Special Purpose Electrical Switches

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Special Purpose Electrical Switches

• W. C.Buster Hounshell
• Spring 2002

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Double Switches

• A double switch has two switch levers in a single
  housing
• It is used to control two light fixtures or
  appliances from the same switch box.

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Double Switches

• Single-circuit wiring Three black wires are
  attached to the switch
• The black feed wire bringing power into the box
  is connected to the side of the switch that has a
  connecting tab

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Single-circuit wiring

• The wires carrying power out to the light
  fixtures or appliances are connected to the side
  of the switch that does not have a connecting tab
• The white neutral wires are connected together
  with a wire connector

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Double SwitchSeparate-circuit wiring

• Four black wires are attached to the switch
• Feed wires from the power source are attached to
  the side of switch that has a connecting tab, and
  the connecting tab is removed

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Double SwitchSeparate-circuit wiring

• Wires carrying power from the switch to light
  fixtures or appliances are connected to the side
  of the switch that does not have a connecting tab
• White neutral wires are connected together with a
  wire connector

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Removing the connecting tab

• Remove the connecting tab on a double switch when
  wired in a separate-circuit installation
• The tab can be removed with needle- nose pliers
  or a screwdriver

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Pilot-light Switches

• A pilot-light switch has a built-in bulb that
  glows when power flows through the switch to a
  light fixture or appliance
• Pilot- light switches often are installed for
  convenience if a light fixture or appliance
  cannot be seen from the switch location

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Pilot-light Switches

• A pilot-light switch requires a neutral wire
  connection
• A switch box that contains a single two- wire
  cable
• Has only hot wires and cannot be fitted with a
  pilot- light switch

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Switch/receptacles

• A switch/receptacle combines a grounded
  receptacle with a single-pole wall switch
• In a room that does not have enough wall
  receptacles, electrical service can be improved
  by replacing a single-pole switch with a
  switch/receptacle

11
Timer Switches

• Timer switches have an electrically powered
  control dial that can be set to turn lights on
  and off automatically once each day
• They are commonly used to control outdoor light
  fixtures

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Time-delay Switches

• A time-delay switch has a spring-driven dial that
  is wound by hand
• The dial can be set to turn off a light fixture
  after a delay ranging from I to 60 minutes
• Time-delay switches often are used for exhaust
  fans, electric space heaters, vent fans, and heat
  lamps

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Automatic Switches

• An automatic switch uses a narrow infrared
• beam to detect movement
• When a hand passes within a few inches of the
  beam, an electronic signal turns the switch on or
  off
• Some automatic switches have a manual dimming
  feature

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Automatic Switches

• Automatic switches can be installed wherever a
  standard single-pole switch is used
• Automatic switches are especially convenient for
  children and persons with disabilities.

• Automatic switches require no neutral wire
  connections
• For this reason, an automatic switch can be
  installed in a switch box containing either one
  or two cables
• The wire leads on the switch are connected to
  hot circuit wires with wire connectors

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Motion-sensor Security Switches

• A motion-sensor switch uses a wide-angle infra-
  red beam to detect movement over a large area
• Turns on a light fixture automatically
• A time-delay feature turns off lights after
  movement stops

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Motion-sensor Security Switches

• Most motion-sensor switches have an override
  feature that allows the switch to be operated
  manually
• Better switches include adjustable sensitivity
  control and a
• Variable time-delay shutoff control.

• Motion-sensor switches require no neutral wire
  connections
• They can be installed in switch boxes containing
  either one or two cables
• The wire leads on the switch are connected to
  hot circuit wires with wire connectors

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Programmable Switches

• Programmable switches represent the latest in
  switch design
• They have digital controls and
• Can provide four on-off cycles each day

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Programmable Switches

• Programmable switches frequently are used to
  provide security when a homeowner is absent
• Programmed lighting is a proven crime deter- rent
• For best protection, programmable switches should
  be set to a random on-off pattern.

• Programmable switches require no neutral wire
  connections
• They can be installed in switch boxes containing
  either one or two cables
• The wire leads on the switch are connected to hot
  circuit wires with wire connectors

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Dimmer Switches

• Any standard single-pole switch can be replaced
  with a dimmer, as long as the switch is of
  adequate size. Dimmer switches have larger
  bodies that standard switches. They also
  generate a small amount of heat that must
  dissipate. For these reasons, dimmers should not
  be installed in undersized electrical boxes or in
  boxes that are crowded with circuit wires.
  Always follow the manufacturers specifications
  for installation.

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Dimmer Switches

• Dial-type dimmer is the most common style.
  Rotating the dial changes the light intensity.

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Dimmer Switches

• Slide-action dimmer has an illuminated face that
  makes the switch easy to locate in the dark.

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Dimmer Switches

• Automatic dimmer has an electronic sensor that
  adjusts the light fixture to compensate for the
  changing levels of natural light. An automatic
  dimmer also can be operated manually.