How does electricity reach your house?
Power is generated in a power plant managed by your electrical utility company. Some utility companies in New Jersey are Atlantic City Electric, Jersey Central Power and Light, Orange Rockland Electric, and PSE&G. Electricity is sent to your home via a series of cables, switches, and transformers. It is usually transmitted at high voltage levels, in order to minimize Joule heating. These voltage levels are usually around 120V. This means that each coulomb of charge that reaches your house brings with it 120 joules of energy.
The power reaches your house after passing through your meter, where your monthly electricity consumption is recorded. The power then passes through the main panel, or fusebox, of your house. From here it is directed to a number of different branches, flowing throughout your house and supplying electricity to various appliances, before returning back to the fusebox. The fusebox also contains mechanisms to turn power off if it exceeds a certain limit - more on those later.
What is a circuit?
Before understanding how power is distributed throughout your house, you first need to understand what a circuit is. A circuit is a path through which electricity flows. It is easy to analyze a circuit if there is only one path that the electricity can take, as is seen in a series circuit. However, the wiring in your house is done in parallel, with branches splitting into branches and diverting electricity to where it is needed.
How does electricity reach a device?
So what happens when you turn on an appliance? The fusebox sends current to the appliance through the appropriate branch. (This is analogous to opening a faucet and having water flow out.) The electrical energy is then used to run your appliance — enabling you to turn on a light, spin a fan, charge a phone, or toast a slice of bread. After passing through your appliance, the used-up charge travels back to the fusebox, from which it is grounded, or sent into the earth.
Power comes to appliances through the hot wire, the shorter hole in an outlet, labeled above in red. It is used, and then sent back to the fusebox through the neutral wire, the larger hole, labeled in purple. The ground wire, in blue, is not really part of the circuit. However, in the event of too much current coming through the outlet, the ground wire is useful for preventing a shock by providing a quick discharge path.
Why are homes wired in parallel?
The two outlets in a panel (as shown above) receive power from the same branch leading off of the fusebox. They are wired in parallel so that appliances plugged into them receive the same voltage, but can operate at their own current levels. This is the logic behind parallel wiring throughout a house. The same voltage is maintained everywhere, but appliances only draw as much current as they need.
In addition, should one appliance blow, the massive circuit running throughout your house is not shut down. Rather, only the branch containing that one device is inactive.
In addition, should one appliance blow, the massive circuit running throughout your house is not shut down. Rather, only the branch containing that one device is inactive.
This raises a question: if current varies from branch to branch, what prevents one appliance from getting too much current?
In fact, there are quite a few mechanisms in place to prevent that from happening, because it might result in a short circuit, an electric shock, or a fire. Read on to learn more about these devices.
In fact, there are quite a few mechanisms in place to prevent that from happening, because it might result in a short circuit, an electric shock, or a fire. Read on to learn more about these devices.