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Wire Electrical Disconnects

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Electrical Diconnect

Electrical Diconnect

Timothy Thiele
Electrical disconnects are generally mounted below the electric meter on the side of your home or on the utility company's power pole. Their purpose is to disconnect power to the home from the outside of the home. A great example would be in the event of a fire within the home. Neither you or the fire department wants to go into a burning building to turn off the power. The electrical disconnect can be shut off outside where the fire isn't and then the fire department can put out the blaze without fear of electrocution.
Difficulty: Average
Time Required: 15 - 30 Minutes

Here's How:

  1. Where Does The Feed Come From

    The electrical wiring to feed the disconnect is fed from the load side of the electric meter. There are two hot wires that both carry 120 volts and are different phases. These phases are normally called "A" and "B" phases. The total voltage when measured between them is around 240 volts. These wires connect to the disconnect breaker installed within the disconnect box. In this example, the breaker is a 100-amp Square D two-pole breaker.

  2. Feeding the Line Side of the Breaker

    The wires connect to the top two lugs of the breaker called the "line" side of the breaker. The neutral wire connects to the silver-colored lug along the side of the breaker. Mark this wire with white phasing tape to signify that it is the neutral wire.

  3. Feeding the Load Side of the Breaker

    The bottom of the breaker is for the "load" side wiring. The wires that connect here feed the electric panel in your home. Connect the two "hot" wires to the bottom of the breaker. The neutral wire connects to the silver-colored lug along the side of the breaker. Mark this wire with white phasing tape to signify that it is the neutral wire.

  4. What Do the Electrical Disconnect Wires Feed?

    The electrical disconnect feeds the breaker panel in your home. The feeder wires connect to the main breaker in the panel and the neutral wire connects to the neutral buss. Do you want to learn more about How an Electrical System Works?

  5. Things You'll Need

    Linesman Pliers
    To cut the wire.

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    Utility Knife

    To cut off the insulation from the wire.

    Straight Screwdriver

    To tighten the terminal lugs.

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    White Phasing Tape

    To mark the neutral wire.

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    Voltage Tester

    To check if the power is off, for safety.

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Tips:

  1. Safety First!
    Before performing any electrical installation, make sure that the power is turned off. Test the connections to be safe!
  2. Bend the wires in the general shape they need to be in to line up with the terminal lugs they will secure to.
  3. Only strip enough insulation from the wire to make the connection to the lugs. Too much bare wire is a safety hazard.
  4. Mark the neutral wire before cutting the excess from it.
  5. Try not to nick the bare copper wire while cutting off the insulation.
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