Electrical (1.2)

Question 1

Energy flow through a _________ because of a difference in electrical change between two points in a circuit

Answer 1

conductor

Energy flow through a conductor because of a difference in electrical change between two points in a circuit

Question 2

Where can service utilities be placed/sourced from?

Answer 2

Underground and overhead service depending on accessibility

Question 3

Overhead placement of main power source to building pros/cons?

Answer 3

Pro: less expansive, easily accessible for maintenance, can carry high voltages over long runs
Cons: not ideal in urban settings

Question 4

Underground placement of main power source to building pros/cons?

Answer 4

Pro: Best for urban areas, for high load carrying
Con: more expensive,

General - cables are run in pipe conduit or raceways for protection

Question 5

Know the way electricity flows, list out the processes

Answer 5

https://www.studyforfe.com/blog/fundamentals-of-single-line-diagrams/

Utility Source(company) –> Meter –>Transformer (outdoor pad/ventilated interior)–> main switchgear –> main switchboard –> panelboards –> branch circuits —> outlets/appliances

Question 6

What is the purpose of a switchgear

Answer 6

Measures, controls and distributes the power at the main electrical panel,
It includes a main disconnect of switches, fuses, and circuit breakers protecting the electric power supply to a building (BCI 11.31)

Question 7

what is a service switch?

Answer 7

Within the switchgear - the main disconnect for entire electrical service (BCI 11.31)

Question 8

What brings power from the main panel to the subpanels

Answer 8

Feeder cables bring power from the main distribution panel to sub panes in large buildings

Question 9

What do branch circuits do?

Answer 9

Branch circuits distribute power from subpanels throughout the building (BCI, 11.32)

Question 10

What is the purpose of a transformer

Answer 10

• Transformers are typically utilized by larger building
• Used to step down from a high-supply voltage to service voltage
• Placed close to and outdoor pad or in a well ventilated room with a wall adjacent to exterior wall

Question 11

Explain this diagram

Answer 11

main utility line enter building through cables into meter (records usage) >then into transformer > into switchgear cables that run through closet room panels that steps down power tovappliances

Question 12

What is this type of distribution? Where would you see this type?

Answer 12

type of distribution phase:
120/240V Single phase, 3wire
Residential and small commercial bldg

Question 13

What is this type of distribution? Where would you see this type?

Answer 13

Distribution type:
120/240V Three phase, 4wire
Commercial bldg

Question 14

What is this type of distribution? Where would you see this type?

Answer 14

Distribution type:
three phase 4 wire (wye connected)H
Large commercial

Question 15

Electrical operating cost in a single tenant commercial building can be minimizes by using which of the following techniques? Choose the four that apply
A. Daylighting
B. Indirect lighting
C. Load control
D. Multiple metering
E. Occupancy sensors
F. Light emitting diode lamps (LED)
(ballast Ch 17)

Answer 15

A. Daylight
used to reduce the amount if electrical lighting needed
C. Load control
A way to avoid peaking demand electrical charges by automatically or manually shutting off nonessential before peak demand
E. Multiple metering
Used for multitenant spaces would not reduce savings for commercial bld but does per individual tenant or they only are charge what they use not what others use
F. Light emitting diode lam LED
Minimize power required

Question 16

High voltages are used in commercial buildings because
A. Conductors and conduit can be smaller
B. A wider variety of loads can be accommodated
C. Commercial buildings require more power
D. Transformers can step down the voltages to whatever is required
(ballast Ch 17)

Answer 16

A. Conductors and conduit can be smaller
- as voltages increase, current may be decreased and the system will still provide the same amount of power
- lower currents require smaller conductors
- for large commercial buildings smaller conductors means less expense in conductors and conduit as well as easier installation on smaller wires

Question 17

Which would be the best location for a transformer for a larger school building?
A. On the power pole serving the building.
B. In a separate room near the exterior
C. Outside on a transformer pad close to the main switchgear
D. In a protective shed where power from the utility company enters the property

Answer 17

B. In a separate room near the exterior
- best for protection, ventilation and ease of installation and removal.
- large school would require voltage service service and step down transformers provided by owner
- having it on a pad outside would expose it to weather and vandalism