Author Topic: 4 out of 5 vendors are scamming people with wrong crosssection of cables  (Read 6594 times)

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Online 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:
 

Online 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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Online 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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Online 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.
 

Online 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.



"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 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.
"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 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)
 

Offline 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?
"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 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).
Profile -> Modify profile -> Look and Layout ->  Don't show users' signatures
 

Offline 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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