Electricity_Study Flashcards
(20 cards)
What is the purpose of step-up transformers in power distribution?
To increase voltage and reduce amperage for efficient long-distance transmission.
Why are step-down transformers used near buildings?
To reduce high voltage to safe, usable levels for residential or commercial buildings.
What is a weather head?
A protective conduit entry point where power enters the building from the overhead line.
What is the purpose of the electrical meter?
To measure and track electricity usage for billing purposes.
Where should the panel (load center) be located in a building?
Very close to the meter for safety and fire-fighting access.
Why is proximity between the meter and panel important?
To allow quick power shutoff in emergencies and comply with safety codes.
What is the difference between centralized and decentralized power systems?
Centralized systems use distant power plants; decentralized systems generate power onsite (e.g. solar, wind).
Why is high voltage used for transmission?
It reduces amperage, allowing for smaller, more efficient cables.
What is the formula relating volts, amps, and watts?
Volts × Amps = Watts (Watts represent usable power).
What does a circuit breaker do?
It trips to break a circuit if too much current flows, preventing fires.
Why were fuses replaced by circuit breakers?
Because fuses had to be replaced after each fault, and people misused them (e.g., inserting pennies).
What is a load center?
Another term for an electrical panel where power is distributed and protected via breakers.
What are typical residential circuit amperages?
15 and 20 amps for most general use.
Why must a load center be accessible to firefighters?
To allow them to shut off power quickly in case of emergency.
What design challenge does exterior meter placement create?
Finding a discreet but accessible location that meets code and aesthetic requirements.
What is the role of decentralized systems in sustainability?
They reduce grid dependency and enable net-zero or energy-efficient buildings.
Why might a commercial building use floor-by-floor step-down transformers?
To manage high power loads efficiently with smaller cables.
What is the function of a bus bar in a load center?
To distribute power to individual circuit breakers.
What is the benefit of task-specific circuits in kitchens?
To handle simultaneous appliance use without overloading circuits.
What is the main design concern regarding electrical systems in early planning?
Providing logical, accessible locations for meters, panels, and service routes.
