2002-12-25 Brenton,
When you say 2.5 mm power cable are you describing the wire diameter or the cross sectional area of the wire? In the case of the cross sectional area that would be 2.5 mm�. Wire in metric countries is sized in square millimetres. 2.5 mm� is one of the standard sizes. I'm just wondering if in common practice, the � is dropped from the unit. I wish I could remember the IEC standard designating the standard sizes. John ----- Original Message ----- From: "Brenton" <[EMAIL PROTECTED]> To: "U.S. Metric Association" <[EMAIL PROTECTED]> Sent: Wednesday, 2002-12-25 21:13 Subject: [USMA:24242] Re: Millimetres, centimetres, and decimetres > I am from the building Industry (Electrician) > > I was taught to work solely in mm, not cms. For example, the average office > ceiling height was 2600. A recessed fluorescent light fitting would replace > a ceiling tile of 1200 x 600. > > Cable however was always measured in metres, i.e. a 500-metre drum of 2.5mm > power cable, or similar. I have only come across mm represented as m > (1.200m or 0.600m) or cm (120 cm or 60 cm) outside the building industry. I > never saw a representation of metres as 1.20.0. > > Season Greetings > Brenton Conway > Adelaide - Australia. > > > > > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of > Pat Naughtin > Sent: Thursday, 26 December 2002 12:27 > To: U.S. Metric Association > Subject: [USMA:24241] Re: Millimetres, centimetres, and decimetres > > Dear Mike, > > Thanks for this. It reminds me of a story* I heard in the seventies about a > some builders in France. They had been brought up building with metres and > centimetres and they separated them with a decimal marker (a comma or > virgule in their case). When they needed greater precision say for an > architrave they simply popped in another decimal marker. > > Using your example of 1234 mm, this would become 1,23,4 for the builders in > France. In Australia, this would be 1.23.4, and it would be read as 1 metre > 23 centimetres and 4 millimetres. > > I still admire the judgement of the Australian Metric Conversion Board, who > made the decision to use millimetres only. > > * I believe that this story came from the the consultative process that > went on before the Construction Industry Committee made their decision on > which units to use for construction in Australia. > > Cheers, > > Pat Naughtin LCAMS > Geelong, Australia > > on 2002-12-25 17.16, Mike Joy at [EMAIL PROTECTED] wrote: > > > Pat wrote:- > > > > The Australian experience is that metric transition can be done in less > > than > > a year if you use millimetres and in about fifty years if you use > > centimetres. > > > > ***************** > > > > So true, Pat. I watched some builders build my extension 5 months ago, two > > extra storeys on our house, and saw how easy it was for them to measure > > lengths of wood, etc, and cut them accurately every time to the nearest > mm. > > > > They were working from plans 1:100 and had no problem with that. No > > mistakes at all. > > > > There's no question that it's easier to measure and cut a length of wood, > > say, 1234 mm long as it's easier to remember than 'one two three POINT > > four' cm long, and then try and work that out on your tape which is in mm > > anyway. Bound to lead to errors and hence wastage. > > > > Another main reason mm is used is because it's easier to have two units to > > work with than three, i.e.. mm and m, rather than mm, cm and m. > > > > Costings were accurate as calculations were done in mm and then rounded up > > as necessary. > > > > Folk who insist on using centimeters and Centigrade are usually those who > > live in the past and are not the practical type. > > > > Regards > > > > Mike > > Perth, Australia > > > >
