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Current/Voltage rating on power cord

  1. Apr 24, 2006 #1
    I have 2 identical scanners that have 2 different power cords. One of them is 3A/125V and the other is 7A/125V. My question is, does the difference in amps matter that much. Could someone explain this to me in detail?
  2. jcsd
  3. Apr 24, 2006 #2


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    Staff: Mentor

    The current rating is based on how warm the cord will get while passing that current. There is probably some UL standard that sets the delta-T allowed at max rated current. So your 7A power cord will use a larger wire (lower wire gage number) compared to the 3A cord. I don't know if the length of the cord is involved in the current rating also -- probably not.

    The voltage rating has more to do with the insulation properties and spacings used in the construction.
  4. Apr 24, 2006 #3


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    When you said, scanner the first thing that came to mind is a radio receiver that scans across a band of frequencies. ref1 .

    Another kind of scanner is an input device on a computer (scans image and displays on computer). ref2

    Either way, just to expand on what berkeman described, the values you described is the current handling capacity for that cord. The scanner with cord rated 7A/125V can and probably will draw more current than the one that uses 3A/125V. If you draw more current than the cord rating, the insulation can melt, potentially cause a fire, and is dangerous to you and any curious pets who touch the cord (that is crackling and making sparks) :surprised

    So yes the difference in amps does matter.
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