Spaces between numbers and units

Question

Ok, so I write this beautiful answer ;-), and then comes this hooligan insert spaces between all my numbers and units. 600V is not "600V", it's "600 V". I've seen edits like that before, but I wonder if that's necessary. Yes, I'm aware of ISO-31, but do we give a damn? I've posted 1115 answers so far and nobody ever complained that he couldn't read "600V". I think it's unnecessary, and it only bumps the question.
What do others think?

edit
Just posted an answer nicely inserting the spaces when I hit upon a problem. I write "4/20 MHz" and it looks like "(4/20) MHz" (200 kHz)or , while I mean "4/(20 MHz)", (200 ns). How do you read "4/20 MHz"?

Answer 1

As for your example, it was already fairly near the top, and the reason for the edit was primarily to remove dozens of single-character MathJax calls. They look ugly (they're italicized by default which clashes with the rest of the text), and are are slow.

More to your question, 600V isn't that bad, but 1µA, 1MΩ are worse. I'm not liable to bump a question to fix one or two, but if I stumble across a question which has several formatting issues, it's likely. Deciding whether or not to edit a post involves many factors, chief among which is the do-I-feel-like-it factor.

If you're asking my opinion about how posts should be written ("if I was king"), there should be a space between numbers and units as per the standard you site as well as NIST (see #10 on the checklist, or below) and SI. If it's in reference to some sort of nominal value (a 12-V car battery, 5-V logic), I think there is some other method for that but I am not sure.

NIST Special Publication 811 2008 Edition

Guide for the Use of the International System of Units (SI)

7 Rules and Style Conventions for Expressing Values of Quantities

7.2 Space between numerical value and unit symbol

In the expression for the value of a quantity, the unit symbol is placed after the numerical value and a space is left between the numerical value and the unit symbol.

The only exceptions to this rule are for the unit symbols for degree, minute, and second for plane angle: °, ', and ", respectively (see Table 6), in which case no space is left between the numerical value and the unit symbol.

Example: α = 30°22'8"

Note: α is a quantity symbol for plane angle.

This rule means that:

1. The symbol °C for the degree Celsius is preceded by a space when one expresses the values of Celsius temperatures.
   • Example: t = 30.2 °C but not: t = 30.2°C or t = 30.2° C
2. Even when the value of a quantity is used as an adjective, a space is left between the numerical value and the unit symbol. (This rule recognizes that unit symbols are not like ordinary words or abbreviations but are mathematical entities, and that the value of a quantity should be expressed in a way that is as independent of language as possible—sees Secs. 7.6 and 7.10.3.)
   • Examples:
     • a 1 m end gauge but not: a 1-m end gauge
     • a 10 kΩ resistor but not: a 10-kΩ resistor

However, if there is any ambiguity, the words should be rearranged accordingly. For example, the statement “the samples were placed in 22 mL vials” should be replaced with the statement “the samples were placed in vials of volume 22 mL.”

Note: When unit names are spelled out, the normal rules of English apply. Thus, for example, “a roll of 35-millimeter film” is acceptable (see Sec. 7.6, note 3).

Answer 2

I see nothing wrong with any edit, and more than being pedantic about standards, I really feel the space improves readability.

It has been discussed that a checkbox like "This is a minor edit" might be helpful for such smallish cleanups - if you don't like the question to reappear at the top of the list.

Just one note: I would enjoy spaces to be edited into my answers, but (outside MathJax) please with a non-breaking space (" ") instead of a plain space (" "), because a line break between the number and the unit certainly doesn't improve readability.

Related: https://electronics.meta.stackexchange.com/a/621/930

Answer 3

I would consider an edit to place a space between 600 and V a very minor edit. I would consider it too superficial an edit to be worth doing if that is all someone is editing. I would suggest against it but I am not sure someone trying to improve a post, which was technically done here, is something they can feel free to do.

Just suggest to users whom you see do this that they try to save edits for more egregious errors. This is not something that is in itself an issue when done occasionally. This is only a real issue if the edits are flooding the main page with edits.

Do try to remember, this is someone taking their time to try to improve the look of your post. You should take it as them considering your post so valuable that polishing up these minor things are worth it. No one would do that for a poorly explained post. Take this as a compliment, not as someone voting down your post(wait, not a vote down).

Answer 4

I totally agree - it is unnecessary. I have just had a look through 20 - 30 datasheets from 12 manufacturers and in the majority of cases, they don't put spaces between numbers and units.

The results of my (highly unscientific) "statistical analysis" show that whilst Bourns consistently uses spaces, Microchip uses spaces around 50% of the time and most others use spaces from zero to around 20% of the time - in the same datasheet!. I would also note that I had never even noticed this before in 30 years in the industry.

So I would suggest that we all have to be able to read values written without spaces ... and one users idea of improving the look of a post will not necessarily extend to all users.

Note to steven - You recently changed the spelling of "modelling" in one of my answers to "modeling". Since I speak EN-GB and not EN-US, I seriously considered changing it back!. In the end I re-worded the entire answer anyway. Just sayin' ;)