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People can write where they got the cable from. I can not now, as i have not documented my findings. I could get me in trouble. But i might do this on one occasion if i have the mood for it.

This thread is also intented, to raise awareness about this fraud. This can even get dangerous, if cables are not crimped right, because of wrong crosssections.

Get in trouble from who and how?
Go grab the cable, measure OD and wire ID and write the info and seller details here, should take 5 minutes.
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Offline f4eru

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and are instead still questioning the findings of others
We always question the findings, whether ours or from others.
Healthy thing to do, especially when the data provided is incomplete.

likely not a case of a simple calculation error, as i tried to make clear.
Nope. You did not make that clear. If you want to make that clear, please provide a simple measurement report/data everybody can check...

No doubt many chinese wires are out of spec.
No doubt also you made some inacuracies in your measurements.
« Last Edit: May 05, 2024, 01:01:07 pm by f4eru »
 

Offline eTobeyTopic starter

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We always question the findings, whether ours or from others.
Healthy thing to do, especially when the data provided is incomplete.

No doubt also you made some inacuracies in your measurements.
There were some inaccuracys, but i questioned and answered my findings until they proved to be right...

You also did not answer my original question...
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Offline eTobeyTopic starter

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New cable order:
From the vendor i had previously bought good cables:
- Measured length. -> 10m
- Has "LEONI P" written on it every 13 cm.
- At 4A and a bit of wiggle, the lowest value of Voltage drop i could achieve was 300mV.
- With my caliber, i measured 0.22mm to 0.23mm (on the most inner side) and up to 0.24mm , when pulling it out.
- After the voltage drop did not speak for a 2.5mm2 cable, i went to the microscope (see picture)
- I counted (2 times) 50 strands. And then again i did that again, and made damn sure, i did not cut/lose any strands.
- Using this https://www.redcrab-software.com/de/Rechner/Elektro/Spannungsverlust it didnt add up.
- The specs on the site of the vendor says: "Leiteraufbau gemäß ISO 6722 (50 x 0,0531mm²)" (Which is 50x0.26mm)

2.5mm2 would be 50 x 0.252mm.
« Last Edit: May 18, 2024, 09:52:57 am by eTobey »
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Offline f4eru

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Now, the correct question is : what does this ISO6722 specify as a minimum tolerance for resistance, and/or section...

Quote
- At 4A and a bit of wiggle, the lowest value of Voltage drop i could achieve was 300mV.
That is a sign that your measurement setup was not good.
Did you solder together all the strands at the entry and exit points?
Did you measure with a good 4-wire setup ?

Offline eTobeyTopic starter

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Now, the correct question is : what does this ISO6722 specify as a minimum tolerance for resistance, and/or section...

Quote
- At 4A and a bit of wiggle, the lowest value of Voltage drop i could achieve was 300mV.
That is a sign that your measurement setup was not good.
Did you solder together all the strands at the entry and exit points?
Did you measure with a good 4-wire setup ?

Of course, it can be done better here, but i do not care in this case, as the other measurement confirmes the data. Not exactly, but id say close enough.

I even went to the effort, to measure a strand visually and turning it 90° to make sure it wouldnt be a eliptic shape. I also looked at more strands, but they are all the same diameter.
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Offline Zero999

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... I ask because measuring cross section of a multi-stranded wire is not trivial at all. Which is also why, to answer your question: I have never checked. I think the risk of me measuring incorrectly would be larger than the manufacturer lying.

Current, voltage drop and ust a few calculations, and then you have the cross section. Nowadays with internet i would call this trivial.

I could not find the very same measurments, but i can give you an example, that is as good. (Scamed by the PCB manufacturer, as he did not mention a tolerance of 20%. Seems to be a chinese thing, yes).
What does that have to do with cables? You also haven't provided any units or how thick the traces are supposed to be.

People can write where they got the cable from. I can not now, as i have not documented my findings. I could get me in trouble. But i might do this on one occasion if i have the mood for it.

This thread is also intented, to raise awareness about this fraud. This can even get dangerous, if cables are not crimped right, because of wrong crosssections.

Get in trouble from who and how?
Go grab the cable, measure OD and wire ID and write the info and seller details here, should take 5 minutes.
Stranded wire is a little more difficult.

You'll need to measure the diameter of each strand, which would require a micrometer, or at least decent calipers, then count the number of strands and perform the calculations to work out the crossectional area or wire gauge.
 

Offline eTobeyTopic starter

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Stranded wire is a little more difficult.

You'll need to measure the diameter of each strand, which would require a micrometer, or at least decent calipers, then count the number of strands and perform the calculations to work out the crossectional area or wire gauge.


Guess what i did....  :palm: :palm: :palm:
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Offline mzzj

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New cable order:
From the vendor i had previously bought good cables:
- Measured length. -> 10m
- Has "LEONI P" written on it every 13 cm.
- At 4A and a bit of wiggle, the lowest value of Voltage drop i could achieve was 300mV.
- With my caliber, i measured 0.22mm to 0.23mm (on the most inner side) and up to 0.24mm , when pulling it out.
- After the voltage drop did not speak for a 2.5mm2 cable, i went to the microscope (see picture)
- I counted (2 times) 50 strands. And then again i did that again, and made damn sure, i did not cut/lose any strands.
- Using this https://www.redcrab-software.com/de/Rechner/Elektro/Spannungsverlust it didnt add up.
- The specs on the site of the vendor says: "Leiteraufbau gemäß ISO 6722 (50 x 0,0531mm²)" (Which is 50x0.26mm)

2.5mm2 would be 50 x 0.252mm.

So you get 7,50 mOhm/meter resistance per your measurement, your online calculator gives theoretical value of 6,9mOhm/m but the actual  IEC 60228 standard for fine-stranded wire is maximum 7,98 mOhm/meter.
I don't see huge issue here as your cable passes the IEC 60228 easily. 
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Offline mzzj

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IEC 60228:
 

Offline eTobeyTopic starter

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I don't see huge issue here as your cable passes the IEC 60228 easily. 

Why should i care about the IEC 60228 standard ?
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Offline thm_w

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ISO6722 https://cdn.standards.iteh.ai/samples/50022/025962355eb24d95b13c98566c51f17e/ISO-6722-1-2011.pdf

2.5mm2
plain copper = 7.6mOhm/m max
tin plated = 7.8mOhm/m max

So it falls within the max no?
Diameter might be off but there are thin and thick versions you'd have to figure out which one it is.
« Last Edit: May 21, 2024, 09:12:39 pm by thm_w »
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Offline Zero999

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I don't see huge issue here as your cable passes the IEC 60228 easily. 

Why should i care about the IEC 60228 standard ?
Why do you care about the thickness, if the resistance is within the limit permitted by the relevant standard?
 

Offline thm_w

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Why do you care about the thickness, if the resistance is within the limit permitted by the relevant standard?

It was sold as ISO6722 so should pass that. It seems to be slightly different from the IEC one.
Anyway, thickness, if you really were using this cable industrially you might care what the insulation thickness was. In this case there are some variations of ISO6722, one of them is ultra thin which allows down to 2.4mm. No idea which one OP bought.

Maybe this is the company? https://www.leoni.com/about-us/quality
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Offline eTobeyTopic starter

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I don't see huge issue here as your cable passes the IEC 60228 easily. 

Why should i care about the IEC 60228 standard ?
Why do you care about the thickness, if the resistance is within the limit permitted by the relevant standard?

I dont care about the thickness, i care about the cross section. It was specified on the product page.

Why are there no dimensions in the standart? As per product details it said its dimensions is from that standard. To me its still a scam, because it says 2.5mm2 everywhere, and not directly that there is a standard for this 2.5mm2 (it should have a '*' and a mention somehwere!
« Last Edit: May 22, 2024, 05:06:32 am by eTobey »
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Offline Zero999

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I don't see huge issue here as your cable passes the IEC 60228 easily. 

Why should i care about the IEC 60228 standard ?
Why do you care about the thickness, if the resistance is within the limit permitted by the relevant standard?

I dont care about the thickness, i care about the cross section. It was specified on the product page.

Why are there no dimensions in the standart? As per product details it said its dimensions is from that standard. To me its still a scam, because it says 2.5mm2 everywhere, and not directly that there is a standard for this 2.5mm2 (it should have a '*' and a mention somehwere!
1) The cross section is determined by the conductor thickness.  :palm:

2) Who cares about the dimensions, so long as it isn't too thick i.e. it fits in the terminals and meets the minimum resistance specification?

3) Would you rather have thicker cables, with the same resistance?

There are different grades of copper. If the manufacturer can use less of a higher grade material, then they can make their cables thinner, whist achieving the same resistance.
 
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Offline eTobeyTopic starter

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1) The cross section is determined by the conductor thickness.  :palm:

2) Who cares about the dimensions, so long as it isn't too thick i.e. it fits in the terminals and meets the minimum resistance specification?

3) Would you rather have thicker cables, with the same resistance?

There are different grades of copper. If the manufacturer can use less of a higher grade material, then they can make their cables thinner, whist achieving the same resistance.

1. Please define "thickness".

2. I do care. Because i dont really care about some standards that tell me "this resistance is good enough for you".

3. Yes, i could live with 2,7mm2 cross section, that has the same restance as a 2.5mm2 (perfect copper) one. Unless it would not be briddle!
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Offline krish2487

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Then I would suggest for your sanity, and more importantly our sanity - get in touch with a cable manufacturer and get the damn thing manufactured to your preferred specifications.
Since you dont care about standards, and most of these run of the mill commercially available stuff is made to some sort of standard ( loose or otherwise )

1) The cross section is determined by the conductor thickness.  :palm:

2) Who cares about the dimensions, so long as it isn't too thick i.e. it fits in the terminals and meets the minimum resistance specification?

3) Would you rather have thicker cables, with the same resistance?

There are different grades of copper. If the manufacturer can use less of a higher grade material, then they can make their cables thinner, whist achieving the same resistance.

1. Please define "thickness".

2. I do care. Because i dont really care about some standards that tell me "this resistance is good enough for you".

3. Yes, i could live with 2,7mm2 cross section, that has the same restance as a 2.5mm2 (perfect copper) one. Unless it would not be briddle!
If god made us in his image,
and we are this stupid
then....
 

Offline Zero999

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1) The cross section is determined by the conductor thickness.  :palm:

2) Who cares about the dimensions, so long as it isn't too thick i.e. it fits in the terminals and meets the minimum resistance specification?

3) Would you rather have thicker cables, with the same resistance?

There are different grades of copper. If the manufacturer can use less of a higher grade material, then they can make their cables thinner, whist achieving the same resistance.

1. Please define "thickness".
There's no point in trying to reason with someone who's too stupid to use a search engine.  :palm: :horse:
 

Offline shapirus

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1) The cross section is determined by the conductor thickness.  :palm:
1. Please define "thickness".
There's no point in trying to reason with someone who's too stupid to use a search engine.  :palm: :horse:
That was a valid question, only not put in a proper way.

Let me reword it:

please provide a formula that defines cross section as function of thickness.
 
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Offline Zero999

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1) The cross section is determined by the conductor thickness.  :palm:
1. Please define "thickness".
There's no point in trying to reason with someone who's too stupid to use a search engine.  :palm: :horse:
That was a valid question, only not put in a proper way.

Let me reword it:

please provide a formula that defines cross section as function of thickness.
It's still basic high school mathematics:

a = πr2

Where:
a = area, which is the cross-section, in this case.
r = the radius.

In this case, the thickness of the conductor, i.e. the diameter, is double the radius, so:

a = π(d/2)2

For stranded wire, the total thickness of the conductor will be a little more because there will be spaces between the strands. One will have to use the above forula for a single strand, then multiply the answer by the number of strands.
 

Offline mtwieg

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"What is thickness" is not an unreasonable question. But "thickness" isn't the standard means of describing conductors. Cross sectional area is (in terms of mm2, kcmil, AWG, etc). Obviously in theory circular conductors have a simple relationship between diameter and area. But copper is ductile and changes shape pretty easily, so any measurements you do with a caliper/micrometer is not going to prove much.

That's not to say that the actual "thickness" of the wire is irrelevant. It matters a lot when it comes to terminating the wire, especially with larger conductors. Recently I found that changing from a "normal" 8awg stranded wire to a fancy 8awg wire with a very high strand count made it impossible to crimp my 8awg terminals. The new wire was certainly 8awg in electrical terms, but not in mechanical terms.
 
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Offline shapirus

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please provide a formula that defines cross section as function of thickness.
It's still basic high school mathematics:

a = πr2

Where:
a = area, which is the cross-section, in this case.
r = the radius.
No no. We weren't talking about radius. That would be too easy. We were talking about thickness.

At least I hope that it was the point of the OP, which he is henceforth invited to elaborate on. Otherwise, I'll be happy to give up.
 

Offline Zero999

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please provide a formula that defines cross section as function of thickness.
It's still basic high school mathematics:

a = πr2

Where:
a = area, which is the cross-section, in this case.
r = the radius.
No no. We weren't talking about radius. That would be too easy. We were talking about thickness.

At least I hope that it was the point of the OP, which he is henceforth invited to elaborate on. Otherwise, I'll be happy to give up.
When it comes to wire, thickness is another term for diameter, which is double the radius.

What's most important is electrical resistance. The standards specify minimum resistances and tolerances for cross-sectional area. If the data sheet states that it meets a certain standard and resistance measurements confirm so, then it meets the standard. It doesn't matter if the diameter/cross-sectional area is slightly less than expected.
 

Offline eTobeyTopic starter

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At least I hope that it was the point of the OP, which he is henceforth invited to elaborate on. Otherwise, I'll be happy to give up.

Of course it was, this is why i used quotes.

I am not a native english speaker, but i would use the term only for "that bunch of strands", but i wouldnt, since this dimension is irrelevant to me.

And why are people searching for standards that would fit, when the dimensions are actually given on the product page? Are you really looking for reasons, so it would be all right that i or others have been scammed? That would be stupid.



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Offline eTobeyTopic starter

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Recently I found that changing from a "normal" 8awg stranded wire to a fancy 8awg wire with a very high strand count made it impossible to crimp my 8awg terminals. The new wire was certainly 8awg in electrical terms, but not in mechanical terms.

You need special terminals for this.
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Offline mzzj

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To me its still a scam, because it says 2.5mm2 everywhere, and not directly that there is a standard for this 2.5mm2 (it should have a '*' and a mention somehwere!
For your mental health I'd suggest for you to stay away from mechanical engineering:
1" pipe that has doesn't match on any dimension to 1"
(american) lumber sizes where 2x4 is like 1.5x3.5"
German 50mm DN50 pipe that has outer diameter excess of 60mm, yet 54mm copper tube is 54mm
And good luck fiquring out if seat belt mounting bolts on your german car are metric or american 7/16" 20 UNF
 
 
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Offline eTobeyTopic starter

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(american) lumber sizes where 2x4 is like 1.5x3.5"

German 50mm DN50 pipe that has outer diameter excess of 60mm, yet 54mm copper tube is 54mm

Go ask those americans, why that is!

Compared to electrics you would measure the conductor diameter with the insulation? Not really smart id say.
"Sometimes, after talking with a person, you want to pet a dog, wave at a monkey, and take off your hat to an elephant." (Maxim Gorki)
 

Online TimFox

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(american) lumber sizes where 2x4 is like 1.5x3.5"

German 50mm DN50 pipe that has outer diameter excess of 60mm, yet 54mm copper tube is 54mm

Go ask those americans, why that is!

Compared to electrics you would measure the conductor diameter with the insulation? Not really smart id say.

In America (and other places) pipes are sized by inner diameter, but tubing is sized by outer diameter.
Outside of America, I believe many pipe sizes are derived from inch measurements.
 

Offline eTobeyTopic starter

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(american) lumber sizes where 2x4 is like 1.5x3.5"

German 50mm DN50 pipe that has outer diameter excess of 60mm, yet 54mm copper tube is 54mm

Go ask those americans, why that is!

Compared to electrics you would measure the conductor diameter with the insulation? Not really smart id say.

In America (and other places) pipes are sized by inner diameter, but tubing is sized by outer diameter.
Outside of America, I believe many pipe sizes are derived from inch measurements.
My first sentence was intented for the first sentence of the quote. I think i have to do this different the next time?
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Offline thm_w

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And why are people searching for standards that would fit, when the dimensions are actually given on the product page? Are you really looking for reasons, so it would be all right that i or others have been scammed? That would be stupid.

Its not "standards that would fit" its literally the standard that the wire was produced to meet. A dimension without a defined tolerance is near meaningless in engineering.

Anyway, can you just link the supplier in question?
I found this one https://www.autoteile-plauen.de/artikel-1724.htm which says OD is 2.7 to 3mm, so you could tell them it doesn't meet that spec if you want (assuming that is the supplier).
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Online TimFox

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(american) lumber sizes where 2x4 is like 1.5x3.5"

German 50mm DN50 pipe that has outer diameter excess of 60mm, yet 54mm copper tube is 54mm

Go ask those americans, why that is!

Compared to electrics you would measure the conductor diameter with the insulation? Not really smart id say.

In America (and other places) pipes are sized by inner diameter, but tubing is sized by outer diameter.
Outside of America, I believe many pipe sizes are derived from inch measurements.
My first sentence was intented for the first sentence of the quote. I think i have to do this different the next time?

The syntax on quoting and replying can be tricky.
Hint:  if you hit the "preview" button, you can see what will post before you hit "post".
As posted, you replied to two sentences excerpted from the earlier MZZJ post with one sentence, and I replied to what was posted to clarify the part about the difference between pipe and tubing dimensions.
 

Online themadhippy

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Quote
(american) lumber sizes where 2x4 is like 1.5x3.5
2x4 is the rough cut size,  1.5x3.5 is what you end up with once its been finished  smooth with all those annoying splinters removed
 

Offline ejeffrey

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Quote
(american) lumber sizes where 2x4 is like 1.5x3.5
2x4 is the rough cut size,  1.5x3.5 is what you end up with once its been finished  smooth with all those annoying splinters removed

Sort of.  It used to be about 2x4 rough off the sawmill, then it shrinks as it dries and is then milled down for smoother surfaces.  In the old days, 2x4s were larger than today, but varied in size depending on the type of wood, moisture content, and how aggressively they are milled.

But as construction became more standardized and drywall became common, people wanted uniform size, so the 2x4 rough that ended up typically around 3.625x1.625 or so was redefined to the slightly smaller 3.5x1.5 finished size, with the rough cut size whatever is needed to meet that.

Which is just a tangent but a good example of how nominal sizes and size classes need to be interpreted carefully and need to actually check the relevant standards.
« Last Edit: May 23, 2024, 03:04:21 am by ejeffrey »
 


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