Download 275DAY4CHAPTER3OUTLETS Lecture Notes Page

DAY 4 CHAPTER 3 CONDUCTOR SIZES,TYPES, ETC.
Continuous Load. A load where the maximum current is expected to continue for 3 hours or more.
Continuous loads shall not exceed 80% of the rating of the Branch circuit
CIRCUIT BREAKERS ARE THE FINAL OVERCURRENT PROTECTION DEVICE
Branch Circuit. The circuit conductors between the finalovercurrent device protecting the circuit and the outlet(s).
BRANCH CIRCUIT HAS 3 PARTS 1. CIRCUIT BREAKER 2. CONDUCTOR 3. DEVICES
THERE ARE 4 TYPES OF BRANCH CIRCUITS.
1. SMALL APPLIANCE. 2. INDIVIDUAL 3. GENERAL PURPOSE 4. MULI-WIRE.
Branch Circuit, Individual. A branch circuit that supplies only one utilization equipment.
Branch Circuit, Appliance. A branch circuit that supplies energy to one or more outlets to
which appliances are to be connected
Branch Circuit, General-Purpose. A branch circuit that supplies two or more receptacles or outlets for lighting
and appliances.
Branch Circuit, Multiwire. A branch circuit that consists of two or more ungrounded conductors that have a
voltage between them, and a grounded conductor that has equal voltage between it and each ungrounded
conductor of the circuit and that is connected to the neutral or grounded conductor of the system.
TYPE NM CABLE MUST HAVE A BENDING RADIUS AT LEAST 5 TIMES THE DIAMETER OF THE CABLE.334.24
COLOR CODE FOR NM-B CABLE
CONDUCTOR SIZE
14 AWG
12 AWG
10 AWG
8 AWG
COLOR
WHITE
YELLOW
ORANGE
BLACK
6-32: FIXING RECEPTELES TO DEVICE
BOXES AND FACE PLATES ALSO FOR
PLASTIC BOXES.
8-32: ATTACHING MUD RINGS TO
BOXES
10-32: CEILING FAN
BOXES,GROUND SCREWS
MAXIMUM OVERCURRENT FOR
14AGW = 15AMPS
12AGW = 20AMPS
10AWG = 30AMPS
INDIVIDUAL BRANCH CIRCUIT HAS 1 HOT,1 NETURAL
MULTI-WIRE CIRCUITS HAVE 2 HOTS, 1 NETURAL
COLOR CODE
WHITE IS RESERVED FOR NEUTRAL(GROUNDED CONDUCTOR)
GREEN IS RESERVED FOR (GROUNDING CONDUCTOR), CAN ALSO BE BARE.
BLACK, RED, ETC ARE HOT.(UNGROUNDED CONDUCTOR)
3 METALS ARE ALLOWED FOR CONDUCTORS
1.COPPER
2.ALUMINUM
3 COPPER CLAD ALUMINUM
FOR A 15A CIRCUIT.
FOR A 20A CIRCUIT.
Branch Circuit. The circuit conductors between the final
overcurrent device protecting the circuit and the outlet(s).
BRANCH CIRCUIT HAS 3 PARTS 1. CIRCUIT BREAKER
2. CONDUCTOR
3. DEVICES
Feeder. All circuit conductors between the service equipment,
the source of a separately derived system, or other
power supply source and the final branch-circuit overcurrent
device.
Continuous Load. A load where the maximum current is expected to continue
for 3 hours or more. Continuous loads shall not exceed 80% of the rating of the
Branch circuit
Some loads in homes are continuous, such as electric water heaters, central electric
heating, A/C. For these loads branch circuit rating, conductors, and the overcurrent
devices can’t be less then125% of the load.
Example: A/C with a name plate rating of 40amps, requires conductors and a
circuit breaker with a rating of
40amps 1.25  50amps
this is the same as
80% of 50amps  40amps
CIRCUIT BREAKERS ARE THE FINAL OVERCURRENT PROTECTION DEVICE
THERE ARE 4 TYPES OF BRANCH CIRCUITS.
1. SMALL APPLIANCE.
2. INDIVIDUAL
3. GENERAL PURPOSE
4. MULI-WIRE.
Branch Circuit, Appliance. A branch circuit that supplies energy
to one or more outlets to which appliances are to be connected
and that has no permanently connected luminaires that are not a
part of an appliance.
Branch Circuit, Individual. A branch circuit that supplies
only one utilization equipment.
Branch Circuit, General-Purpose. A branch circuit that
supplies two or more receptacles or outlets for lighting and
appliances.
SUPPLIES ONLY ONE PIECE OF EQUIPMENT
Branch Circuit, Multiwire. A branch circuit that consists
of two or more ungrounded conductors that have a voltage
between them, and a grounded conductor that has equal
voltage between it and each ungrounded conductor of the
circuit and that is connected to the neutral or grounded
conductor of the system.
MAXIMUM OVERCURRENT FOR
14AGW = 15AMPS
12AGW = 20AMPS
10AWG = 30AMPS
INDIVIDUAL BRANCH CIRCUIT HAS 1 HOT,1 NETURAL
MULTI-WIRE CIRCUITS HAVE 2 HOTS, 1 NETURAL
COLOR CODE
WHITE IS RESERVED FOR NEUTRAL(GROUNDED CONDUCTOR)
GREEN IS RESERVED FOR (GROUNDING CONDUCTOR), CAN ALSO BE BARE.
BLACK, RED, ETC ARE HOT.(UNGROUNDED CONDUCTOR)
3 METALS ARE ALLOWED FOR CONDUCTORS
1.COPPER
2.ALUMINUM
3 COPPER CLAD ALUMINUM
200.7grounded circuit conductor, (A)
(1) A conductor with continuous white or gray covering
(2) A conductor with three continuous white stripes on
other than green insulation
(3) A marking of white or gray color at the termination
250.119 Identification of Equipment
Grounding Conductors. (B)
shall be permitted to be bare, covered, or
insulated. Individually covered or insulated
equipment grounding conductors shall
have a continuous outer finish that is either
green or green with one or more
yellow stripes
Ungrounded conductor (hot) can be any color
Other than white, gray, green, or green with
Yellow strips. (C)
AMPACITY: CURRENT CARRYING CAPACITY OF A CONDUCTOR.
THE ALLOWED AMPACITY OF CONDUCTORS IN RESIDENCES IS FOUND
IN TABLE 310.16. THESE AMPACITIES ARE SUBJECT TO CORRECTION
FACTORS FOR HIGH AMBIENT TEMPERATURES. THESE ARE FOUND AT
THE BOTTOM OF T 310.16. p70-148
T310.16 IS FOR THREE OR LESS CONDUCTORS IN A RACEWAY OR CABLE.
EXAMPLE: A 12AWG THHN COPPER CONDUCTOR AT 90°C
IS RATED AT 30AMPS. IF THE AMBIENT TEMP. IS 56°C THE
CORRECTION FACTOR IS 0.71. USING THIS GIVES;
30AMPSX0.71=21.3AMPS, THIS IS THE DERATED USABLE
AMPERAGE FOR THIS 12AWG CONDUCTOR.
IF THERE ARE MORE THEN 3 CONDUCTORS PRESENT A ADDITIONAL
CORRECTION FACTOR MUST BE APPILED AND IS FOUND IN TABLE
310.15(B)(2)(a) p70-146
(2)
GIVEN THE SAME WIRE GAUGE SIZE, THE HIGHER ITS INSULATOR
TEMPERATURE RATING IS, THE GREATER ITS AMPACITY WILL BE.
EXAMPLE: WHAT IS THE NUMBER OF RECEPTACLES
ALLOWED FOR 15A AND 20A BRANCH CIRCUITS
HOW MUCH POWER CAN BE USED BY A 15A CIRCUIT?
USING THE POWER EQUATION;
P  IV
P  15 A 120V
P  1800W
APPLYING THE 80% AMPACITY CORRECTION FACTOR GIVES;
1800W .80  1440W
WE ARE ALLOWED 180VA PER RECEPTACLE FROM 220.14(I) p70-59
USING DAVID’S RULE OF THUMB TO FIND # OF RECEPTACLES PER BRANCH CIRCUIT;
W
NUMBERRECEPTACLES  1440
180VA  8RECEPTACLES
FOR A 15A CIRCUIT.
HOW MUCH POWER CAN BE USED BY A 20A CIRCUIT?
USING THE POWER EQUATION;
P  IV
P  20 A 120V
P  2400W
USING 80% AMPACITY CORRECTION FACTOR GIVES;
2400W .80  1920W
GIVEN THAT 180VA PER RECEPTACLE FROM 220.14
USING DAVID’S RULE OF THUMB TO FIND # OF RECEPTACLES PER BRANCH CIRCUIT;
W
NUMBERRECEPTACLES  1920
180VA  10 RECEPTACLES
FOR A 20A CIRCUIT.
MAX. DISTANCE AROUND WALL CORNERS=12FT.
Fixed panels are counted as wall space
Sliding panels are not wall space
One family
Duplex
FISH TAPE(WIRE PULLERS) FOR PULLING WIRES THRU
CONDUIT: COME IN LENGTHS FROM 25 TO100 FEET
VARIOUS LOOPS AVAILABLE AS FISH TAPE ENDS
WIRE LOOP AT END OF FISH TAPE
A NITROGEN POWERED GUN FOR PULLING
GUIDE ROPES THRU CONDUIT UP TO 100’
How to Fish Wires Through a Conduit or Pipe
http://www.wikihow.com/Fish-Wires-Through-a-Conduit-or-Pipe