Topic 2 Reading Blueprints and Drawings

SCO 2.14

SCO

• Students will be expected to:– 2.14 read and interpret electrical drawings [1.401]

[1.402][1.403][2.401][2.402]

Why?

• The purpose of this outcome is to provide an introduction to the basic electrical symbols used on floor plans.

• Electrical drawings are used by carpenters to build the structures needed to hold the electrical devices.

• They are used by electricians to plan circuits and wiring runs, and to place electrical boxes and wires for the electrical rough-ins

Electrical Devices

Switches : 1. A single-pole switch is one switch that

controls one light or a group of light fixtures. It has two screw terminals on the side plus one green screw for the ground wire.

2. A three-way switch has two switches that control the same fixture or fixtures. It has two like colored screws, one darker-colored screw, and one green screw for the ground wire.

Electrical Devices - Switch

Electrical Device Symbols

Electrical Devices - Receptacle

• Outlets • A duplex outlet, your standard outlet, is called a

duplex because it has two places to plug into. • Non-grounded outlets are duplex outlets

without the third hole below the two vertical slots. This outlet doesn't have a ground wire running to it. If you have any equipment that requires a ground, it is best to get the outlet grounded than to use one of the adaptors.

Duplex Receptacle

Non-grounded Receptacle

• A GFCI or Ground Fault Circuit Interrupter is most easily recognized by the two buttons in the middle of the outlet.

• It is used wherever water is nearby - kitchen, bathroom, outside outlets, and in unfinished basements, due to its sensitive nature to power surges.

Ground Fault Circuit Interrupter

• A switched outlet is a duplex outlet that is controlled by a switch or dimmer. In most cases only one-half of the outlet is switched.

• A single outlet, this outlet has only one spot to plug something into it. It is commonly used where a dedicated piece of equipment will be used near water. A clothes washer is the most common use in a residential home.

Switched Receptacle

Single Receptacle

Wiring Plan• This plan for wiring a kitchen includes a 15-amp circuit for lights, some controlled by three-way switches.• A 20-amp refrigerator circuit has been added, as well as two 20-amp small-appliance circuits and a 20-amp circuit for the dishwasher and garbage disposer. • The range has its own circuit.

Assignment

• Given an Electrical Drawing , examine it and make a list of the:– Locations and number of 120 volt receptacles– Locations and number of lights– Locations and number of switches and the devices

they control, distinguishing single, and three-way switches