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**-- Wire Type --**

There are 2 basic types of wire

Solid - A single solid conductor that is stiff and installed where the wire won't move

Stranded - Lots of smaller conductors bundled together to make a larger wire, flexible and can be rerolled frequently.

**-- Voltage --**

Most wire is capable of carrying 600 volts. The thickness of the insulation determines the voltage capability. If the voltage gets too high it will force it's way out of the insulation and arc to any conductor the wire comes into contact with.

**-- Current --**

The ability of the wire to carry amps is determined by the diameter of the conductor and the heat resisting ability of the insulation. Here is a chart of the normal capacities of common sizes of wire.

Gauge Amps

20 - 5

18 - 7.5

16 - 10

14 - 15

12 - 20

10 - 30

8 - 45

6 - 60

4 - 80

2 - 100

You should always read the writing on the wire to get more accurate ratings.

There are many kinds of wire, you just need to know what you've got and how to use it. If the insulation is able to resist high heat the wire can be rated to carry higher current. A 12ga wire in your house is commonly rated at 20 amps, but if it had high heat insulation it could be rated 40 amps and would need to be installed in a place where it's OK for the wire to get hot.

**-- Voltage Drop --**

When most of us work with wire we would consider that the wire has Zero Resistance. But wire does have resistance. The smaller size the wire is, the higher the resistance will be. Here is a chart of common wire sizes and the resistance in Ohms Per 1000 feet (305 meters).

Gauge - Ohms Per 1000 feet (305 meters)

20 - 10.2

18 - 6.4

16 - 4.02

14 - 2.53

12 - 1.6

10 - .1

8 - .63

6 - .4

4 - .249

2 - .156

Most normal electrical circuits have 2 conductors of wire to complete the circuit, so you would need to double the resistance in ohms in order to get the true resistance of a length of wire supplying a load.

The resistance in the wire and the amount of current used will cause any voltage to drop resulting in lower voltage at the end of the wire. The amount the voltage will drop depends on wire size and the amount of current flowing. A smaller or longer wire will lower the voltage. A larger current flow will also cause a voltage drop.

Here are some voltage drop calculators that will allow you to see what the voltage drop will be, after you input the wire Size, Wire Length and the amperage flowing in the wire.

http://www.csgnetwork.com/voltagedropcalc.html

http://www.nooutage.com/vdrop.htm

http://www.southwire.com/support/voltage-drop-calculator.htm

**-- Frequency & Skin Effect --**

A funny thing about wire is the Skin Effect. As the frequency of the voltage goes up, it stops flowing in the center of the conductor and begins to travel on the outside of the wire, or on the skin. The frequencies that we get from audio power are not high enough to worry about but it's good to know this happens. Here is a list of frequencies and the depth it would travel in a copper wire.

Freq Depth

10hz - 91mm

100hz - 6mm

1khz - 2mm

10khz - .6mm

100khz - .1mm

1mhz - .06mm

http://en.wikipedia.org/wiki/Skin_effect

Using stranded wire will reduce the problem with Skin Effect because each conductor acts all by it's self.