Chapter 29 Electrical Plans

Objectives Describe an electrical plan and identify its features. Identify typical electrical symbols found on a residential electrical plan. Draw an electrical plan for a residential structure using manual drafting techniques. Draw an electrical plan for a residential structure using CADD.

Electrical Plan Electrical plan shows location and type of electrical equipment to be used Plan view section Usually traced from floor plan Shows meter distribution panel, outlets, switches, and special features Identifies number and types of circuits

Required Information Number, type of circuits Service entrance capacity Meter, distribution panel location Location, placement, type of switches Location, type of lighting fixtures Special electrical equipment Number, type of circuits

Required Information Electrical fixture schedule Symbols, legends, and notes Required amperage rating of service is shown beside distribution panel

Common Electrical Symbols

Service Entrance Locate service entrance equipment close to service drop Main breaker should be close to meter Locate service entrance close to largest energy users Larger loads require larger conductors Shorter runs reduce voltage drops

Employability Negotiation Process of coming to agreement on an issue that requires all parties to give and take a little to achieve intended result Begins with trying to understand the other person’s interests Together try to reach possible solutions that meet mutual concerns

Meters Outside location is preferred, but meter can be located inside or outside Smart meters can be read remotely by utility company

Switches Number and placement of switches is related to number of lighting fixtures, switched outlets, and equipment Select logical location for each switch Use proper symbols to show type of switch

Switches On electrical plan, switches are shown connected to fixtures, appliances, and outlets they operate Thin, curved hidden line or centerline shows connection Lines do not represent actual wiring, but only elements connected Use SPLINE or POLYLINE in CADD

Receptacle Outlets Place outlets every 6' to 8' along all walls Outlets are usually 120-volt duplex Some duplex outlets may be split-wired Receptacle outlets should be grounded or GFCI to prevent shock

Receptacle Outlets Receptacle outlets may be switched or always “hot” Consider furniture arrangement when locating switches and outlets

Special-Purpose Outlets Special-purpose receptacle outlets may have one or several receptacles Unique symbols should be identified in a legend

Traditional Lighting Two types of lights have been commonly used Incandescent light Screw-in bulb Fluorescent light Tube

Energy-Efficient Alternatives Compact fluorescent lightbulbs (CFLs) Contain mercury Light-emitting diode (LED) lights Multiple colors; many uses Electronic-stimulated luminescence (ESL) lights Up to 70% more energy-efficient than incandescent bulbs

Lighting Fixtures Trend is toward more freestanding lamps and fewer ceiling-mounted fixtures Recessed lighting fixtures for hallways, foyers, or special emphasis Track lighting is another option

Exterior Lighting Exterior light fixtures should be rated for exterior applications Plan adequate lighting for: Walks Drives Porches Patios Other outside areas

Lighting Fixture Schedule Use proper symbol for each lighting fixture at actual location Include lighting fixture schedule in electrical plan

Green Architecture Phasing out the incandescent lightbulb In United States, higher-energy bulbs were restricted first, with phase-out to be completed in 2014 Some bulbs are exempt from restrictions, such as appliance lamps Keep up-to-date with new technologies and incorporate them into designs when possible

Other Devices Telephone jacks Intercom system Home security devices TV antenna jack Cable or satellite TV jack Door chimes Audio outlets

Branch Circuits Electrical plan indicates number and type of branch circuits Circuit data is generally shown as note, chart, or diagram on electrical plan Number of lighting, small-appliance, and individual circuits should be listed

Manual Drafting: Electrical Plan Trace exterior and interior walls and major appliances from floor plan. Locate meter and distribution panel. Indicate voltage and amperage rating. Locate telephone junction box and home security or automation wiring enclosure. Check building code requirements.

Manual Drafting: Electrical Plan 3. Show all receptacle outlets using proper symbols. 4. Locate all ceiling and wall lighting outlets. Use standard lighting symbols. 5. Show all special-purpose outlets and fixtures. 6. Locate switches and connect them to outlets and lighting fixtures they operate.

Manual Drafting: Electrical Plan 7. Add lighting fixture schedule and symbol legend, if needed. 8. Note number and type of circuits required. 9. Letter all other notes and title, scale, and sheet number. 10. Check drawing for accuracy and completeness.

Residential Electrical Plan

CADD: Electrical Plan If electrical plan is to be a separate file, open floor plan drawing and save it with new name. If combining electrical plan with floor plan, create set of layers specifically for electrical plan and lock or freeze all other layers.

CADD: Electrical Plan 2. Locate meter and distribution panel. Indicate voltage and amperage rating. Locate telephone junction box and home security or automation wiring enclosure. Double-check local building codes. 3. Insert symbols for receptacle outlets, placing them on electrical symbols layer. Indicate receptacle types.

CADD: Electrical Plan 4. Insert symbols for ceiling and wall lighting outlets on electrical symbols layer. 5. Insert symbols for special-purpose outlets and fixtures on the electrical symbols layer. 6. Insert symbols for switches on electrical symbols layer.

CADD: Electrical Plan Connect switches to outlets and lighting fixtures they operate. Use hidden or centerline linetype with SPLINE command or Spline option of POLYLINE command. Place these lines on separate layer to achieve proper line width when plotting. Add lighting fixture schedule and symbol legend, if needed.

CADD Drafting Procedure 9. Add note indicating number and type of required circuits. Create other notes and add title, scale, and sheet number. Place specific notes on their own layer. 10. Check drawing for accuracy and completeness.

Residential Electrical Plan Drawn Using CADD