 Just a bitch that we have dealt with before:

 Phil please realize that 207.846096....... is meaningless except that it is
 "about 208". 208V is correct to 3 significant figures which is actually
 better than one can assume to be true in practice. If the voltage line to
 neutral is actually 120.V (note the decimal) then we have 3 significant
 digits implying something between 119.5 Vand 120.5.V
 Then all you can truly claim is 208.V
 If it is 120.0V then there is reason to assume 208.0 V but no more decimals
 than that.
 If you have a meter which gives you 120.000000V with less than 1 part in 120
 million error then you can claim 207.846097V for line to line voltage Do
 you have such a meter?

 Engineering and physics students who ignore the principle of "significant
 digits" lose marks for this "decimal inflation".

 Sure you can let the calculator carry the extra digits (as it will do
 internally) but accepting these as gospel truth to the limit of the
 calculator or computer display is simply not on as you can't get better
 accuracy from a calculation than the accuracy of the original data (actually
 you will lose a bit). All that you get rid of is round off errors in
 calculations.

 Since, as you say, precise voltage is not really practical, then
 multidecimal point numbers are meaningless. If we say 120V +/10% then we
 are talking about 108132V which for line to line becomes 187229V (average
 208V) and any extra decimal points don't mean anything.
You didn't notice the :) I put on the number?
We've been over this. I know the practice of significant digits, and how the voltages are designated (two different reasons you can get 208). I do follow the practice of carrying exactly the result of calculations into other calculations. I also use over significance in comparison of numbers.
But I also know that rounding is a form of noise. So I avoid it until the time I end up with the final result. So if I multiply 120 by the square root of three I do get a number like 207.84609690826527522329356 which is either carried asis into the next calculation, or rounded if it is the final answer. If some other strange calculation happens to give me the value 207.84609690826527522329356 then I know it is effectively equivalent to 120 times the square root of three in some way. But if what I get is 208.455732193971783228 then I know it has nothing to do with 120 times the square root of three, even though it, too, would end up as 208 if rounded to 3 significant digits.
When it comes to _measured_ amounts, as opposed to synthetic ones, then the significance rules dictate how to round the results. With synthetic numbers (e.g. numbers I can just pick), I can also pick the rounding rules for the final results. But if I don't know that the calculations are done (e.g. I am not merely giving a designation for a voltage system), where someone else may take those numbers and do more calculations and round the results, then I do use more significance. But that is no different to me than just carrying that number from one calculation stage to another.
You didn't notice the :) I put on the number?
We've been over this. I know the practice of significant digits, and how the voltages are designated (two different reasons you can get 208). I do follow the practice of carrying exactly the result of calculations into other calculations. I also use over significance in comparison of numbers.
But I also know that rounding is a form of noise. So I avoid it until the time I end up with the final result. So if I multiply 120 by the square root of three I do get a number like 207.84609690826527522329356 which is either carried asis into the next calculation, or rounded if it is the final answer. If some other strange calculation happens to give me the value 207.84609690826527522329356 then I know it is effectively equivalent to 120 times the square root of three in some way. But if what I get is 208.455732193971783228 then I know it has nothing to do with 120 times the square root of three, even though it, too, would end up as 208 if rounded to 3 significant digits.
When it comes to _measured_ amounts, as opposed to synthetic ones, then the significance rules dictate how to round the results. With synthetic numbers (e.g. numbers I can just pick), I can also pick the rounding rules for the final results. But if I don't know that the calculations are done (e.g. I am not merely giving a designation for a voltage system), where someone else may take those numbers and do more calculations and round the results, then I do use more significance. But that is no different to me than just carrying that number from one calculation stage to another.

WARNING: Due to extreme spam, googlegroups.com is blocked. Due to ignorance 
 by the abuse department, bellsouth.net is blocked. If you post to 
WARNING: Due to extreme spam, googlegroups.com is blocked. Due to ignorance 
 by the abuse department, bellsouth.net is blocked. If you post to 
Click to see the full signature.