electrical wiring presentation

1. Basic Electrical WiringBasic Electrical Wiring
Grimsby SecondaryGrimsby Secondary
SchoolSchool

2. Electrical SafetyElectrical Safety
"Shocking Statistics“"Shocking Statistics“
 There are approximately 290 accidental electrocutions each year.There are approximately 290 accidental electrocutions each year.
 An additional 800 people die in fires caused by faulty electricalAn additional 800 people die in fires caused by faulty electrical
systems every year.systems every year.
 Thousands are shocked and burned as the result of accidentalThousands are shocked and burned as the result of accidental
contact with electricity every year.contact with electricity every year.
 An estimated $1.2 billion in property damage occurs each year dueAn estimated $1.2 billion in property damage occurs each year due
to faulty use of electricity.to faulty use of electricity.

3. ElectricityElectricity
 Electricity is the flow of electrons in aElectricity is the flow of electrons in a
conductor.conductor.
 The electrons must have a path to andThe electrons must have a path to and
from its source.from its source.
 This path is called a circuit.This path is called a circuit.

4. ElectricityElectricity
 Various electrical devices are used as aVarious electrical devices are used as a
part of the circuit.part of the circuit.
 These devices are used for a variety ofThese devices are used for a variety of
activities, such as turning the electricity offactivities, such as turning the electricity off
and on, providing electricity to variousand on, providing electricity to various
lights or appliances, etc.lights or appliances, etc.

5. Types of Electrical CurrentsTypes of Electrical Currents
 Electrical current comes in two forms:Electrical current comes in two forms:
– Direct current (DC)Direct current (DC)
Flows in only one direction.Flows in only one direction.
It is usually generated by battery-base electricalIt is usually generated by battery-base electrical
systems and used in the electrical systems ofsystems and used in the electrical systems of
internal combustion engines or flashlight batteries.internal combustion engines or flashlight batteries.
– Alternating current (AC)Alternating current (AC)
Reverses the direction of flow of current manyReverses the direction of flow of current many
times each second.times each second.
AC is the type used in homes, factories, etc.AC is the type used in homes, factories, etc.

6. Electrical ServiceElectrical Service
 Service is provided to homes, businessesService is provided to homes, businesses
and other small users of electricity byand other small users of electricity by
three wires from a utility pole.three wires from a utility pole.
 Two of the wires are “hot,” each carryingTwo of the wires are “hot,” each carrying
120 volts.120 volts.
 The other wire is “neutral,” and providesThe other wire is “neutral,” and provides
the return path for electricity.the return path for electricity.

7. Electrical Service (cont.)Electrical Service (cont.)
 These wires are connected to a serviceThese wires are connected to a service
entrance, which is where the electricityentrance, which is where the electricity
enters a building.enters a building.
 A meter is used in the service entrance toA meter is used in the service entrance to
measure the amount of electricity beingmeasure the amount of electricity being
used.used.

8. Electrical Service (cont.)Electrical Service (cont.)
 The service entrance is grounded with aThe service entrance is grounded with a
wire connected to a ground rod drivenwire connected to a ground rod driven
several feet into the ground.several feet into the ground.
 It is needed to provide a return path to theIt is needed to provide a return path to the
ground and to carry away stray electricalground and to carry away stray electrical
current out of the system.current out of the system.

9. Service PanelService Panel
 Follows the meter.Follows the meter.
 It houses the circuitIt houses the circuit
breakers for thebreakers for the
system and is used tosystem and is used to
distribute the power todistribute the power to
individual circuitsindividual circuits
throughout thethroughout the
system.system.

10. OvercurrentOvercurrent
 When a circuit uses too much electricity, anWhen a circuit uses too much electricity, an
overcurrent causes a circuit breaker to trip,overcurrent causes a circuit breaker to trip,
shutting down the power to that circuit.shutting down the power to that circuit.
 The excessive heat caused by an overcurrentThe excessive heat caused by an overcurrent
condition may burn or damage a conductor’scondition may burn or damage a conductor’s
insulation and cause a fire.insulation and cause a fire.
 A circuit breaker is a heat-sensitive switch,A circuit breaker is a heat-sensitive switch,
which automatically trips when electricitywhich automatically trips when electricity
demand is too great which causes thedemand is too great which causes the
temperature in the conductor to get too hot.temperature in the conductor to get too hot.

11. Amps Volts WattsAmps Volts Watts
The following relationship existsThe following relationship exists
betweenbetween Amps, VoltsAmps, Volts andand WattsWatts..
Amperes are a measure of the rate of flow
of electricity in a conductor.
Volts are a measure of electrical pressure.
 Watts are a measure of the amount of
energy or work that can be done by
amperes and volts.

12. What symbols are used in drawing variousWhat symbols are used in drawing various
electrical devices?electrical devices?
In order to successfully draw a wiring circuitIn order to successfully draw a wiring circuit
on paper, one needs to use various symbolson paper, one needs to use various symbols
that represent the equipment.that represent the equipment.
Identify and draw various symbols
used in drawing wiring diagrams or
schematics.

13. Cable TypesCable Types

14. Cable TypesCable Types
One is 14/2 with ground, which has oneOne is 14/2 with ground, which has one
black conductor, one white conductor, andblack conductor, one white conductor, and
a bare ground conductor.a bare ground conductor.

15. Cable Types (cont.)Cable Types (cont.)
A third type of cable is 14/3 with ground,A third type of cable is 14/3 with ground,
which has one black conductor, one whitewhich has one black conductor, one white
conductor, one red conductor, and oneconductor, one red conductor, and one
bare ground conductor.bare ground conductor.

16. Additional symbols are usedAdditional symbols are used
to identify terminals andto identify terminals and
indicate if wires are spliced orindicate if wires are spliced or
just crossing over.just crossing over.

17. Symbols (cont.)Symbols (cont.)

18. Symbols (cont.)Symbols (cont.)
MARRETTE
External cap made of tough, durable polypropylene.
Threaded entry helps guide large wire bundles into the
spring chamber. Unique copper-coated spring helps
resist corrosion. Approved for circuits up to 600 V, and
lighting fixtures and sings up to 1,000 V.

19. DiagrammingDiagramming
Generally, black and red conductorsGenerally, black and red conductors
carry “hot” power or current from thecarry “hot” power or current from the
source to the devices within thesource to the devices within the
circuit.circuit.
 The white conductor is always used toThe white conductor is always used to
carry the current back to the source.carry the current back to the source.

20. Two and Three wireTwo and Three wire

21. How to wire a receptacleHow to wire a receptacle
All receptacles should be wired such that
the hot or live (black) lead is connected to
a specific side of the outlet, and the neutral
(white) lead to the other.