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Topic: Checking continuity on cords: Shouldn't it show zero? |
George Kimery
From:
Limestone, TN, USA
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Posted 6 Oct 2014 2:33 pm |
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I had a cord that was not working, so I pulled out my multi-tester and set it for continuity to run down the problem. I noticed that as I checked several cables, the sleeve (neutral) all checked to zero on the meter's read out. However, only one 12 inch cord checked to zero on the tips. All the other cords showed readings.
Here was the result:
12 ft. cord .002
3 ft. cord .006
12 ft. cord .040
1 ft. cord .004
3 ft. cord .004
1 ft. cord Zero on tip and sleeve
The cords and plugs are George L. Am I just not getting a good connection on the hot tip? Or are these numbers so insignificant that it does not matter? The cords all work. Although I have used the George L plugs for years, I still think that they are inferior to a Switch Craft, solder connected plug. If I have a problem that matters, I am ready to throw in the towel on the George L plugs. I like the cables, but not the plugs. |
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Scott Duckworth
From:
Etowah, TN Western Foothills of the Smokies
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Posted 6 Oct 2014 5:57 pm
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Were your fingers touching the probes or cable? You could be reading your body resistance. If you lick your fingers and grab the probes, the resistance changes.
_________________
Amateur Radio Operator NA4IT (Extra)
http://www.qsl.net/na4it
I may, in fact, be nuts. However, I am screwed onto the right bolt... Jesus! |
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Steve Collins
From:
Alaska, USA
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Posted 6 Oct 2014 8:19 pm
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| Those are really low numbers in terms of resistance, low enough to be considered insignificant. |
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Dave Mudgett
From:
Central Pennsylvania and Gallatin, Tennessee
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Posted 7 Oct 2014 5:14 am
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Are those Ohms? Do you expect wire to have zero resistance?
Here's a table of copper wire resistance by wire gauge - http://en.wikipedia.org/wiki/American_wire_gauge
Just as an example, 16 gauge copper wire has a resistance of about 4 mΩ/ft, or 0.004 Ω/ft. So a 10-foot 16 gauge cable without other additional series impedance (e.g., due to other connections) has a DC resistance of about 0.04 Ω. Cable resistance definitely can vary based on wire gauge, wire material, and other variables. |
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Paul Arntson
From:
Washington, USA
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Posted 7 Oct 2014 7:10 am
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Also, when you get down in those very low ranges, I would expect to see a few milliohms (0.001 ohm) just from the connection where the meter probes touch.
_________________
Excel D10 8&4, Supro 8, Regal resonator, Peavey Powerslide, homemade lap 12(a work in progress) |
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George Kimery
From:
Limestone, TN, USA
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Posted 7 Oct 2014 1:44 pm Checking continuity on cords: Shouldn't it be zero?
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Scott, I was not touching the ends or the probes, so I was not reading body resistance.
David, I was just using the selection switch on my multi tester set for continuity. When you have continuity there is a little beeper sound. It was not measuring OHMS. Also, I don't know enough about wire resistance, so your comment about me expecting it to read zero was a bit beyond my knowledge. I have just always assumed that if a cord is working properly and you check the continuity, it would be zero, otherwise you have a problem. My ignorance on the subject.
I am just going to rely on the old adage "If it's not broken, don't fix it" The cords work fine, so that is what is important. |
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