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Power
poles carry high-volt, low-amp electricity. This lets power company transmit electricity long-distance without heat loss caused by high amperage. Before entering house, electricity is converted to lower volts and higher amps at transformer. Different transformers are used for different voltages. Residential transformers receive power from 1 high voltage line. The transformer reduces voltage to 120Volts and splits the voltage into two 'out-of-phase' 120Volt Hot wires that enter home. Homes with underground utilities have meter and meter box, but wires arrive in conduit pipe from underground. Transformers are inside ground-level boxes at edge of property. Notice 3 wires enter home <> 2 hot wires and 1 neutral wire <> the neutral is a ground that connects to ground wire at pole Read about transformers Read more Read details about 3-phase |
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Three
wires drop down from weather head and enter meter box. There are 2 hot wires and 1 neutral wire. The 2 hot wires come from the transformer. The neutral is connected to ground wire at telephone pole. The meter 'stabs' into meter box using 4 prongs, similar to extension cord plugging into a wall socket. The meter completes the circuit and lets electricity flow to house. The 3 wires exit meter box and go to Main Breaker Box |
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Image
shows meter and meter box: Pulling a meter requires a stout pull downward and then upward <> usually you pull downward on the top of meter and then push up, going up & down to loosen and remove meter > removing meter will turn off electricity to whole house including breaker box <> however meter box will still contain live electricity <> stand on dry boards when pulling meter <> turn off all circuit breakers in main breaker box before pulling or re-installing meter so there is no arc of electricity just as meter prongs makes contact with lugs |
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Ordinary household wiring is called 'single-phase' or 'split phase.' 120 volt is generally called single-phase and 240 volt is split-phase. The available voltage is determined by how the electric company sets up the transformer. 2 Hot wires and 1 neutral wire arrive from meter box. Blue color added to 1 hot wire for illustration <> in real breaker box, the 2 hot wires are black The 2 hot wires connect to the Main Breaker <> a lug is tightened very tight to hold wire in place. Neutral is connect to neutral busbar. Each hot wire connects to different busbar through the main breaker > here the busbars are named A and B > the 'blue' hot wire provides power to blue busbar <> remember, blue color added for illustration only Hot busbars are 120 Volts each > they never touch each other > they are suspended away from the main box by insulators 240 Volt potential exists between busbar A and busbar B |
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Image shows 120Volt line and 240volt line. Both circuits have ground wire. Each 120 and 240 require two wires to complete circuit. 120V requires 1 hot and 1 neutral 240V requires 2 hots Ground wires are for safety. Some 240Volt lines have additional neutral wire. However, neutral not necessary to complete 240Volt circuit. Some 240Volt lines have white and black instead of red and black Mose service boxes today have separate Neutral and Ground busbars, but these busbars are bonded together electrically, and are the same. Illustration on left shows older style box with single busbar for both Neutrals and Grounds. Wire sizes Basic 120 volt and 240 volt water heater circuits How to wire 240 volt outlets How to wire 3-phase outlets and timers How to convert 240Volt water heater to 120volts |
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How to install electric meter on water heater |
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How
to replace circuit breaker Breakers are held in place at both ends <> one end locks into a cleat -or- snaps onto a bar <> other end of breaker rotates to busbar and then 'stabs' onto the busbar Push firmly to make sure breaker is stabbed all the way down When replacing a breaker, check busbar for damage or burning from previous breaker <> busbars are frequently damaged by aging breakers that arc and burn <> arcing will damage busbar so new breaker will no longer work in the same slot. Read steps 32-37: When lights flicker, check breaker immediately before sparking causes damage in breaker box. Check breaker and listen for fizzing or crackling sound. Check if the breaker screw is tight against wire. Flickering lights are usually a loose wire at a plug, but it pays to check breaker first to avoid busbar damage. Always put cover back on breaker box to prevent sparks from leaving breaker panel. Read how to replace circuit breaker |
