Voltage drop on a.c. circuits

[CONDUIT]

I see that almost all voltage drop examples are based on chapter nine table eight. I have worked some using chapter nine table nine and most of the time they don't come out to far apart.
Just curious as when it would be critical to know the exact impedance including inductive and capacitant reactance to calculate the voltage drop. Also was wondering if anyone had a example of when table eight wouldn't be accurate enough.

 

[Hv&Lv]

I see that almost all voltage drop examples are based on chapter nine table eight. I have worked some using chapter nine table nine and most of the time they don't come out to far apart.
Just curious as when it would be critical to know the exact impedance including inductive and capacitant reactance to calculate the voltage drop. Also was wondering if anyone had a example of when table eight wouldn't be accurate enough.

Here is an article showing using Q and K constants in the VD formula. This uses the difference in tables 8&9
http://ecmweb.com/content/calculating-voltage-drop-power-distribution-systems

 

[GoldDigger]

I see that almost all voltage drop examples are based on chapter nine table eight. I have worked some using chapter nine table nine and most of the time they don't come out to far apart.
Just curious as when it would be critical to know the exact impedance including inductive and capacitant reactance to calculate the voltage drop. Also was wondering if anyone had a example of when table eight wouldn't be accurate enough.

Please take a look at this thread for a lot more on the subject, if you are interested in the technical background.

 

[ZZDoug]

when it would be critical to know the exact impedance including inductive and capacitant reactance to calculate the voltage drop

It's always been my understanding that there is very little difference until you start dealing with large current flows (which starts causing significant inductance). And in the real world we don't normally have really large current flows on particular wire/coduit because we parallel stuff. However lots of parallel runs and also long distances can multiply the different table values so in these cases I try to use Table 9.