Basic House Wiring

Electrical Measurement Terms

• Amp - measures the rate of flow of electrical current

• Volt - measure of pressure or force pushing electricity

• Ohm - measure of electrical resistance

• Watt - basic measure of electricity (amps x volts = watts)

Other Basic Terms• Ground - connector that runs between a

device or circuit to safely conduct current to earth

• Conductor - device intended to carry electrical current

• Insulator - material that is a poor conductor of electricity; used to prevent electrical flow

• Short circuit - accidental connection between two conductors

• Overload - to run equipment in excess of its normal full load

Where does electricity come from?• 1) Generation

– Nuclear fission - split atoms– Hydro power - moving water– Burning fossil fuels - power plants

• 2) Step-up transformer – Voltage stepped up in transformer to between

69 and 345 thousand volts (sometimes even higher)

• 3) Transmission lines– Electricity travels through wires over long

distances

Where does electricity come from? (continued)

• 4) Step-down transformer– Voltage stepped down in transformer at substation to

between 2000 and 13000 volts• 5) Distribution Lines

– Electricity travels around community (sometimes above ground and sometimes below ground

• 6) Distribution transformer– Steps down voltage to between 120 and 240 volts for

use in business or home• 7) Customer line

– Electricity enters homes or business

Circuit

• Path for electricity– Closed - electricity is allowed to flow– Open - electricity is stopped

• Many circuits within a home

Fuse/Circuit Breaker Boxes

• Each branch circuit is protected by fuses or circuit breakers

• If too much current is used, fuses or breakers will open the circuit – Fuse - if blown needs to be replaced– Circuit breaker - “trips” to open circuit; may be

reset

Voltage

• Two wires carry 120 volts each– 120 used for lights and small appliances

(outlets)

• Two wires combined for 240 volts – 240 volts used for large appliances (oven,

dryer, hot water heaters, air conditioners)

Basic Electrical Tool Kit• Screwdriver• Long-nose pliers (similar to needle nose but has

curved ends)• Lineman’s Pliers• Side Cutters - Diagonal-cutting pliers• Tin Snips• Wire Stripper/Cutter (Multipurpose tool)• Cable Ripper• Fuse Puller• Fish Tape• Conduit Bender

Testers

• Receptacle analyzer

• Voltage tester

• Continuity tester

• Multimeter (has specific settings to test all - voltage, amperage, and resistance)

Basic Electrical Relationship

• Ohm’s Law– I = amperage (the flow of electrons)

– R = resistance (resistance to the flow)

– E (or V) = voltage (force behind electrons)

– E = I x R

E (or V)

I R

Basic Skills for Replacing an Extension Cord End

• Use a wire ripper to slice cable sheathing

• Remove cable sheathing

• Use a wire stripper to remove insulation around each wire

• Make necessary connections– Hook wire clockwise over screws– Twist wire clockwise for wire nuts

Wire Identification

• Black wire - “hot”...electricity is brought to devices through this wire

• White wire - “neutral”...electricity goes back through this wire

• Bare Copper or Green wire - “ground”...safety for all stray electricity

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Long Nose Pliers

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Lineman’s Pliers

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Side Cutters

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Tin Snips

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Wire Stripper/Cutter

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Cable Ripper

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Fuse Puller

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Fish Tape

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Conduit Bender

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Receptacle Analyzer

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Voltage Tester

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Continuity Tester

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Multimeter