Wire gauge is a measurement of the diameter of its conductor. Counter intuitively, as the numerical value of the gauge increases, the diameter of the wire decreases. To make it more confusing, not all of the numbers are used for the various gauges. Once wire gauge is below 1, several O's are added to indicate a larger wire.
The diameter of 2-gauge wire is 0.2576 inch. The diameter of 2/0-wire is 0.3648 inch. As the diameter increases, the wire's ability to carry more electricity increases. This is because a larger wire generates less heat with an electrical current in it.
Typical Service Sizes
Two-gauge copper wire is rated to handle 125 amps of electricity. The same wire made from aluminum is only rated for 100 amps of power. The 2/0-gauge copper wire can handle 200 amps of power before overheating. The same sized aluminum wire is rated for 150 amps of power. Protecting the wires with the correct sized breakers is important for electrical safety.
Both the 2- and 2/0-gauge wires are typically multistranded cables. This means several smaller conductors are twisted together to achieve a wider gauge wire.
Both of these wire gauges can carry enough electricity to seriously hurt or kill a person very quickly. Never touch any wire that is connected to a power source. Hire an electrician to do any work that requires wires of this gauge.