In addition to the other posts:-
The maximum current will depend on two requirements - allowable voltage
drop and maximum conductor temperature.  - whichever requires the biggest
cable.
Voltage drop is your concern - only you know the application.
Maximum temperture will depend on a number of factors, not the least of
which is the maximum operating temperature allowed for that cable, airflow
available around the cable, ambient temperature and AC or DC operation.
In the case of AC there can also be significant losses if the cable runs
parallel to other cables or metalwork and the constuction is such that an
external magnetic field is generated. In this case frequency may enter the
equation also. For large cables skin effect also can come into it and two
parallel cables may be better than a single one of twice the cross section.

As an initial guide check with the manufacturer - normally they will have
tables or charts for the different cable types & sizes in different
environments.

Hope this assists.

Richard P



ok..power guys...

Whats the formula, given that I have the current and voltage, to calculate
the wire size that is required.

I'm talking large amounts of current...like 833Amps @120VAC

I know for 200A, I need a 4/0 wire.

Distances are rather short, something like 20 feet or less.


anyone?

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