Types of Conductors Review Flashcards
The resistance of a wire depends on four main factors:
-Natural resistance (Resistivity)
-Length of the wire
-Temperature
-Cross-sectional area of the wire
Resistivity is often expressed in what unit?
ohms/mil-foot
AWG is also called ______and has been used since the mid-1800s to indicate a wire’s current carrying ratings.
Brown & Sharpe Wire Gauge
The term “_____” reference wires that are up to 1 AWG.
gauge
The term “____” refers to wires that are 1/0 AWG or larger. Expressed as 0, 00, 000 & 0000
aught
Four Types of Conductor Applications are……
- Power
- Fixture
- Communication
- Control
POWER: used to distribute the electrical energy within a building. What are the two types “power” conductors we use (CEC)?
- Service wiring
- branch wiring
Service wiring: usually large “_____” cables
Feeder
Canadian Electrical Code state that the minimum conductor size permitted in house is #___AWG.
14
If you are wiring in non-combustible building, which wire/cable should you use?
BX cable or conduit
If you are wiring in combustible building, which wire/cable should you use?
Loomex wire
Under Canadian Electrical code, how many volts is considered “extra low voltage.”
30 volts or less
Some use “___” conductors to minimize the electromagnetic and capacitive interference.
Shielded
What is a shield?
A metallic covering which is wrapped around the conductors - this acts as a Faraday cage.
What is a NMSC?
Non-Metallic Sheathed Cable.
Which location should you wire NMD 90?
Dry location
What is the Mineral Insulated Cable trade name?
Pyrotenax
4 main facts of Mineral Insulated Cable
- also called MI cable
- Has a magnesium oxide inside and a smooth copper sheath
- Fire resistant
- LWMI- light weight mineral insulated cable good up to 600Volts
What is the purpose of sheath around the conductor?
To protect the conductor from penetration or damages
Which cable should you use in residential buildings?
Loomex or Romex
Which cable should you use in commercial buildings
BX cable or conduit
What is another term used for FCC?
Under carpet cable
what does FCC stand for?
Flat Copper Conductor
Wire is insulated by dipping it in a varnish or enamel
Magnet wire
The ability of a material to be rolled or hammered into thin sheets.
Malleability
A mineral used for insulation and is capable of operation a very high temperature
Magnesium Oxide
An insulation use where flexibility and abrasion resistance are of prime importance.
Rubber
A type of insulation material that softens when heated, and conversely hardens when cooled.
Thermoplastic
What is the opposite of resistance?
Conductance
what is resistivity constant for copper?
10.4 ohm per mil-foot
A type of insulation made by impregnating cloth with varnish.
Varnish Cambric
A type of insulation that when held in a flame melts, drips and burns, but when the flame is removed, instantly self-extinguishes.
Flame Seal
What is a trade name for Polyvinylchloride?
PVC
The ability of a material to be drawn into a wire.
Ductility
What is the resistivity of aluminum?
17ohm per mil-foot
A phenomenon which may result in the connection points in a circuit losing their grip.
Cold Flow
What is a main advantage of using MI cable?
High temperatures applications
What is an enamel?
A special type of wire used within electrical equipment such as lighting fixtures.
Fixture Wire
Defined Ampacity
Ampacity is defined as the current in amperes a conductor can carry continuously under the condition without exceeding it temperature rating.
The ampacity of_____-temperature conductor is greater than the ampacity of_____-temperature.
8 60C copper has an ampacity of 40A
High, low
For Example,
#8 90C copper has an ampacity of 55A
