Hey electricians...

Friend of mine just had 400 AMP 3 phase put in his shop. It's 208 volts. He
has a machine that says 230 Volts on the name plate. The machine has an
autoformer in it for 208 or 230 volts. (The machine is actually 400 volts,
it's from Italy, the autoformer bumps the input to 400 volts to run it.) The
city inspector says he has to have the name plate re-stamped to read 208
volts since that's what is actually connected to it. Anyone ever hear of
this?

I don't know your city code, but that's a strange requirement. What is the
purpose of this label?

If there is a 110-120V fan in the shop, would your friend have to measure
the line voltage (let's say it is 118V) and relable the fan 118V? What if
the voltage drops to 116V during heavy load?

Maybe easier to just attach a voltmeter to each equipment.

The requirement is that all electrical equipment be used in accordance
with it's listing and labeling. In US practice a motor labeled with a
230 nominal voltage may be used on any voltage with a nominal value of
220 to 240 volts. As you can see the 208 volts being applied to this
load is outside the acceptable range of voltages for a 230 volt motor.
Motors intended to be operated at 208 volts must be listed for that
service. It is very common to have motors labeled 208/230 volts if they
are suitable for use at both nominal voltage levels. Many such motors
are provided with winding taps to allow for the two separate operating
voltages. IN the case of a machine that is listed to run at 230 volts
the remedy that is normally applied is to supply it from a properly
sized boost transformer that will boost the 208 supply to 230 volts.
Alternatively the manufacturer may be willing to exchange the supplied
transformer and label for one matched to the 208 supply.