Wire Gauges: Explaining Sizes & Electric Current Capacity

[johnbrown11]

Hello,

Can anyone explain to me what wire guages are? It just says its a measurement of how large a wire is and how much electric current in can safley handle. Can anyone give more insight? Also, if I want to power something that requires 100watts what size of a gauge should i use and why?

Thanks

 

[hotvette]

Gauge is a measure of wire diameter (smaller gauge is larger diameter). Larger diameter wires have higher current carrying capability so it doesn't heat up too much and pose a fire hazard. Normal U.S. household wiring is 12 gauge I believe.

http://www.powerstream.com/Wire_Size.htm

 

[johnbrown11]

what does, Maximum amps for chassis wiring and Maximum amps for power transmission? Also what is chassis wiring?

 

[Bob S]

The copper electrical wire gauge is logarithmic in ohms/1000 feet:

0 Ga. 0.1 ohms/1000 ft
10 Ga. 1 ohms/1000 ft
20 Ga. 100 ohms/1000 ft
30 Ga 1000 ohms/1000 ft

The recommended max amps for a specific wire gauge is based on power loss and heating. e.g.,

Bare wire with convection cooling
insulated wire with convection cooling
insulated wire in bundles or in conduit
Chassis wiring

Bob S