I have been told by someone that the use of a capital "C" in calories denotes that it is 1000 calories. So writing 0.3 Cal/cm2 means 300 calories/cm2. As anyone heard of this as I thought the prefix for kilo, "k", would be needed to designate 1000?

The "k" prefix would be required to designate 1000

The physical unit is calorie (small letter C)
The dietary/nutritional unit is often called Calorie (large letter C). The dietary word is actually kilocalorie or 1000 calories, but you know how people hate using technical language.

The recommended SI unit is calorie (lower case), with the abbreviation cal (lower case). Abbreviations of SI units named after people are capitalized (A for ampere, K for Kelvin, etc.) but other are not.

When we geezers were educated, (I'm 57) capital "C" (Calories) was used for Kcal for food but small "C" (calories) is for the SI unit.

This is NOT true outside of the US since SI units were standardized.

LOL.

Hugh Hoagland


I'm still trying to keep NFPA 70E from using mm for working distances since in SI the unit indicates the level of accuracy needed in the measurement.

Good info everyone. A few additions. I attached an E.U. label. They even show kilo-Joules of energy in addition to kilo-calories. FYI for all, a Joule of energy is a watt-second. Good luck with the “diet math� The good news, regarding any live working and PPE standards for the IEC, calories (lower case c) is all we need.

Global standardization is still evolving. There was a similar problem years ago with conductor sizes and some people still get tripped up. As an example, 500 MCM was commonly used. cm is the unit of measure in circular mils which we still use but “M� was a throwback to using roman numerals where M = 1000. Finally, this was changed to “k� for kilo and now we have kcm or 500 kcm which is easier to relate to. Although we adapted to “k�, cm isn’t widely used globally.

The working distance has been listed as mm in IEEE 1584 since it was published in 2002 and is a bit awkward. However, there is a column for inches as well. cm – centimeters, not to be confused with cm - circular mils would be much better. The next edition of IEEE 1584 which is rapidly nearing completion also has mm and inches.

Hugh, I hope we both have a ways to go before “geezerdom�. I have a couple of years on you but so many people within IEEE, IEC etc. are well into their mid and late 60’s and 70’s (a few pushing 80) so for now I will hang on to my “youth�. ...although I mentioned a french curve in a class a couple of years ago and got a blank stare by about 2/3 of the group. The older I get, the more my definition of “old� keeps changing.

I've always seen it as either MCM or kcmil, never kcm so kcm in my mind would be some bastard unit...meters x 1000 / 100 = decameters of cable? Never seen it as kcm anywhere I can think of.