How an Electrical System Works

  • 01 of 09

    Introduction

    An image of a Utility Company Transformer
    Utility Company Transformer. TimothyThiele

    We all use electricity in our homes every day, but how does it get there and how is it distributed throughout the home. In order for electricity to function properly, it must always complete a circuit.

    Electricity flows in from one of two 120 volt wires and back out through a grounded neutral wire. Any flaw in the wire to and from these points will interrupt the current’s path and cause a fault in one of your circuits.

    Knowing how the power flows into your home, how it’s connected and how it is...MORE distributed can help you isolate any problems that occur.

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  • 02 of 09

    Service Entrance

    Service Entrance
    Service Entrance. Timothy Thiele

    The utility company’s overhead service lines feed the transformer to step down the voltage to feed your home. It then travels to the weather head (service head) which is attached to a conduit connected to a meter box. This assembly is attached with anchor bolts and straps in order to support the weight of the pipe and wire.

    Two 120 volt wires and a grounded neutral wire feed the meter through the weather head. The utility company is responsible for power to the meter and the homeowner takes it...MORE from there.

    The service from the utility company to the meter is always live unless they come and turn it off. If there appears to be a problem on their side of the meter, don’t hesitate to call them to repair the problem. They have special equipment for just such repairs. Never attempt to work on their side of the meter, ever!

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  • 03 of 09

    Electric Meter

    Electric Meter
    Electric Meter. Timothy Thiele

    The electric meter is attached to the service entrance pipe and is usually attached to the side of your house. It may be attached to the utility company’s power pole also. It can be fed overhead or underground.

    The meter is a watt measuring device supplied by the utility company to track each month’s power consumption. There are meters with numbered dials like a watch on older models and new state-of-the-art digital meters that can be read right from the utility company’s office.

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  • 04 of 09

    Weatherproof Disconnect

    Weatherproof Disconnect
    Weatherproof Disconnect. Timothy Thiele

    In most cases, the utility company will require a weatherproof disconnect right after the meter connection. This is often referred to as a safety switch or service disconnect. This allows the homeowner to disconnect the power from the utility company from the outside of the house without having to get to the electrical panel.

    A great reason for this would be a house fire. The fire department can kill the power from outside the home without entering the home. This allows them to spray water on a...MORE fire without worrying about being electrocuted.

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  • 05 of 09

    Electrical Panel

    Electrical Panel
    Electrical Panel. Timothy Thiele

    The electrical panel, breaker box, fuse box or service panel (it is known by many names) is the next device in line. This panel’s job is to distribute power throughout your home and disconnect power from the incoming feed.

    The power comes into the main breaker and is usually 100 or 200 amps. Individual breakers then distribute individual circuits (called branch circuits) throughout your home.

    These breakers range in size from 15 to 100 amps. Lighting circuits would be 15 amps, outlet circuits...MORE would be 20 amps, and a sub panel circuit to a garage or tool shed would usually be 60 or 100 amps.

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  • 06 of 09

    Grounding Wire and Water Ground Connection

    An image of a ground rod connection.
    Ground Rod Connection. Timothy Thiele

    The service must be connected to a ground rod outside the house and also bonded around the water meter in the house. A jumper connected on both sides of the meter must be made to allow the meter to be removed without losing a ground connection.

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  • 07 of 09

    Approved Electrical Boxes

    Electrical Box
    Electrical Box. Timothy Thiele

    The branch circuits are run into electrical boxes that are mounted inside of the walls of every room of your house. The National Electric Code requires that wires be spliced in boxes.

    The reason is to make every connection accessible. For instance, if you just splice the wires together and tape them within the wall cavities with no box and cover it with drywall, how will you get back to it to work on the splice if there’s a problem? You can open a box at any time.

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  • 08 of 09

    Switches

    Switches
    Switches. Tim Thiele

    Switches come in many different styles. There are single pole, three-way, four-way, dimmer, and motion-sensing switches. Their purpose is to turn on and off a circuit from different places in your home. Switches are used to control lighting, ceiling fans, receptacles, and appliances. Switches have different amperage ratings depending on the load requirements.

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  • 09 of 09

    Receptacles

    Receptacles
    Receptacles. Tim Thiele

    Receptacles, commonly referred as outlets, are used to provide individual plug-in points for power distribution. The housing market most frequently uses 125-volt, 15 and 20-amp receptacles for general household equipment. For appliances like 250-volt window air-conditioning units, a 250-volt 30-amp outlet is required.

    Hopefully, having learned the basic parts of the electrical system will be useful to you in the future. Knowing how everything flows from start to finish helps in tracking down...MORE electrical problems that might arise.