Voltage Drop and Power Factor

[thomrk]

When do you include power factor when calculating voltage drop for a branch circuit conductor? The voltage drop calculator that I use doesn't even have a place for power factor, so I was wondering if you assume the power factor to be 1.0 when just looking at the conductor itself.

 

[skeshesh]

I do and have not seen others consider power factor for branch circuit VDs. It may be worth while if you need to be very accurate for feeders, but again I usually don't. If using a calculator that does not account for PF you can introduce it using the I value: I(rms) = P(VA)*P.F. / V(rms) and then input that value into the calculator instead if I = VA / V value as often used in producing panel schedules.

 

[iceworm]

When do you include power factor when calculating voltage drop for a branch circuit conductor? The voltage drop calculator that I use doesn't even have a place for power factor, so I was wondering if you assume the power factor to be 1.0 when just looking at the conductor itself.

Consider 3ph highly inductive loads. An example is starting an electric fire pump motor and keeping the vd to 15%. I tend to use table 9. Be sure to read the table notes.

This will require that you use math - not a plug-in-the-numbers calculator.

However, if all your branch circuits are 120V residential-like then I would likely ignore pf as already suggested

ice

 

[thomrk]

Thanks for the info. This is just for a exterior light string in a parking lot.