Conductor Sizes Flashcards
What is the relationship between conductor size and resistance?
The bigger the conductor (like a larger pipe), the lower the resistance, which allows it to safely deliver more power.
How do copper and aluminum conductors compare?
Copper has less resistance to electron flow than aluminum, so aluminum conductors are sized one to two sizes larger than equivalent copper conductors for the same amperage.
Why is single-strand aluminum wiring problematic?
Single-strand aluminum branch circuit wiring should be evaluated by a licensed electrical contractor because it can be prone to issues, especially in older homes. Multi-strand aluminum wires are typically not problematic.
What is the conductor size for a 200-amp service?
For a 200-amp service, the service-entrance cable (SEU) will have two 4/0 aluminum conductors for the “hots” and a bare 2/0 aluminum ground or neutral conductor.
What is the minimum wire size for a 20-amp breaker?
A 12-gauge copper wire is the minimum size for a 20-amp breaker.
What is the minimum wire size for a 30-amp breaker?
A 10-gauge wire is the minimum size for a 30-amp breaker.
What is overcurrent protection?
Overcurrent protection is provided by circuit breakers or fuses. These devices prevent conductors from carrying excessive current, which could lead to dangerous overheating.
What should home inspectors look for in overcurrent protection?
Home inspectors should ensure that the maximum breaker rating does not exceed the allowable ampacity of the conductor, based on the wire size.
What type of wiring is considered a major defect in homes built between the 1960s and 1970s?
Single-strand (solid) aluminum branch circuit wiring is considered a major defect and should be reported by home inspectors.
What is AWG?
AWG stands for American Wire Gauge, a standardized wire gauge system used to measure conductor sizes.
