Transcript Residential Wiring Facts

Residential Wiring Facts
Part 1 Power Generation and Transmission
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1.1) During electricity transmission the voltage is
stepped up to as much as 765,000 VAC so that
current through the power grid is dropped extremely low
to minimize energy loss.
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1.2) When power is needed in your neighborhood or,
specifically, your home step-down transformers are
used to reduce the amount of voltage available for use
from the 765,000 VAC used to transmit electricity
through the power grid to 120 VAC you use in you day to
day appliances and electrical devices.
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1.3) Electrical energy, for large usages like cities
and towns, can be created by many of the forms
discussed earlier. Here in the Denver Metro
area electricity generating turbines are powered
by steam created by burning coal.
Part 2 Home Usage and Grounding
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2.1) Appliances in your home use either 240 or 120 VAC.
2.2) All houses are equipped with a Grounding Rod, a
metal rod driven into the earth, that is connected to the
house’s electrical service panel to provide a pathway of
conduction that will allow over load of current to be sent
directly to the ground. This keeps your house safe from
high voltages like lightening or power grid overloads.
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2.3) The house service panel (aka Circuit-Breaker
Panel) is the main connection between the house and
the power grid.
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2.4) The service panel is supplied with two 120 VAC
lines and a single neutral line from the setup down
transformers on the power grid.
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2.5) In the case of a clothes dryer or water heater the
two 120 VAC lines are connected in parallel to create
240 VAC.
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2.6) In all case a neutral (usually white ) wire
which is used to complete the circuit and a
green (or bare) wire which is used to connect
the circuit to ground are supplied along with the
“hot” single or double wire in the same wire run.
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2.7) Each and every single component of an
electrical circuit must be grounded to all the
other parts to produce one cohesive system that
will handle overload and short circuits.
Part 3 Electrical Schematics and Wiring Diagrams
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3.1) An electrical schematic shows how
electricity flows in a circuit, where as a
wiring diagram show how electrical
components are wired together.
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3.2) A wiring diagram must show all
circuit components and connections.
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3.3) In a wiring diagram symbols are used
to represent circuit components.
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3.4) In a wiring diagram each component
must show the termination of all wires and
their color.
Part 4 Breakers and Circuit Run
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4.1) A circuit run is a circuit receiving power from the
service panel that is protected by its own isolated breaker
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4.3) A circuit breaker is a component that will
automatically disconnect if the current load in the circuit
run becomes higher than its rated value.
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4.2) Circuit breakers are usually valued at 15 or 20 amps
and can protect approximately 8 to 10 receptacles in a
single circuit run.
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4.5) An End Run receptacle connection describes a
receptacle that terminates the end of a circuit run and
will only have wire feeding into the receptacle.
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4.6) A Middle Run receptacle connection describes a
receptacle that has power running into it from a previous
receptacle and then out from it to another receptacle
down the line. Each middle run receptacle will have wire
feeding in and out from it.
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4.7) A Circuit run is composed of a series of several
connections of receptacles, switches and/or lights
terminating at the last “End Run” receptacle.
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4.8) A load first run circuit brings power into the outlet or
light receptacle box then runs a two wire romex to the
switch if necessary.
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4.9) A switch first run circuit brings power into the switch
receptacle box and then daisy changes power to each
consecutive receptacle box.
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4.10) A 3-way circuit is used to allow a circuit to be
controlled by two different switches in different locations
(i.e. a stairway).
part 5 Circuit components and connections
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5.1) Wire Connectors (aka wire nuts) are
used to quickly connect multiple wires
without soldering.
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5.2) Always make sure the wire insulation
covers the wire all the way up into the wire
nut (so no bare wire is showing).
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5.2) Electrical tape should not be the actual
connection devise but a backup to prevent
possible short circuits. A wire nut, solder, or
termination screws should always hold wire
together not tape.
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5.3) Pigtails are short lengths of wire 4 or 5
inches long, used when two or more wire need
to connect to a termination screw.
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5.4) Red wire nuts should hold up to 4 or 5
wires (depends on gauge; 4) 12-gauge or 5) 14gauge)
Yellow wire nuts hold up to 3 or 4 wires
Orange wire nuts hold up to 2 or 3 wires
color
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Red
Yellow
Orange
12 guage
14 guage
2-4 wires
2-3 wires
2 wires
3-5 wires
2-4 wires
2-3 wires
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5.5) Switches, outlets and other residential wiring
components always have termination screws for the wire
to connect to the component. Some newer components
come with “push connectors” to make things go faster.
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5.6) A wire that connects to a component should be
stripped back about 3/4 of an inch and a small loop is
made that will connect to the termination screw in a
clockwise direction. (clockwise so the wire will tighten
with the screw).
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5.7) Hot wire (usually black) is terminated to the
brass screws and neutral wire (usually white) is
terminated to the silver screws.
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5.8) Lineman’s pliers are used to twist together
the wire ends to be connected by a wire nut.
After the wire nut is secure use tape to enclose
the connection to minimize to possibility of a
short circuit or moister at the connection.
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5.9) A 3-way switch is also known as a
single pole double throw (SPDT) switch.
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5.10) A dimmer switch is also known as a
potentiometer or a variable resistor.
Part 6 stripping wire
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6.1) Cut back the romex sheathing about 3 inches and
snip off the hanging sheathing with a diagonal cutter or
lineman’s pliers.
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6.2) Use a stripping tool to accurately cut off the
individual wire insulation without cutting into the wire
itself.
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6.3) Stripping tools often need to be adjusted for certain
wire gauges. See information for each type of stripping
tool before use.
part 7 Connecting Romex and
Conduit to boxes
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7.1) Romex is the commercial title for sheathed wire
(sets of wire wrapped together with an outer covering).
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7.1) No electrical connections should be made outside of
and electrical box.
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7.2) Romex wire should be snuggly connected to the
electrical box using a saddle clamp.
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7.3) The Romex feed wire should extend out at least 6
inches from the receptacle box to allow good
connections to be made and for future rewiring.
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7.4) Rigid or metal flexible conduit is snuggly connected
to the electrical box using a knockout clamp or screw
connector through a knockout then held tight by a
locknut in the inside.
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7.5) Many newer plastic electrical boxes come with quick
connect clamps that are directly manufactured into the
electrical box. Push in the romex wire and it won’t come
back out.
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7.6) When working with plastic electrical boxes always
remember to ground the receptacle directly (a pigtail to
the receptacle box is not necessary).
part 10 testing components
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10.1) Remember to always disconnect power before
testing a circuit.
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10.2) If a connection is turned on and does not operation
correctly a Multimeter set to continuity testing should be
used to isolate the connection problem.
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10.3) Always check cables, romex and wire installation
for cracks or splits before you uses them.
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How is electrical energy created for large usages like
cities and towns?
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What does a switch look like in a wiring diagram?… or in
a schematic?
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Which symbol …
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Which symbol shows wires being connected with a wire
nut?