HOUSE WIRING Final Review

Electricity Electricity = flow of electrons Conductor= electricity passes thru easily - Metal, water, person Insulator = restricts electrical flow Rubber, plastic, wood, paper

Circuits Circuit = path for electricity to flow Types Series – one path, if one part doesn’t work, nothing works. Parallel – more than one path (alternate routes), if one path doesn’t work the others can still.

Loads/Device Load - anything that make electricity useful for us. Light, outlet, anything plugging into outlet, motors Device – anything that controls the flow of electricity Switch, breaker, fuse

Measuring Electricity Voltage – Potential difference, the force to start the flow of electricity. Measured in Volts Amperage - The flow of electricity in the circuit. Measured in amps. Resistance - The opposition to the flow of electricity. Measured in ohms.

Current Current is the flow of electricity. Types of current DC (Direct Current) A current that flows in one direction only AC (Alternating Current) Changes direction 60 times per second

NEC National Electrical Code – Sets and enforces a set of rules, regulations, and criteria for the installation of the electrical equipment.

OSHA Occupational and Safety Health Act – Creates and enforces health and safety standards in the workplace. This organization protects persons in all occupations in the U.S.

UL Underwriters Lab = test electrical equipment abd determine what the uses can be. You may not use equipment for something it has not been rated for

OHM’S LAW Current in a circuit is directly proportional to the voltage and inversely proportional to the resistance of a circuit. Voltage (E)= Current X Resistance Volts = Amps X Ohms Current (I)= Voltage / Resistance Amps = Volts / Ohms Resistance (R)= Voltage / Current Ohms = Volts / Amps E I R volts ampsohms

SERIES CIRCUIT RULES 1) The current is the same throughout. 2) Resistance is the sum of the individual resistances. 3) Voltage at the source is equal to the sum of the voltages at each resistor. 4) A break anywhere in the circuit stops the electrical flow in the entire circuit. 5) Ohm’s law applies to any part of the entire series circuit.

PARALLEL CIRCUIT RULES 1) Voltage is the same throughout the parallel circuit. 2) The total current is equal to the sum of the current from each branch. 3) The total resistance is the reciprocal of the sum of the reciprocals of the separate resistances in parallel. 4) Ohm’s law applies equally to the total circuit or any branch. 5) A break or opening in any branch does not stop the flow of electricity to the remaining branches.

POWER Power is the rate of doing work, measured in watts or volt- amperes. Power = Voltage X Amperage Watts = Volts X Amps Voltage = Power / Amperage Volts = Watts / Amps Amperage = Power / Voltage Amps = Watts / Volts Kwh = 1000 watts per hour P E I watts volts amp s

AWG American Wire Gauge – The sizing of the electrical wire. AWG 10, 12, 14 is used for residential wiring. AWG 18, 20, 22 is used for our small board jobs. The larger the number the smaller the wire.

THE IMPORTANCE OF WIRE SIZE Ampacity – The safe current carrying capacity of the wire. Voltage Drop – Loss of electrical pressure due to the length or thickness of the wire.

INSULATION COLOR HOT – Dark colors (Black, Red, Blue) Brings electricity from the panel to the circuit. Is always hot. NEUTRAL – (White, Gray) Returns power to ground from the loads on the circuit. SWITCH LEG – Colors other than HOT or NEUTRAL (Yellow) Supplies power from the switch to its load. TRAVELER – Same as switch leg. Pathway from one switch to another switch. GROUNDING CONDUCTORS – (Bare or Green) Bonds the boxes and devices to ground.

CIRCUIT PROTECTION Circuits are prone to over-currents due to overloads or short circuits. Fuses and Breakers – Devices that stop the flow of electricity within short circuits or overflows. Overloads – Too many devices on one circuit. Short circuits – When two conductors unintentionally touch each other or create a path.

SAFETY Safety – Ensure that circuit is disconnected and dead before beginning work on it. Use tools correctly and for their intended purpose. Remove all jewelry, watches, and rings to avoid metal-to- metal contact with energized circuits. Keep the work area dry and free of debris. Ensure all electrical equipment is properly grounded. Ladders should only be made of wood or composite material.

GROUNDING The most important element in wiring. Safety is proper grounding. Grounding is the connection of all parts of a wiring circuit to ground. This provides protection to persons, the electrical system itself, and the building. Electrical circuits are grounded by driving a ground rod at least eight feet deep into the earth or connecting to a metallic cold water pipe at least 10 feet in length or a buried ground plate.

SERVICE PANEL Where electricity enters the residence. Contains the hot bar, neutral bar, grounding bar (bonded), and circuit breakers. Is grounded through grounding rod 8 feet deep or to the cold water piping or both.

NEC Article 90.4 allows Local municipalities are given the power of attorney to interpret Code Article – requires 6” excess wire for every opening

Device Wiring NEC Articles 110 and 300 cover device wiring Connections – must be clean and secure contact to devices All connections must be made within boxes or enclosures Hooks – hooks are clockwise and should be clean and secure under the screw Splices – Are to be made clockwise and covered with caps of equal or greater insulation

Switches Single pole switches = 2 screw terminals, on/off, 1 location 3 way switches = 3 screw terminals, a common screw terminal, 2 locations 4 way switches = 4 screw terminals, between two 3 ways, 3 locations

Location Switches = latch side of door at about 48 inches Outlets = within 6 feet along any wall at 12 inches off ground GFCI outlets = wherever they can get wet Protected outlets further from the service panel than GFCI

Breaker Box