1. Residential Wiring By: Ing. Hector M Lugo-Cordero, MS 03/25/2009

2. Agenda Residential circuits Improving power consumption Sockets Switches Cables Protection devices Service panel Distribution panels Electrical symbols

3. 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(a v – a i ) –cos(a v – a i ) is the power factor If a motor is added (e.g. celing fan, refrigerator) –Demand Q = VIsin(a v – a i ), as well as P –sin(a v – a i ) is the reactive factor

4. 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

5. 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

6. Switches Switches allow the user to control a load (on/off) Examples –Single –Double –3 way –4 way –Combined –Pilot light

7. 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

8. 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

9. Size of Cables (cont.)

10. 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

11. 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

12. Distribution Panels Load balancing: the act of distributing equally all 120V loads

13. Electrical Symbols