International System of Units rules

[renzodelfabbro]

Just a question about the use of the right
S.I. rules and style conventions in the
English Technical Writing.
Why I always see (and in this forum too):
volts ohms meters
and not
volt ohm meter ?
Thanks,
Renzo Del Fabbro

 

[jghrist]

I thought that you added an "s" when pluralizing the name of a unit but not the symbol of a unit.

10 volts 25 ohms 239 meters
10 V 25 &[ignore]Omega;[/ignore] 239 m

 

[renzodelfabbro]

First I was wrong including meter in my question.

Second I see also NIST let the use of plural for
volt ampere and ohm

http://physics.nist.gov/Pubs/SP811/sec06.html

Third 10 V is correct not 10 volts

 

[jghrist]

Your reference pertains to the plural of symbols not the written out units. It does not address plurals of written out units because the NIST says the "values of quantities should be expressed in acceptable units using ... the symbols for the units, not the spelled-out names of the units." per Section 7 of the guide. According to this, neither 10 volt nor 10 volts is correct.

 

[jbartos]

Suggestion: Reference:
ANSI/IEEE Std 945-1984 IEEE Recommended Practice for Preferred Metric Units for Use in Electrical and Electronic Science and Technology

Item SI Symbol (Unit)
6.6 V (volt)
3.4 m (meter)
6.26 &[ignore]Omega;[/ignore] (ohm)

The unit can be singular (volt) or plural (volts). E.g. 1 volt, 2 volts, expresion in volts, volt/meter or V/m for Electrical Field Intesity etc. The singular versus plural is to be applied according to the English grammar.