Wiring Tables and Conductor Size Flashcards
What code is used throughout the industry to determine the conductor size for most applications?
National Electrical Code
When was the American Wire Gauge standardized?
1857
Why are gauge sizes important?
They are important for determining the current carrying capacity for a conductor.
How are gauge sizes determined?
They are determined by the number of draws necessary to produce a given diameter of wire.
What is the largest AWG size?
4/0
What is one factor that determines the resistivity of a wire?
The material that the wire is made from.
What is two factor that determines the amount of current a conductor can carry?
The type of insulation used and the surrounding air temperature.
What is the maximum operating temperature?
The highest operating temperature of a conductor. Determined by the type of insulation around the conductor.
If conductors are used in a location that has a higher ambient temperature, the resistance of the wire __________
Increases
What are three factors that NEC requires electricians to follow when choosing a conductor for a specific job?
The conductor ampacity must be 125% greater than the current rating of a continuous load, the temperature rating must not exceed the lowest temp. rating of any connected conductor, termination, or device, and the conductor must be selected from Table 310.15
What is an electric duct bank?
A group of duct banks buried togather
When a duct bank is used, the center points of individual ducts should be separated by a distance of _________
No less than 7.5 inches
What are four factors that determine the resistance of a wire?
- The material that it is made from
- The diameter of the conductor
- The length of a conductor
- The temperature of the conductor
What is one condition in which parallel conductors should be used?
When the conductor is very large.
What are five conditions that must be met when conductors are connected in parallel?
- They must be the same length
- They must be made of the same material
- They must have the same circular mil area
- They must be terminated or connected in the same manner.
