Confidence Level
BASIC DEFINITIONS
- Voltage (V): the “push” behind electricity
- Current (A): how much electricity is moving
- Resistance (Ω): how hard it is to move electricity
- Power (W): the total work being done
SERVICE DROP
- The service drop is the overhead wiring from the utility pole to the house.
- Sometimes called “overhead service.”
- If underground, it is called a service lateral.
- A splice joins wires together and these are found where the service drop or service lateral ends.
- A drip loop (U-shaped bend) is used to prevent water from entering the service entrance.
- A three-wire service drop (single-phase) is most common in houses:
- 2 hot wires (typically black)
- 1 neutral wire (white, or sometimes black as well)
- Neutral may also act as support.
- If only two wires are seen, it is usually an outdated 120V system needing replacement.
- Four-wire service (three-phase) is common in commercial or large farm buildings and is not covered in residential inspections.
- Typical residential service is 240V single-phase from a three-wire drop.