Planning Electrical Circuits

1
Planning Electrical Circuits

• Original by Ryan Talton
• Modified by Georgia Agriculture Education
  Curriculum Office June 2004

2
Planning for the SEP and/or Sub panel

• SEP should always be located near the service
  entrance
• Might want to place the SEP close to large
  appliances and equipment that will require most
  electricity
• Should be accessible at all times
• Try to anticipate future needs when finding site
• Never have SEP in clothes closet or bathroom
• Box Should be installed 40-48 inches above floor
  level
• Can be installed flush or surface mount.

3
Outlet Spacing

• Overhead Lighting
• May be placed in discretion of owner
• In single overhead light should be in center of
  room
• Wall Outlets (Receptacles)
• No point on a unbroken wall measures greater than
  6 feet
• This includes wall space of 2 feet or more in
  width
• Unbroken by doorways, fireplace, etc.
• Most receptacles should be 12 and 16 inches above
  floor level

4
Kitchen Countertop Outlets (Receptacles)

• Should always be installed at each counterpace no
  wider than 12 inches
• Should be installed within 24 inches of each
  other on countertops
• No more than 18 inches above countertops
• All kitchen Receptacles should be GFCI protected
• We will learn more about this later

5
Closet and Storage lighting Outlets

• Surface mounted incandescent fixtures should be
  located 12 inches between fixtures and storage
  area
• Surface mounted fluorescent- may be mounted
  within 6 inches of storage area
• If recessed- both can be 6 inches from storage
  area.

6
Planning Small Appliance Branch Circuits

• Determine the number of circuits necessary to
  meet wiring plan requirements
• Larger homes may call for more circuits

7
What is a Small Appliance Branch Circuit?

• Generally supply power to kitchen counter top
  surfaces and dining room areas where small
  appliances are commonly used
• Coffee makers, fry pans, blenders, toaster ovens,
  waffle irons

8
Planning General Purpose Branch Circuits

• Make up the largest portion of the home wiring
  system
• Include all ceiling and wall mounted lighting
  outlets and most receptacles
• Not ones for a specific purpose
• All circuits originate in SEP

9
How do I Calculate the Required Number of General
Purpose Circuits?

• General Rule
• One General Purpose Circuit for every 500 square
  feet
• 2500 sq ft house 5 gpc
• What about a house that is 2240 sq ft
• 2240/5004.48
• This equals 4.48 gpc
• Always go to the next highest number when
  figuring the number of circuits
• So 2240/5005 gpc
• Only figure the amount of heated space
• Not garage or porch space

10
Balancing a Load

• Why is it important to balance a load?
• General rules are
• 10 outlets per 15 amp circuit General Purpose
• 13 outlets per 20 amp circuit General Purpose
• If the above 10 or 13, add another circuit

11
Example Problem

• 40
• 50
• Determine the number of general purpose circuits.
  (1 circuit for every 500)

12
Answer to Example 1

• 40x502000 sq ft.
• 2000/5004 GPC

13
Example 2

• 45
• 65
• 20 amp GPC
• 75 outlets

14
Answer to example 2

• 45 x 652925sq ft
• 2925/5005.85
• Need 6 circuits
• 75 outlets / 6 circuits 12.5
• Do we need to add another circuit?

15
Example 3

• 35
• Two story house
• 15 amp GP
• 55 96 outlets

16
answer

• 35 x 551925 sq ft
• 1925 x 23850 sq ft for both floors
• 3850 / 500 7.7
• Need 8 circuits
• 96 outlets / 8 12 outlets per circuit
• Do we need another circuit
• Add 2 circuits
• Need 10 general purpose circuits which would make
  it 9.6 outlets per circuit