Another Voltage Drop Question...

[cyriousn]

Hello I've been reading so many different threads on this and I just want to make sure I have this correct.

I'm using the Effective Z values from Chapter 9 Table 9.

As an example I have a 600KCMIL feeder which reads at 0.047 effective Z for copper conductors in EMT for the 0.85pf.

I'm the following forumula: 1.732 * Length * Effective Z * Current / 1000

1.732 * 640ft * 0.047 * 2000A / 1000= 104.2 volts.

If we have 5 sets I divide by 5 and get 20.84v total for a 4.3% voltage drop on a 480V system.

Just trying to sanity check myself here. Thanks in advance.

 

[xptpcrewx]

This looks correct to me. Note: Your result is at 75 deg C.

I use a different method, but if you want a conservative figure with worst-case power factor, I wouldn't go past 385 ft. at 2000 amperes (3% Vx @ 30 deg C).