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Why is electrical bonding necessary?

In a house wiring system, it would seem shorting hot to earth ground (not bonded) should cause the same amount of current to flow as if hot is shorted back to the service neutral via bonding. However, the NEC code is clear that the ground bus must be bonded to the incoming neutral, and I have seen experiments on the web showing this is true. Why isn't grounding without bonding sufficient?

Update:

I'm not asking why grounding is needed. That makes lots of sense. I don't know why bonding (connecting the grounding bus to the incoming neutral of the power company) is needed. Basically, why must the grounding wire have a path back to the power company instead of just to earth.

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  • Pat
    Lv 6
    10 years ago
    Favorite Answer

    The union guy has the best answer here. He knows his theory. Bonding as you call it is the permanent joining of a metallic from any electrical conductive path that will ensure electrical continuity and large enough to safely carry the current yo ground or earth.

    In your service in your home (if in the US) you have 2 hot wires that carry 120 volts each split between them at the transformer is a neutral yes it is grounded and this is a grounded conductor. When you plug in a 120 volt device the current flows through from the transformer through your breaker through the device and back through the neutral bar back to the transformer to complete the circuit. That is why the neutral is called a grounded conductor it does carry current. When you plug up a 240 volt appliance it merely uses the 2 hot wires and they go back and forth with out a neutral and complete the path.

    The ground is there in case of a short in your 120 volt side to anything that it can come in contact with and if it is grounded to earth it will short out and you do not get a shock or worse.

    Even though the neutral is grounded at the transformer it has to be grounded in your panel as well to ensure the shortest path to ground. If your home was not grounded and you took a hit from lightning it would go through your home before it made it back to the transformer. The bulls eye is the ground bar in your home. If you can you always have as many grounds as you can water pipes Ground rods and other ways to ensure that the path of any conductivity is going back to earth which has a zero potential to save lives and equipment.

    Source(s): Electrical Contractor |><|
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  • 5 years ago

    This Site Might Help You.

    RE:

    Why is electrical bonding necessary?

    In a house wiring system, it would seem shorting hot to earth ground (not bonded) should cause the same amount of current to flow as if hot is shorted back to the service neutral via bonding. However, the NEC code is clear that the ground bus must be bonded to the incoming neutral, and I have seen...

    Source(s): electrical bonding necessary: https://shortly.im/23wuL
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  • 10 years ago

    the neutral doesn't go back to the power company if you look there is only 1 wire in the supply, neutral is a directed earth, earth is an "emergency" route back to earth, AC current only has a live (plus and minus potential difference) and a neutral/earth

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  • 10 years ago

    the neutral bar must be grounded at the panel to make it the same voltage as ground, which is to say, none. this prevents a phenomenon known as a "floating ground" where, although you have 120V from hot to neutral, it's possible to have 600 volts (or more!) from hot to ground. not safe in the least.

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  • 10 years ago

    IF YOU LOSE THE NEUTRAL THAT IS SUPPLIED BUY THE POWER CO.!

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