AWG

[JRGarcia13]

Hello, this forum is the best by far.
My question is:
Is there a formula to determine what wire size I need for a "electrical" run:
Example:
I'm using 120VAC
Wire:Copper
Length:100ft
The wire will handle 15Amp at Mximum.

What wire gage (AWG)I need?
Is there a formula?

Thanks in advance.

José.

 

[davidbeach]

It depends. It depends on where you are (code requirements), how much voltage drop you will accept, type of insulation, temperature, number of current carrying conductors in the conduit.

 

[itsmoked]

And what is at the end of this run... i.e. a motor?

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[JRGarcia13]

Thanks for your responses.
Let's take the simplest case scenerion:
-Voltage drope at 3%, I thinks that is what the code call for.
-Temperature: about 80F
-Only carrying conductor in conduit.
- End of run: Lighting

 

[Senselessticker]

Check out Table 9 in the NEC "Handbook" if you are trying to meet NEC. There is a good example. I'm "guessing" you'll need at least a #10 or perhaps a #8.

 

[JRGarcia13]

Thanks, I don't own a NEC hanbook but I'll go to Barnes and Noble this weekend and take a free reading on it.

However, I have seen some formulas ONline, but I don't understand them just yet. I'll take a second look....

JRGarcia.

 

[waross]

The easy formulas are for DC currents.
There are some additional factors involved in AC voltage drops. Rather than trying to calculate the reactive impedance of the cables, we use the voltage drop tables in the NEC or CEC.
This method has the additional advantage in that the results are accepted by the inspection departments.
yours

 

[davidbeach]

I doubt it will be the only current carrying conductor in the conduit; how will the current return?

 

[cuky2000]

Check the enclose calculator:

http://www.elec-toolbox.com/calculators/voltdrop.htm

 

[JRGarcia13]

Thanks for all the advice.
I'll post my findings Friday.

JRGarcia.