In simple AC power systems, one of the two conductors is typically called the hot, while the other conductor is typically called the neutral. What distinguishes the “hot” conductor from the “neutral” conductor in such a system? In other words, what exactly determines whether a conductor will be called either “hot” or “neutral”?
The presence of a “ground” wire increases the degree of electrical safety for anyone using an electrical appliance. It entails having a third “prong” on the power plug, connecting with a third hole on the power receptacle, which connects to a separate wire running all the way back to the power system’s grounding point:
But why not eliminate all that extra wiring, and simply connect the third hole on the power receptacle to the “neutral” wire?
Why would this idea be unwise?
In the United States of America, the National Electrical Code (NEC) specifies certain color codes to be used for designation of grounded, grounding, and ungrounded wires in AC power systems. First, relate the terms “hot,” “neutral,” and “ground” to the terms “grounded,” “grounding,” and “ungrounded”. Then, describe the acceptable color codes for each conductor. Also, note the article and section of the National Electrical Code under which these specifications are found.
Special safety devices called Ground Fault Current Interrupters, or GFCI’s, reduce the risk of shock hazard in electrical systems even where there is no ground conductor. Explain the operating principle of a GFCI. How are they able to sense a “ground fault” condition, so as to automatically turn off power to a receptacle?
I once watched a television advertisement for an electric drill, in which one of the people selling this product claimed it was “double-insulated,” to which the other person replied, “So it doesn’t get hot in your hand, right?”
What do you think of this comment? Is this what “double-insulated” means?
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