Ribbon Cable - What is the max current?

Go To Last Post
9 posts / 0 new
Author
Message
#1
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Hi folks,

I've got some ribbon cable I'd like to use to jump from one board to another. The total length should be about 3 inches and I'm looking to put 5v through at a maximum of .5A on one wire at a time.

The cable that I have is 28awg and the following stamped on it:

Quote:
Don Connex E162690 RU AWM2651 300V 105C VW-1 RoHS 0919

The R in "RU" is backwards that the 105C has a degrees symbol between the 105 and the C.

How can I tell if the current (or power) is too much for this cable?

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Ribboncables are not meant to be used for this. But if you want to use it: Try it !!
28awg will handle .5A I think. But 20 amps through a 40 ribbon ?? No way.

A GIF is worth a thousend words   They are called Rosa, Sylvia, Tessa and Tina, You can find them https://www.linuxmint.com/

Dragon broken ? http://aplomb.nl/TechStuff/Dragon/Dragon.html for how-to-fix tips

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

100ma per pin

Imagecraft compiler user

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

barney_1 wrote:
Ribbon Cable - What is the max current?

Who makes the ribbon cable? What does the data-sheet say?

The last I looked, even ribbon cable has a data-sheet.

Quote:
Don Connex E162690 RU AWM2651 300V 105C VW-1 RoHS 0919

I've linked to the data-sheet.
http://www.donnex.com.tw/php/show.php?category=l01

All I did was do a Google search on the key word "Don Connex ." Low & behold, the very first hit was a home run. Simply selecting "Ribbon Cables " from the pull down menu, brought up the model number - the very first in the list.

barney_1 wrote:
I'm looking to put 5v through at a maximum of .5A on one wire at a time.

Now, I didn't see a maximum current specification in the data-sheet.

But wait a minute...

Googling on the key word "Wire Current " brought up the very first hit "American Wire Gauge table and AWG Electrical Current Load Limits ."

Clicking on that like brought up http://www.powerstream.com/Wire_Size.htm

And look at what I found...

About half way down the web-page:

AWG = 28
Diameter = 0.0126"
Ohms/1000 ft = 64.9
Ohms/km = 212.872
Maximum Amperes for chassis wiring = 1.4
Maximum Amperes for power transmission = 0.226
Maximum frequency = 170 kHz

As this is a short run, "Free Air " situation, you could use the "Max Amps for chassis wiring = 1.4 " and derate that value by some percentage at the expected ambient operating temperature.

So, even a 50% derating will allow for 0.7 Amperes per wire in the ribbon cable - which is still probably very conservative.

So next time... Let your fingers do the Googling, driven by a small amount of Creative Thinking. This way, I won't have to spend another 20 minutes researching copying, pasting, and explaining one of the most basic tools on the embedded micro-controller field.

"Feed a man a fish, and you feed him for today. Teach a man to fish, and you feed him for life !"

You can avoid reality, for a while.  But you can't avoid the consequences of reality! - C.W. Livingston

Last Edited: Thu. May 22, 2008 - 10:10 PM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

and if you want to be on a safe side, use multiple lines for both Vcc and GND. less current per wire that way.

EDIT: added multiple to the sentence...

Last Edited: Thu. May 22, 2008 - 11:25 PM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

bloody-orc wrote:
and if you want to be on a safe side, use lines for both Vcc and GND. less current per wire that way.

You might have meant "...to be on a safe side, use multiple lines for both Vcc and GND. "

I.E. use two or three lines for VCC and two or three lines for GND.

You can avoid reality, for a while.  But you can't avoid the consequences of reality! - C.W. Livingston

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

:oops: oh yes. sry about that... somehow that word disappeared after multiple rewrites of that sentence...

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Thanks folks. I appreciate your research time Carl, as well as the explaination!

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

The next question is 'how much current can you pass through an IDC connector'? Probably around 100mA as Bob suggests. I haven't seen any hard evidence nor have I looked too hard but experience has taught me not too pull too much as the contact area is quite small. As the others have suggested, use a few conductors in parallel.