Date post: | 23-Dec-2015 |
Category: |
Documents |
Upload: | cameron-harmon |
View: | 216 times |
Download: | 0 times |
Residential Wiring
By: Ing. Hector M Lugo-Cordero, MS
03/25/2009
Agenda
• 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
– 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