Electrical Planning

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Electrical Planning 3
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Electrical Conductors
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Electrical Conductors

• Wires used to conduct electricity are classified
  by
• the type of wire material
• the insulation material
• and the wire size

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Electrical Conductors

• The size of the wire used in a circuit depends on
  the current to be carried by the circuit

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Electrical Conductors

• Although the meter voltage is 120V and 241V
• wiring resistance reduces the voltage at the
  receptacles
• to approximately
• 110Va
• and 220V

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Electrical Wire Sizing

• The exact size depends on the capacity of the
  service panel

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Electrical Wire Sizing

• Sizes 6 through 2/0 are used for 240-vold (240V)
  service entrance and circuits
• Sizes 10 through 14 are used for 120V and 240V
  lighting and small appliance circuits
• Sizes 16 and 18 are used for low voltage items
  such as thermostats and doorbells

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Electrical Wire Sizing

• A low-voltage switching system may be used to
  turn on or off
• any fixture
• Appliance
• or light
• Because of the low voltage
• extremely small wires are used to hook up the
  switch to the fixture

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Electrical Wire Sizing

• Wire size is critical
• If a wire is too small for the current applied
• excessive resistance (overload) can result
• This may cause the insulation to overheat and
  break down
• causing a potential fire hazard

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Electrical Wire Sizing

• When selecting or preparing to use appliances
• it is important to check the UL (Underwriter's
  Laboratories) ratings
• to learn the proper wiring requirements

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Electrical Wire Types

• Aluminum wire is lighter and less expensive than
  copper
• but many codes apply stricter rules to the use of
  aluminum for residential work

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Electrical Wire Types

• Insulation is available in flexible metal armored
  or nonmetal sheathed worm
• For underground or exterior exposed wiring
• wires must be encased in rigid or flexible metal
  or PVC (plastic) conduits