Download Residential Wiring

Residential Wiring
By: Ing. Hector M Lugo-Cordero, MS
03/25/2009
Agenda
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Residential circuits
Improving power consumption
Sockets
Switches
Cables
Protection devices
Service panel
Distribution panels
Electrical symbols
Residential Circuits
• Residential loads are connected in parallel,
since the voltage remains the same through the
loads and if a circuit fails it does not affect the
others
• Purelly resistor load (e.g. lights, toaster)
– Demand P = VIcos(av – ai)
– cos(av – ai) is the power factor
• If a motor is added (e.g. celing fan, refrigerator)
– Demand Q = VIsin(av – ai), as well as P
– sin(av – ai) is the reactive factor
Improving Power Consumption
• Add a capacitor/capacitor block in parallel
to the load
• Make sure is the right one
• Don’t add it to purely resistor circuits
Sockets
• A power socket is used for connecting
appliances.
• Big hole specifies the neutral end (to source)
• Small specifies the hot end (from source)
• Examples
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125V @ 15A
125V @ 20A
230V @ 30A
Ground Fault
Arc Fault
Switches
• Switches allow the user to control a load
(on/off)
• Examples
– Single
– Double
– 3 way
– 4 way
– Combined
– Pilot light
Cables
• Black – hot, connection from the AC
source to switch typically
• Red – return, connection from switch to
load
• White – neutral, connection from load back
to the AC source, it closes the circuit
• Green – ground, protects people from
electrically charged metal parts
Size of Cables
• 14: minimum approved width in United
States for residential wiring. In PR we can
use it for lamps wiring
• 12: minimum approved width in Puerto
Rico for residential wiring
• 2: cable used from service panel to
distribution panel, passes up to 100A of
current
Size of Cables (cont.)
Protection Devices
• Breakers: work like a fuse, opens
current path when threshold is
exceeded. This protects the
circuits from high currents, no
protection to people
• Ground connection: connection to
ground so that users are
protected from alternate current
paths, like breakers they open the
current path but when a current
change is found
Service Panel
• Nude cable comes
from transformer
• It then changes to a
white cable and
connects to the box
• From here a
connection to
breaker and ground
is done
Distribution Panels
• Load balancing: the act of distributing
equally all 120V loads
Electrical Symbols