Finding Resistance in Chapter 9 Table 8

[nbabcock03]

When finding resistance for a problem like voltage drop, and the conductor type is unspecified, which column of Chapter 9 Table 8 is to be used when searching for ohm/kFT. I assume copper unless otherwise specified to be aluminum. I am unsure whether to use uncoated/coated and solid/stranded when the conductor is not specified in the problem.

For example, when solving;

What's the voltage drop of two 12 AWG conductors that supply a 10A, 120V, single-phase load located 100 ft from the power supply?

With VD = I x R

How would I find the resistance of my 12 AWG conductors?

 

[Deltaforce]

When finding resistance for a problem like voltage drop, and the conductor type is unspecified, which column of Chapter 9 Table 8 is to be used when searching for ohm/kFT. I assume copper unless otherwise specified to be aluminum. I am unsure whether to use uncoated/coated and solid/stranded when the conductor is not specified in the problem.

For example, when solving;

What's the voltage drop of two 12 AWG conductors that supply a 10A, 120V, single-phase load located 100 ft from the power supply?

With VD = I x R

How would I find the resistance of my 12 AWG conductors?

As exercise, check with different parameters, coated, solid vs uncoated stranded for copper conductor 12awg, to see resistance not differ much, though uncoated stranded standard assumption

 

[ggunn]

When finding resistance for a problem like voltage drop, and the conductor type is unspecified, which column of Chapter 9 Table 8 is to be used when searching for ohm/kFT. I assume copper unless otherwise specified to be aluminum. I am unsure whether to use uncoated/coated and solid/stranded when the conductor is not specified in the problem.

For example, when solving;

What's the voltage drop of two 12 AWG conductors that supply a 10A, 120V, single-phase load located 100 ft from the power supply?

With VD = I x R

How would I find the resistance of my 12 AWG conductors?

If it isn't known whether the conductors are aluminum or copper, you cannot determine the resistance and voltage drop.

 

[winnie]

0) Be careful about being too accurate given the information given. Every calculation will have error bars on it.
1) In general assume uncoated, and pick solid for < 10awg, stranded for larger.
2) You will always find exceptions to the above (I'm partial to using 12ga stranded during my installations )
3) The difference in resistance between solid and stranded of the same gauge is similar to the difference caused by a 10C temperature change. So if you are going to try to be extra precise by considering the difference between solid and stranded conductors, then you should also be thinking about the operating temperature of the wire. (See note 2 at the bottom of the table)

-Jonathan