Voltage drop calculations

[alixenos]

Hello,

I'm new to this, but in an electrical network, when do we decide that we need to check for voltage drop and do our calcs per the NEC code?

I'm following my senior engineer, but I don't understand when he decides to do those calcs for a specific path in a given electrical network.

Thank you

 

[augie47]

If you look at only the NEC there are only a few places where it is required that voltage drop be taken into account. Fire Pumps (Art 695) and Sensitive Electronic Equipment (Artb 647) for example.
Art 210.19 referenced VD but only as a non-required informational note.
More recent energy codes now require voltage drop to be considered on additional circuits,.

 

[drktmplr12]

1. when the distance is far enough
2. when the amps are high enough

 

[retirede]

1. when the distance is far enough
2. when the amps are high enough

And after some years of experience, you have a pretty good idea of when a calculation becomes warranted.

 

[don_resqcapt19]

A rule of thumb that an engineer taught me is that when the one way length of the circuit in feet starts to approach the circuit voltage, you need to take a look at possible voltage drop issues.

 

[texie]

I seem to recall that Florida had requirements for VD along the lines of the NEC "recommendation".