Note on history of E-I-R tables format

Discussion in 'Feedback and Suggestions' started by rogerk, Jul 2, 2011.

  1. rogerk

    Thread Starter New Member

    Jul 2, 2011
    Took electrical-code class in 1999 in Florida taught by local inspector [chief] Jack Leahy. I recall his wife earlier originated the P[power]-E-I-R table used in his classes. P-E-I-R very handy. Thanks to all who contributed to AllAboutCircuits...also very helpful.
  2. Adjuster

    Well-Known Member

    Dec 26, 2010
    Note on history of E-I-R tables format? That's intriguing, but many readers will only be able to guess what an E-I-R table was.

    Perhaps it was a handy lookup table for doing Ohm's law calculations, the sort of "ready reckoner" that was more common back in the days before we had so many computers and portable calculators?

    Or was it a more general reminder of useful information, maybe including some details of wiring codes and electrical regulations, or such things as wire tables, screw threads and drill sizes, formulae and constants?

    It would be interesting to know...
  3. Wendy


    Mar 24, 2008
    Another name for E-I-R, Ohm's Law. I always liked the pyramid myself.

    Welcome to AAC.

    Not sure if this was the right forum for this, but the mods will figure it out. It is borderline.
  4. #12


    Nov 30, 2010
    Interesting. I learned about the WIRE wheel in 1968. W for watts, I for current, R for resistance, and E for electromotive force (voltage). This makes me think the idea was originated before 1999.
  5. Wendy


    Mar 24, 2008
    I suspect so, most serious electronic concepts of that nature were pretty developed in the 30's. Time for Google.