Electrical Layout and Estimate Flashcards
Is a form of energy generated by friction, induction or chemical change, having magnetic, chemical and radiant effect.
Electricity
Electrons in Motion
Electricity
date when electricity was accidentally discovered by Greeks.
600 BC
He is an english physicist, considered Father of Electricity, after publishing his studies on Electric Attraction and The Electric Force
William Gilbert
Electricity consists of (3):
Electrons
Neutron
Proton
The ___ is the negtaively charged particle of an Atom sometimes referred to as the negative charge of electricity.
Electron
On the other hand, the ____ is the positively charged particle of an Atom which is sometimes referred to as the positive charge of electricity that weighs about 1850 times as much as the Electron.
Proton
____ is that particle of an Atom which is not electrically charged and weighs slightly more than the proton.
Neutron
Is the term applied to an atom or molecule which is not electrically balanced. It is an atom or molecule that is electrically cahrged. It simply mean there is a loss or gain of one or more electrons. It occur when the electrons in the atom is loosened through friction by another atom. Therefore, the presence of electrons in any organic or inorganic substance is a fact, that electricity is always present.
Ion
Volt or voltage is the electrical pressure that causes the electrons to move theough a conductor (wire). It is an Electromotive FOrce
Volt or Voltage
Comparatively, to have 12 volts is like having 12 pounds of water pressure inside the pipe of a water system. Thusm the higher the voltage, the more electricity will be forced to flow.
Volt was named after this Italian scientist who discovered that electrons flow when two different metals are connected by a wire and then dipped into a liquid that conduct or carry electrons.
Alessandro Volta
Is the standard unit used in measuring the strength of an electric currrent, named after Andre M Ampere.
Ampere
It is the amount of current flow, sent by one volt through the resistance of one Ohm,. When there is too mush flow of electricity in a small conductor or wire, heat is produced which eventually may blow-off the protective devise called fuse, or burn the wire insulator and create fire.
Ampere
Watt is name after _____, a scottish inventor.
James Watt
Is the rate or measure of power used or consumed. It represents the equivalent heat volts and ampere consumed by lights, appliancces or motors.
Watt
Refers to the wire installations that supply current to light and convenient outlets.
Circuit
IS the firction or opposition to the flow of current by the wires and transformers, analogous to plumbing installation, where the flow of water is subjected to resistance caused by friction between the water and the inside wall of the pipe, and the various form of turns and fittings.
Resistance
For direct current (DC), friction is ______
Resistance
For alternating current (AC), friction is ______.
Impedance
Factors that influences Conductor Resistnace. (4)
Composition of the conductor
Length of wire
Cross sectional area of wire (eg the bigger the section the lower the resistance)
Temperature
is the flow or rate of flow of electric force in a conductor.
Electric Current
Types of Electric Current
DC
AC
flows in one direction, the flow is said to be from negative to positive, a dry cell or storage battery.
DC
Constantly reverses its direction of flow, it is generated by machine called generator, this type of current is universally accepted because of its unlimited number of applications with the following advantages.
Easily produce
cheaper
it can be transformed to higher voltage and drop it to low voltage
more efficient compared to DC
Alternating Current
who advocates the DC
Thomas Edison
who advocates the AC
George Westinghouse
The AC current goes through one positive loop and one negative loop to form one complete cycle that is continuously repeated.
The number of times this cycle of plus and minus loop occur per second is called the _____ expressed in cycles per second normally referred to as Hertz.
Frequency of Alternating Current
The hertz is named after German physicist ___
Heinrich Hertz
Frequency of DC is ___
Zero
unit of Resistance
OHMS
The higher the Voltage, the ___ the Current.
Larger
(direct proportional)
The higher the resistance, the ____ the current.
Lower
(inversely proportional)
Ohms law formula for DC:
I = V/R
whre
I = current
V = voltage
R = resistance for DC electricity
Ohms law for AC:
I=V/Z
where
I - Current
V= Voltage
Z= impedance
unit of Current
Ampere (A), amp
Under the principles of DC electricity. Power is the product of voltage and current.
Watts = Volts x Amperes
Under the principle of AC electricity, the product of volts and amperes is equal to the quantity called volt-ampere (va) which is not the same as watts, thus:
Volt Amperes = Volts x Amperes
To convert volt-ampere to watts or pwoer, a power factor (pf) is introduced, and to get power in an AC circuit, we have the following formula:
Watts = Volts x Amperes x power factor
W=V x I x pf
A 12 amperes electric fan and blower with a power of 0.85 was connected to a 240 volts convenient outlet (CO). Calculate the current and power in the circuit
W = 240v x 12 amp x 0.85
W = 2,448 watts
An electric motor has a trade mark label of 2 horse power, 240 volts, 15 amperes,. Calculate the motor power factor.
Assume motor efficiency say 85%
1 HP is equal to 746 watts,
746 x 2 = 1492 watts
Efficientcy = 1492/85
1755 watts
For AC Current:
power = volts x amperes x power factor
power factor = (power/volts x amperes)
pf = 1755 / 240 x 15amp
pf = .4875
Volt-Amperes = 240 v x 25
Volt Amperes = 3600 va
The higher the voltage, the larger the current, and the higher the resistance, the lower the current.
Ohms Law
In 1962, ____ a german scientist, discovered the relationship between the Current, Voltage and resistance now referred to as the OHms Law.
George Simon Ohm
Ohms Law formula:
I = V/R
where
I = current (ampere)
V= electromotive formce (volts)
R = resistance (ohms)
Determine the current flow in a circuit having a resistance of 5 ohms on a 120 volts and 240 volts current supple. (circuit refers to electrical wiring installation.
For 120 Volts
I=V/R=120/5
I = 24 amperes
For 240 Volts
I = V/R = 240/5
I = 48 Amperes
It can be conclueded from the foregoing illustrations that a 240 volts circuit is better choice than using a 120 volt circuit as computed with 48 and 24 amperes respectively.
Power =____
Voltage x Ampere
Two types of circuit
Parallel Circuit
Series Circuit
A single path exist for current flow, that is, the elements are arranged in a series on after the other with no branches. Being a single path in a seriesarrangement and resistance simply adds.
Series Connection
Voltage Total = V1 + V2 + V3
Resistance Total = R1 + R2 + R3
Two Automobile headlights are connected in a series to a 12 volts battery each having a resistance of 1 ohm. What is the current flowing in the circuit?
V = 12volts
Total resistance = R = r1 + r2
I= v/r
= 12v/2
I = 6 amperes
Another example of a series connection is the _____ having a single wire supplying the current. When a single bulb breaks off, the flow of current is also cut off, putting the entire series of light into total darkness.
String of Christmas Light
The parallel circuit is sometimes referred to as ____ where the loads are placed across the same voltageconstituting a separate circuit
Multiple Connections
___ is the standard arrangement for house wiring connections wherein the lights constitute one parallel grouping and the convenience wall outlets constitute the second parallel grouping.
Parallel CIrcuit
The fundamental principle under this type of circuitry is that “loads in parallel are ____ for current, and that each has the ___ voltage.
additive
same
Ohms Law
AS resitance increases, current decreases. When current rises instantly to a very high level, the condition will constitute a ____. Hence, it is mandatory for all circuit to be protected by fuse or circuit breaker that automatically open and disable the line in case of a fault or short circuit.
Short Circuit
_____ is a simple static device consisting of a magnetic core wherein the primary and secondary windings are made. The voltage is directly proportional to the number of windings or turns. Thus, if a 120 AC will be connected to the left side containing 100 turns, 240 volts would be on the right side containing 200 turns.
Transformer
__ is the technical term for the common word work.
POwer
___ is the product of power and time expressed in the following equiation:
ENergy or Work= Power x time
Work
In electrical terms, energy is synonymous with ___.
Fuel
___ is expressed in units of BTU (calories), foot pound (joules) or kilowatt hour.
Energy
Under the english unit system, the unit of power is expressed in “____(3).
Horse power, BTU per hour, watt and kilowatt
Under the Metric system or SI, it is correspondingly expressed as ____ (3)
Joules per second, calories per second, watts and kilowatts
In physical terms, ___ is also the rate at which fuel or energy is used and expressed as liters of fuel per hour, cubic meter of gas per minute or tons of coal per day. etc.
Power
The measuring unit of electric power is the ___
Watt
1kW =
1000watts
Derivation of W= VI
Watt = I2 x R
Ohms Law:
V = IR
since W = I2 R
W = VI
where.
W=watts
R=Ohms
I=Amperes
V=Volts
A mercury lamp having a hot resistance of 50 ohms, is connected to a socket with 240 volts current supply.\
a. How much current, flows through the lamp?
b. calculate the power drawn
I = V/R;
I = 240/500:
I = 4.8 amperes
Where power factor (pf) in a purely resistive circuit, such as those with only electric heating elements, impedance or resistance power factor (pf) is equal to 1. Thus
W= VI x pf
= 240 x 4.8 x 1
= 1152 watts
=I2R
= (4.8)2 x 50
= 1152 watts
Determine the monthyly energy consumption of the following appliance:
Water Heater; Load of 1000 watts, daily used of 3 hours
1000 = 1kW x 3 hrs = 3kwh
If the average cost of energy (not power) is t.00 per kwh for 30 days consumption, multiply:
30 x 3 = 90kwh x 5.00
450 pesos
In a series circuit - ___ is the same throughout but ___ differs.
Current
Voltage
In a parallel circuit, the __ is the same but the ___ differs.
voltage
current
Take note that in a ___ arrangement, all current loads cumulatively add. For instance, appliances and light loads connected to a parallel circuit has the same voltage imposed, but each load draws a different current according to its wattage rating.
Parallel
The power loss in the conductor wire is transformed into heat. COmparatively, a 1200 watts appliance rating has 10 amperes current flow on a 120 volts current supply compared to 5 amperes only on a 240 volts current supply. Therefore, it is certain to say that ___________.
bigger wire is required on a 120 volts that on a 240 volts current supply.
Here’s a proof:
1200/120 volt supply = 10 amperes
1200/240 volts supply = 5 amperes
A smaller diameter wire on a 240 volts current can safely carry more current in proportion with its weight than a larger diameter wire on a 120 volts supply current.
The ___ the circuit voltage the more economical the system will be.
Higher
1 HP =
746 watts
The owner of a 5kw electric motor irrigation pump, requested line connection from the electric cooperative. The owner was given an option to avail of either 120 or 240 volts service. What is the good choice if the circuit line has a resistance of .42 Ohms?
Voltage Drop formula :
Voltage Drop = V/Supply Volt = % of Voltage Drop
AWG
American Wire Gauge
Wire size and ampere capacity
Identify ampere capacity
no 14 (2mm2)
15 ampere
Wire size and ampere capacity
Identify ampere capacity
no 12 (3.5mm2)
20 ampere
Wire size and ampere capacity
Identify ampere capacity
no 10 (5.5mm2)
30 ampere
Wire size and ampere capacity
Identify ampere capacity
No. 8 (8mm2)
40 ampere
Wire size and ampere capacity
Identify ampere capacity
No 6
55 ampere
Wire size and ampere capacity
Identify ampere capacity
no 4
70 ampere
Wire size and ampere capacity
Identify ampere capacity
no. 0
125 ampere
___ insulators are those with extremely high resistance to current flow and moderate resistance to load resistor.
Good
Insulation is rated by voltage from 300 to 15000 volts. If the insulation used is above its specified rating, the ____ is high which might cause short circuit and arcing that may result to fire.
Risk of breakdown
Ordinary conductor wieres for buildings is normally rated at ___ or ___ volts
300 or 600 volts
__ are those electrical conductors 8..2 (AWG no 8) and smaller in sizes.
Wires
___ on the other hand are those which are larger than the wires.
Cables
2 types of cables or wires.
Stranded Wire or Solid WIre
Consists of a group of wires twisted to form a metallic string. THe circular mil area of a stranded wire is found by multiplying the circular mil area of each strand by the total number of strand.
Stranded Wire
__ is the term given to an insulated stranded wire.
Cord
The word __ that is equal to 1/1000 of an inch was used to describe or measure a rounded wire diameter. If a wiere has a diameter of one mil, it has a cross sectional area of one circular mil.
Mil
1 diameter mil
1 circular mil
mil=
1/1000”
Different types of Electric wire and cables.
60d C
1.60mm - 500mm2 solid and stranded
Ordinary building wire
TW oil resistant thermoplastic
Different types of Electric wire and cables.
75d C
1.6mm - 500mm2 solid and stranded
Building wire wet and dry location
THW oil, heat and moisture resistant thermoplastic
Different types of Electric wire and cables.
60dC
.6mm - .3mm2 solid and stranded
Fiture wire single conductor 2 conductor twister or parallel 3 conductor twisted
TF thermoplastic fixture wire
Different types of Electric wire and cables.
Copper
1.6mm - 500mm2
Bare overhead transmission line and for ground wire.
Bare copper wire (solid) and stranded.
Different types of Electric wire and cables.
1.50 mm - .39mm2 solid and stranded 2-3 and 4 conductors
General purpose
60 d C
Armored (BX) Cable
Different types of Electric wire and cables.
no 24 - no20
300 ohms tv wire
TV antenna wire
Different types of Electric wire and cables.
no 18 - no 2
105dC
Primary wire spark plug and battery cable
Automotive wire
60dC
no 14 - no 10
no 8 - no 1000 MCM
Power cable for aerial and duct 600 volts power cable for aerial duct and direct burial 600 voltz
Power cable
Different types of Electric wire and cables.
1.60 mm - 2.60mm2
2,3 and 4 conductors round or flat
For exposed or concealed works in air voilds in masonry blocks or tilewalls not exposed to excessive moisture or dampness. 600 volts
Non metallic sheathed cable type NM
Different types of Electric wire and cables.
22/3 conductors
Extension cord telephone equipment
Jacketed wire
Different types of Electric wire and cables.
1 pair thru 100 pairs
Interior communications and sound system
Intercom cable shileded or unshielded
Different types of Electric wire and cables.
60dC
No 6 - no 4/0
Arc welding machine
Welding cable
60dC
No 14 - no 1
2 and 3 conductors round connection.
For submersible pumps of deep wells
Submersible pump cable
Characteristics of Selected Insulated conductors for General Wiring:
KHW
75dC
FOr Dry and Wet location
Moisture and HEat resistant Rubber
Characteristics of Selected Insulated conductors for General Wiring:
T/TW
60dC
Dry Location
Dy and wet location
Thermoplastic moisture resistant thermoplastic
Characteristics of Selected Insulated conductors for General Wiring:
THHN
THW
90dC
75dC
Dry location, Dy and wet location
Thermoplastic heat resistant
Moisture and heat resistant thermoplastic
Characteristics of Selected Insulated conductors for General Wiring:
THWN
75dC
Dry and wet location
Moisture and heat resistant thermoplastic
Characteristics of Selected Insulated conductors for General Wiring:
XHHW
90dC
Dry location
Moisture and heat resistant cross linked thermosetting
Characteristics of Selected Insulated conductors for General Wiring:
SA
90C
Dry location
Silicon Asbestos
Characteristics of Selected Insulated conductors for General Wiring:
AVA
110dC
Dry location
Asbestos and varnish cambric
find how many circular mils are there in 21 stranded conductor:
Circular mil to Square millimiter
Circular mil x 0.0005067
MCM stands for
thousand circular mils
What is the equivalent size in square millimeter of a cable 250 MCM?
250 MCM = 250,000 circular mils
250,000 x .0005067
= 126.67 mm2
what is Bare Conductors for?
For Grounding
Type of Cables
is a fabricated assembly of insulated conductors enclosed in flexbile metal sheath. Armored cable is used both on exposed and concealed work.
Armored Cable (AC)
Type of Cables
is a factory assembled cable of one or more conductors each individually insulated and enclosed in a metallic sheath of interlocking tape of a smooth or corrugated tube This type of cable is especially used for service feeders, branch circuit and for indoor or outdoor work.
Metal Clad Cable
Metal Clad Cable (MC)
Type of Cables
is a factory asembly of one or more conductors insulated wit ha highly compressed refractory mineral insulation enclosed in a liquid and gas tight continuous copper sheath. This type of cable is used in dry, wet or continuously moist location as service feeders or branch circuit.
Miniral insulated cable MI
Mineral insulated Cable (MI)
Type of Cables
Is also a factory assembly of two or more insulated conductors having a moisture resistant, flame retardant, and non-metallic material outer sheath. This type is used specifically for one or two family dwellings not exceeding 3 storey buildings.
Non metallic Sheated cable (NM)
Non-MEtallic Sheathed cable (NM)
Type of Cables
This type of cable is a factory assembly of two or more insulated conductors in an extruded core of moisture resistant and flame retardant material covered within an overlapping spiral metal tape. This type is used in hazardous locations and in cable trays or in raceways.
Shielded Non-Metallic Sheathed Cable (SNM)
Shielded Non-Metallic Sheathed Cable (SNM)
Types of Cables
Is a moisture resistant cable used for underground conections including direct burial in the ground as feeder or branch circuit.
Underground Feeder and Branch Circuit Cable (UF)
Underground Feeder and Branch Circuit Cable (UF)
Type of Cables
is of the types SE and USE. A single or multi conductor asembly provided or without an overall covering primarily used for service wire.
Service Entrance Cable
Service Entrance Cable
Types of Cables
This is a factory assembled two or more insulated conductors with or without associated bare or covered grounding under a metallic sheath. This is sued for installation in cable trays, raceways or where it is supported by messenger wire.
Power and Control Tray Cable (TC)
Power and Control Tray Cable
Types of Cables
is an assembly of parallel conductors formed integrally with an insulating material web designed specially for field installation in metal surface or raceways.
Flat Cable Assemblies (FC)
Types of Cables
consists of three or more flat copper conductor placed edge to edge separated and enclosed within an insulating assembly. This type of cable is used for general purposes such as: appliance branch circuits, and for individual branch circuits, esp in hard smooth continuous floor surfaces and the like.
Flat conductor cable (FCC)
Types of cables
is a single or multi conductor solid dielectric insulated cable rated at 2000 volts or higher This type isused for power system up to 35,000 volts.
Medium Voltage cable (MV cable)
is defined as the ability of the wire or conductor to carry current without overheating. Conductor resistance to current flow, generaly not ony heat but also contribute to the voltage drop,
Ampacity
___ is equal to the components resistance times the current squared.
Power Loss
Conductor size and rating shall have sufficient ampacity to carry load, They shall have adequate mechanical strength and shall not be less than the rating of the branch circuit and not less the ___.
Maimum load to be served
___ is determine by the maximum operating temperature that its insulation can withsatand continuously without heating. Current flow and conductor’s resistance normally generates heat.
Conductors Ampacity
__ refers to either enclosed or open condition on which the wire is placed.
Environtment
____ or ability of the conductor to carry load, increases as the sizes of conductor increases. If more than 3 conductors are inserted into a conduit, the temperature also increases and it requires derating of the conductors ampacity.
Ampacity
60dC up to ___ AWG copper wire
no 8
75d C for bigger than ___ AWG copper wire
75dC
means that, the full amount of allowable ampacity, is reduced to a certain percentage due to the environmental condition it is exposed of and the number of wires placed inside the conduit.
Derating of Conductors Ampacity
___ are channels or wiring accessories so designed for holdign wires, cables or busbards that are either made of metal, plastic or any insulating mediums.
Raceways
Common types of raceways for household wiring
The Conduits
The connectors and other accessories
__ is the most common electrical raceways used in all types of construction.
Conduit Pipe
Types of conduit materials:
Metallic suchas steel pipes or aluminum
Non-metallic such as plastic and the like
__ is a metal sleeve usually made of copper that is slipped over and secured to the butted ends of conductors in making a joint.
Connector
Connector is otherwise called ___.
Splicing sleeve
EMT
Electrical metallic tubing (EMT)
Intermediate metal conduit (IMC) is a steel tubing heavier than EMT but lighter than RMC. It may be threaded. Electrical metallic tubing (EMT), sometimes called thin-wall, is commonly used instead of galvanized rigid conduit (GRC), as it is less costly and lighter than GRC.
Stamped steel
Malleable Iron
C CLamp
Pipe clamps
U Bolt