Style guide opinions: Space between value and units

[Tomorokoshi]

I'm working on some technical documents, and it's bringing up the subject of consistency when writing values with units. The key is whether or not to use the space between the value and the units.

For example:
V = 10V
I = 100mA
T = 50ºC

as opposed to:
V = 10 V
I = 100 mA
T = 50 ºC

I've seen both styles within the same technical document, and I admit I've used both as well. There are guides for this:

http://physics.nist.gov/cuu/Units/rules.html

http://physics.nist.gov/cuu/pdf/sp811.pdf
See section 7.2.

One of the issues I have is that many common devices show this information without the space. I am now leaning to using the space as described in the style guide.

Are there any strong arguments to not use the space?

[T3sl4co1l]

Yes, absolutely.

On forums, I sometimes do either, partly out of laziness, and partly out of limitations of the medium.  For technical writing, the space is indeed the correct, and better looking, way to do.

Note that it needs to be a non-breaking thin space.  In Unicode, this either uses a normal thin space (I don't remember if it is breaking or not), or non-breaking 'glue' zero-width-spaces to hold it together.  In HTML, you might also put it in a non-breaking <span>.

In \$\LaTeX\$, I use a macro which puts the expression in math mode, with the unit in \textrm{} so it looks right and doesn't break.  (Math mode isn't necessary for writing out simple numbers, but makes it easier to write short expressions, and units with odd powers or ratios).

Tim