The document outlines electrical design principles focusing on branch circuit, device and equipment, and conductor requirements. It details various types of branch circuits, including individual, general purpose, life safety, and critical circuits, along with standards for switches, receptacles, and conductor materials. Additionally, it emphasizes the importance of proper enclosure for wiring and connections to ensure safety and compliance with regulations.

1. [ ELECTRICAL DESIGN PRINCIPLES ]
( ENGINEERING UTILITIES 1 )

2. [ TOPICS ]
1. BRANCH CIRCUIT REQUIREMENT
2. DEVICE AND EQUIPMENT
REQUIREMENT
3. ELECTRICAL MATERIAL
REQUIREMENT
 CONDUCTOR REQUIREMENT
 CABLE, RACEWAY,
ENCLOSURE REQUIREMENTS

3. [ BRANCH CIRCUIT
REQUIREMENTS ]
TYPES OF BRANCH CIRCUIT
 INDIVIDUAL
 GENERAL PURPOSE
 APPLIANCE
 MULTIWIRE
 LIFE SAFETY
 CRITICAL

4. INDIVIDUAL
BRANCH CIRCUIT
SERVES ONE
RECEPTACLE OR PIECE
OF EQUIPMENT SUCH AS
FOR A RANGE, CLOTHES
DRYER, LARGE COPY
MACHINE, OR OTHER
PIECE OF MACHINERY.

5. GENERAL
PURPOSE
BRANCH CIRCUIT
SUPPLIES TWO
OR MORE RECEPTACLES
OR OUTLETS FOR
LIGHTING AND
APPLIANCES

6. APPLIANCE
BRANCH CIRCUIT
SUPPLIES TO ONE
OR MORE OUTLETS FOR
THE PURPOSE OF
CONNECTING APPLIANCE

7. MULTIWIRE
BRANCH CIRCUIT
CONSISTING OF TWO OR MORE
UNDERGROUNDED (HOT) CONDUCTOR
HAVING A VOLTAGE BETWEEN THEM
AND A COMMON NEUTRAL
(GROUNDED) CONDUCTOR THAT IS
SHARED BETWEEN THE
UNDERGROUNDED CONDUCTORS SUCH
AS IN A 120/240 V THREE-WIRE CIRCUIT.

8. LIFE SAFETY
BRANCH CIRCUIT
AN EMERGENCY SYSTEM OF
FEEDERS AND BRANCH CIRCUIT THAT
PROVIDES ADEQUATE POWER TO
PATIENTS AND PERSONNEL. IT MUST
AUTOMATICALLY CONNECT TO AN
ALTERNATE POWER SOURCE SUCH AS A
GENERATOR WHEN THE NORMAL
POWER SOURCE IS INTERRUPTED.

9. CRITICAL
BRANCH CIRCUIT
AN EMERGENCY SYSTEM OF FEEDERS
AND BRANCH CIRCUIT INTENDED TO
PROVIDE POWER TO TASK ILLUMINATION,
SPECIAL POWER CIRCUITS, AND SELECTED
RECEPTACLES SERVING AREAS AND
FUNCTIONS RELATED TO PATIENT CARE. IT
MUST AUTOMATICALLY CONNECT TO AN
ALTERNATE POWER SOURCE SUCH AS A
GENERATOR WHEN THE NORMAL POWER
SOURCE IS INTERRUPTED.

10. [ DEVICE AND EQUIPMENT REQUIREMENTS ]
1. SWITCHES MUST BE SELECTED TO MATCH THE LOAD THEY
CONTROL.
2. A PANELBOARD LIKE ENCLOSURE CALLED LIGHTING CONTROL
PANEL IS USED IN LARGE LIGHTING INSTALLATIONS THAT
REQUIRE MANY SWITCHES.
3. RECEPTACLES MUST BE SELECTED TO MATCH THE APPLIANCE OR
EQUIPMENT THEY SERVE.
4. NORMALLY, SWITCHES ARE MOUNTED APPROXIMATELY 48
INCHES (1.2 METERS) ABOVE FINISHED FLOOR (AFF),
CONVENIENCE RECEPTACLES AT 16 INCHES(0.4 METERS) AFF
AND CONVENIENCE RECEPTACLES IN BATHROOMS AND
RESTROOMS AT 44 INCHES (1.1 METER) AFF, UNLESS OTHERWISE
SPECIFIED.

11. [ CONDUCTOR REQUIREMENTS ]
COPPER AND ALUMINUM ARE THE MOST COMMON
CONDUCTOR MATERIALS USED IN BUILDING ELECTRICAL
WIRING, ALTHOUGH OTHER MATERIALS CAN BE USED. AS A
GENERAL RULE, SOLID COPPER CONDUCTORS ARE USED IN SMALL
CONDUCTOR SIZES (UP TO ABOUT 8 AWG) BECAUSE SAFETY
ISSUES ASSOCIATED WITH ALUMINUM ARE AVOIDED AND
WEIGHT AND COST ARE NOT SIGNIFICANTLY AFFECTED.

12. [ CONDUCTOR
REQUIREMENTS ]

13. [ CABLE, RACEWAY, ENCLOSURES REQUIREMENTS ]
ALL BUILDING WIRING MUST BE ENCLOSED IN A CABLE, CONDUIT,
WIREWAY, OR RACEWAY. DURING INSTALLATION, CONDUCTORS ARE
SNAKED THROUGH CONDUIT OR TUBING, ARE LAID IN A WIREWAY, OR ARE
CONTAINED IN CABLES AND SECURED TO STRUCTURAL FRAMING. CARE
MUST BE EXERCISED IN PLACING CONDUCTORS, AS CONDUCTORS AND
INSULATION CAN BE EASILY DAMAGED.

14. [ CABLE, RACEWAY, ENCLOSURES REQUIREMENTS ]
FOR EXAMPLE, IF A CONDUCTOR IS PULLED THROUGH A TIGHT
CONDUIT, IT CAN STRETCH. DEFORMATION CAUSED BY STRETCHING
REDUCES THE CROSS-SECTIONAL AREA OF THE WIRE, THEREBY
REDUCING ITS AMPACITY. THIS CREATES AN UNSAFE CONDITION
BECAUSE THE CONDUCTOR CAN OVERHEAT.

15. [ CABLE, RACEWAY, ENCLOSURES
REQUIREMENTS ]
CONDUCTORS THAT ARE RUN THROUGH A RACEWAY MUST
HAVE SUFFICIENT OPEN-AIR SPACE TO PREVENT OVERHEATING. THE
NUMBER OF CURRENT-CARRYING CONDUCTORS THAT CAN RUN
THROUGH A RACEWAY IS LIMITED BY CODE.

16. [ CABLE, RACEWAY, ENCLOSURE REQUIREMENTS ]

17. [ CABLE, RACEWAY, ENCLOSURES REQUIREMENTS ]
ALL ELECTRICAL CONNECTIONS MUST BE MADE IN A PROTECTIVE
ENCLOSURE SUCH AS A PANELBOARD, JUNCTION, OR DEVICE BOX,
FIXTURE, OR APPLIANCE. EVERY SWITCH, OUTLET, AND CONNECTION MUST
BE CONTAINED IN AN ELECTRICAL BOX AND EVERY LIGHTING FIXTURE
MUST BE MOUNTED ON A BOX.

18. [ CABLE, RACEWAY, ENCLOSURES REQUIREMENTS ]
THERE ARE NO REQUIREMENTS THAT SPECIFY THAT A CERTAIN
TYPE OF ELECTRICAL BOX BE INSTALLED FOR A SPECIFIC PURPOSE. THE
TYPICAL TRADE PRACTICE IS TO INSTALL OCTAGONAL AND ROUND
BOXES FOR LIGHTING OUTLETS AND TO INSTALL RECTANGULAR AND
SQUARE BOXES FOR SWITCHES AND RECEPTACLE OUTLETS.

19. [ CABLE, RACEWAY, ENCLOSURE REQUIREMENTS ]

20. [ ELECTRICAL DESIGN PRINCIPLES ]
( Engineering Utilities 1 )
END