Compute the voltage drop along a 26-m length of household no. 14 copper wire (used in 15-A circuits). The wire has diameter 1.628mm and carries a 12-A current.
Please show work, so I can understand how to solve similar problems.
2007-03-28 13:57:45 · 2 answers · asked by vtchick1441 1 in Science & Mathematics ➔ Engineering
You can also use the formula for resistance if you have the value of the bulk resistance of copper. You can look up the bulk resistivity of copper on webelements.com.
R = res * length / area
res is bulk resistance and is given in units of ohm*m. Many times it's given in ohm*cm, so you have to convert to keep the units consistent. Notice that in the end, the units of length cancel out and you're left with resistance. (Note that area is the cross-sectional area, and length is in the direction of current flow.)
2007-03-28 16:44:21 · answer #1 · answered by vrrJT3 6 · 0⤊ 0⤋
The resistivity of 14 gauge copper wire is 8.28 Ohms/kilometer. Thus 26 m has a resistance of 26/1000 X 8.28 = 0.21528 Ohms. At 12 A the Voltage drop is 12 * 0.21528 = 2.58 Volts. Remember, this is for one wire so, for a normal household circuit, we add the contributions of both the hot and neutral giving a total drop of 5.166 Volts.
2007-03-28 22:29:33 · answer #2 · answered by Joe 5 · 0⤊ 0⤋