Final answer:
The three classes of wire used in an electrical system are the live/hot wire, the neutral wire, and the ground wire, represented in circuit diagrams by a straight line, a labeled line, and a line connected to an earth ground symbol respectively.
Step-by-step explanation:
In discussing electric circuits and the wire classes used in them, typically we only consider one class of wire in basic circuit diagrams. However, when considering the wiring in a home or for a defense application mentioned in the question, you might encounter a three-wire system. This three-wire system includes:
- Live/Hot wire: Typically represented by a black or red insulated wire, which carries the current from the power source to the load.
- Neutral wire: Often represented by a white insulated wire, which carries the current back to the electrical panel and completes the circuit.
- Ground wire: Usually shown with green insulation or a bare wire, this safety wire connects to the earth ground and diverts any fault current to reduce the risk of electric shock.
In circuit diagrams, these wires are usually depicted as follows:
- A straight line for the live/hot wire.
- A straight line, sometimes with a label 'N' or a different style line for the neutral wire.
- A straight line with a label 'G' or a line that connects to an earth ground symbol for the ground wire.
Circuit diagrams use these symbols to clearly communicate the electrical connections and components in a circuit. The black lines represent the wires, the red parallel lines symbolize the battery or voltage source, and a zigzag symbol depicts the resistor, including any resistance in the connections to the voltage source.