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Building Utilities > Electrical > Flashcards

Electrical Flashcards

1
Q

a phenomenon or manifestation;

Principally made up of atoms, protons and neutrons

A

Electricity

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2
Q

Electricity has 2 general classes:

A

Dynamic electricity which is a Electrodynamic

Static Electricity also known as Electrostatic

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3
Q

It is a flow in an electric circuit?

A

Electric Current

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4
Q

Electric current 2 classifications:

A

Direct and Alternating Current

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5
Q

Flows in one direction (from negative to positive)

UNiform in strength

Battery or a dry cell

2 types: continuous and fluctuating

A

Direct Current

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6
Q

reverses direction of flow at regular intervals

Frequency of 60 cps (60 hertz)

Phase: SP or 3P

230 VAC, 60 hz, SP

Full wave rectified single Phase AC

FullWave Rectified Three phase ac

Half Wave rectified AC

Single Phase alternating current

A

Alternating Current

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7
Q

Frequency of an Alternating Current

A

60 hrtz or 60 cps

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8
Q

This rectified alternating current for which the rectified is so connected that the reverse half of the cycle is “turned around” and fed into the circuit flowing in the same direction as the first half of the cycle. This produces pulsating DC but with no interval between the pulses (referred to as single phase full wave DC)

A

Full Wave rectified Single Phase AC

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9
Q

When three-phase alternating current is rectified the full0wave rectification system is used. The result is DC with very little pulsation, in fact only a ripple of varying voltage distinguishes it from straight DC

A

Full wave rectified Three Phase AC

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10
Q

When a single phase alternating current is rectified in the simplest manner, the reverse half of the cycle is blocked out entirely. The result is a pulsating undirectional current with intervals when no current at all is flowing (referred to as “half wave or as pulsating direct current)

A

Half Wave Rectified AC

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11
Q

This term refers to a simple current, alternating in direction. Commercial single phase current follows sine wave. Such a current requires only two conductors for its circuit. Most common commercial frequencies are 25, 50 and 60 cycles per second.

A

Single Phase alternating current

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12
Q

Commercial electricity is commonly transmitted as three single phase currents, that is, three separate current following separate sine curves, each at 60 cycles (or other frequency) per second, but with the peaks of their individual curves one-third of a cycle apart. At least three (sometimes four) conductors are required for three - phase alternating current.

A

Three phase alternating current

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13
Q

A magnetization technique utilizing short circuited AC or condenser discharged DC. Very high magnetizing current are possible for short durations (1/100 to 1/1000 sec) with out the use of transformers. A pulsed magnetization applies high fileds for brief periods. A slight variation of pulsed magnetization is impulse magnetization (flash magnetization).

A

Pulsed and Impulse Current Magnetization

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14
Q

Fixed polarity

Steady or Continuous; Vary in magnitude (Fluctuating)

Steady value

Easier to measure: 1.5 Volts

A

Direct Current DC

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15
Q

Reverses polarity

Varies vetween reversal

Stepped up or down

Easier to amplify from 110V and more

A

Alternating Current

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16
Q

Path for electric current with EMF applied

A

Electric Circuit

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17
Q

An electrical layout

Composed of

Close Circuit and Open Circuit

A

Circuit Diagram

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18
Q

A circuit diagram, comple, continuous path

A

Close Circuit

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19
Q

A circuit diagram, Broken, incomplete and disconnected

A

Open Circuit

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20
Q

Types of Circuits

A
  1. Parallel Circuit
  2. Series Circuit
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21
Q
A

Simpel electrical Circuit

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22
Q
A

Series and parallel Circuit

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23
Q
A

Simple Electrical Circuit

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24
Q
A

Parallel Circuit

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25
Q
A

Series Circuit

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26
Q

relationship of EMF, Current and Resistance

Formula is I=V/R

R = V/I

V = IR

A

Ohms Law

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27
Q

what is I in ohms law?

A

Current (Ampere)

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28
Q

V in ohms law

A

EMF or Volts

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29
Q

what is R in Ohms

A

Resistance (Ohms)

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30
Q

pressure or force, unit of electrical pressure or potential. Pressure makes electricity flow throug a wire. For a particular electrical load, the higher the voltage the greater will be the amount of electricity that will flow.

A

Voltage (Volts)

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31
Q

Force which causes movement of electricity in a conductor.

A

EMF or Electromotive Force

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32
Q

inherent in wires (conductor); term for flow of electricity is current: unit used to measure the magnitude of an electric current

The specific quantity of electrons passing a point in one second. The amount of current in amperes, that will flow through a circuit must be known in order to determine proper wire sizes and the current rating of circuit breaker and fuses

A

Amperes (amps)

use Ammeter

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33
Q

friction

inherent in insulator,

electricity flowing through a material always meets with some resistance. Insulators like wood, glass and plastic have a hign resistance,

Copper aluminum and silver have low resistance and are therefore good conductors of electricity.

A

Ohms

use Ohmeter

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34
Q

does not consume electricity

A

Device

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35
Q

rate of power

power consumption

The amount of power required to light lamps, heat water, turn motors and do all types of work is measured in ___. this depends on both potential and current. Current (in amperes) multiplied y potential (in volts) equals power (in watts)

A

Watts

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36
Q

The actual energy used (the watts utilized) for work performed is the basis for figuring the cost of electricity. The unit used to measure the consumption of electrical energy is the _____. A kilowatt is ____ watts. An hour of course is a unit of time. A 1000 watt hand iron operating for one hour consumes one kilowatt hour. The device used to measure the kilowatt hours consumed in the watt-hour meter.

A

kilowatt hour

1000 watts

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37
Q

AC generator

A

Alternator

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38
Q

Producing Alternating Current

In electrical power generation and use alternating ucrrent is the preferred and natural form of electricity. power as AC can be transformed to a high voltage which enables low loss transmission from power stations to towns and industry where it is transformed down for homes, offices and factories. An _____ produces alternating current at ___ cycles per second (herts)

A

electrical alternator/generator

50

39
Q

Mechanical Energy to Electrical Energy

A

Generator

40
Q
A

Portable Generator

41
Q
A

Generator Set

Genset

42
Q

Electrical Energy to Mechanical energy

A

Motor

43
Q

Electrochemical; Electrolysis

A

Battery

44
Q

Types of batteries:

A

Primary - nonrenewable

Secondary - rechargable

45
Q

Illustrate components of a battery

A
46
Q

The power dirving the rotor, fomr a power source, eg. a steam or gas turbine, is transferred to electrical power in the stator winding. In the case of a large generator in a coal or nuclear power station, to achieve 50 hertz the rotor has two poles ofa magnet N and S which rotate past the top red winding of the stator 50 times a second (or 3000 revs per minute - rpm). Each time the N passes the R (for red stator winding see diagram above) electrical current is induced passes the R it is a maximum in the reverse direction. This is_____-

A

single phase AC.

47
Q

Electrical Power sources and alternative power sources;

aka. Power Distribution

A

Electric power is generated from several sources of energy: wind water nuclear fossil fuel solar (photovoltaic, and solar energy directly into an electric current. All other energy sources are harnessed to produce a rotary mechanical motion that drives electrical generators. The generators harnessed to produce a rotary mechanical motion that drives electrical generators. The generators convert movement into electricity. Transformers are used to “step up” (increase) the electrical power to very high voltages (hundreds of thousands of volts) for transmission by wires over long distances. Wherever the transmission lines enter an industrial or residential community for local power distribution, large transformers are used to “step down” the voltage to a few throusand volts. Smaller transformers set on poles or in underground vaults are used for final distribution to small groups of houses or individual factories. Usually 110 and 220 volts are delivered to residences.

48
Q

Service Entrance

A

Power is supplied to a building through a service entrance. Three heavy wires, together called the drop, extend from a utility pole or an underground source to the structure. These wires are twisted into a cable. At the building, overhead wires are fastened to the structure and spliced to service entrance wires that enter a conduit through a service head. In planning overhead service drop paths, minimum height requirements for connector lines must be carefully followed. If these distnaces cannot be maintained, rigid conduit, electrical metallic tubing, or busways (channels, ducts) must be used.

49
Q

How Underground Service Entrance works?

A

If the service is supplied underground, three wires are placed in a rigid conduit. An underground service conduit is brought to the meter socket. An underground service entrance includes a watt hour meter, main breaker and lightning protection. Automatic brownout equipment is also required by many codes for new construction, All electrical systems must be ground through the service entrance.

50
Q

System Components of Building:

(3)

A

Wirings and Raceways

Power Handling Equipments

Utilization Equipments

51
Q

Wirings and Raceways

____ offers low resistance

A

Conductors

52
Q

Wirings and Raceways

__ prevents flow of electric current.

A

Insulators

53
Q

Wirings and Raceways

__ functions as a channel

A

Raceways

54
Q

Category 2: Power Handling Equipments

Components of Power Handling Equipments (5)

A

Transformer, Switchboard or Switch Gear, Panel Board, Service Switch/Safety Switch, Circuit Breaker or Fuse.

55
Q

How Power Handling Equipments Work?

Service Distribution:

A

Electrical current is delivered throughout a building through a distribution panel, or service panel. The size of a distribution panel (in amperes) is determined by the total load requirements (watts) of the entire building. Watts can be converted to amperes by dividing the total (an future) watts needed by the amount of voltage delivered to the distribution box.

56
Q

Most residences require a distribution panel with a capacity of ___ to ____ amps. The Philippine Electrical Code (PEC) minimum for new residential consstruction is ___ amps. To computed the total load requirements, the watts needed for each circuit must first be determined.

A

100 to 200

60

57
Q

the actual use of electricity (eg. Fixtures and switches)

A

Utilization Equipments

58
Q

Branch Circuits

From the distribution panel, electricity is routed to the building through_____. A ____ is a circular path that electricity follows from the power supple source to a light, appliance, or other electrical device and back again to the power supply source. If the electrical load for an entire building were placed on one circuit, overloading would occur. Thus branch circuits are used. Each circuit delivers electricity to a limited number of outlets or devices.

Each circuit is protected with a ______ . A circuit breaker is a device that opens (disconnects) a circuit when the current exceeds a certain amount. When a breaker opens, or “trips”, the power to the branch circuit is disconnected. If the sum of the current drawn by the branch circuits exceeds the rating of the main circuit breaker, the main breaker will trip. This protects the service entrance wires and equipment from overheating and damage. Circuit breakers that trip can be reset.

A

branch circuits

circuit

circuit breaker

59
Q

Lighting Circuits:

Lighting circuits are connected to lighting outlets for the entire building. Different lights in each room are usually on different circuits so that if one circuit breaker trips, the room will not be in total darkness.

In all dwellings other than hotels, the PE requires a minimum genral lighting load of ______ of floor space. However, the amount of wattage demanded at one time (demand factor) is calculated at____ only for the first 3000 watts; _____ is used for the second 17,000 watts, and ____ is used for commercial demands over 120000 wattts. Thus, the general lighting load planned for a 1500 sq. ft. house would be 3525 watts, not the full 4500 watts. It is calculated as follows.

A

3 watts per square foot

100%

35 percent

25 percent

60
Q
A

two

1500 watt load

61
Q
A

single large electrical appliance

starting load

20 amps

ground fault circuit interrupter receptacle

62
Q
A

1/40 second

.005 amps

63
Q

GFCI

A

Ground-Fault Circuit Interrupter

64
Q
A

GFCI

65
Q

In new construction GFCI receptacles must be located with each convenience outlet neat water sources and or pipes in the bathroom, kitchen, garage, laundry and outdoors. Any receptacle located within___ or within ___ of the inside of a permanently installed swimming pool must also be wired through a GFCI. GFCIs are also required if outlets are placed in unfinished crawl spaces below grade level.

A

10 or within 15ft

66
Q

Load requirements

Kitchen Range

A

12500 watts

120/240 volts

3 - #6 plus ground

50A

67
Q

Load requirements

Over (built in)

A

4500 watts

120-240

3 - no 10 plus ground

30A

68
Q

Load requirements

Range top

A

6000 watts

120- 240

3 - no 10 plus ground

30A

69
Q

Load requirements

Refrigerator / Freezer 16-25cubi ft.

A

800 watts

120

2- no 12 plus ground

20A

70
Q

Load requirements

Laundry Washing Machie

A

1200 Watts

120

2 - no 12 plus ground

20A

71
Q

Load requirements

Water Heater

A

3000 - 6000 watts

72
Q

Load requirements

Television

A

300 Watts

120

2 - no 12 plus ground

20A

73
Q

BX; flexible metal conduit with a wire bundle, consisting of individually insulated conductors covered by a flexible spiral wound layer of metal. Most often used for feeder and service power in commercian and multi story residential applications, the steel or aluminum clad cable is more resistant to damage from puncture or abrasion than non metallic sheathed cable. Pre wired at the factory.

A

Flexible Metal Clad (FMC)/Metal Clad (MC)/ Armored Cable (AC)

74
Q

ROMEX

Sheath

Used for both exposed and concealed work in normally dry locations at temperatures not to exceed 90 celsius degrees as specified in the Philippine Electrical Code; primarily used in residential wiring as branch circuits for outlets, switches and other loads, may be run in air voids of masonry block or tile walls where such walls are not wet or damp locations Voltage rating for NM-B cable is 600 volts.

A

Non Metallic Sheated Cable (NMC/NM)

75
Q
A

BX Wire

76
Q
A

ROMEX

77
Q

General Wiring:

eg. THHN

A

Thermoplastic (PEC)

78
Q
A

THHN

79
Q

THHN meaning

A

Thermoplastic, high heat, Nylon coated.

THHN wire without a dual approval of THWN is not water resistant. The added “W” stands for water resistant so that it could be installed outdoors and in conduit when THHN wire could not.

80
Q

THW meaning

A

Thermoplastic, Heat and water resistant wire. This acronym is missing the “N” for nylon coated. The nylon coating looks like the little piece of plastic over a shoe lace and protects the wire in a similar fashion. Without the nylon coating, the wire will be slightly cheaper and provide less environmental protection to THW wire. It’s actually difficult to find THW wire without the additional approvals of THHN and THWN because they were all combined into one.

81
Q

THWN meaning

A

Thermoplastic Heat and Water Resistant Nylon Coated

82
Q
A

THHW

83
Q
A

THWN / THWN -2

84
Q
A

THW/THW-2

85
Q
A

TW

86
Q
A

XHH

87
Q

XHHW

A

Cross-Linked High Heat Water Resistant Insulated Wire

88
Q
A

XHHW / XHHW - 2

89
Q
A

Mineral INsulated (MI) Jacketed

90
Q
A

MI

91
Q
A

Shilded Nonmetallic Sheated Cable (SNM)

92
Q
A

USE/USE-2; Service entrance (SE/USE)

93
Q

Electrons in Motion

A

Electricity

94
Q
A

Building Utilities (2 decks)

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