Circuit Breakers Very Useful For Your Home Electronical

How Circuit Breakers Work

Circuit Breaker: At Work in Your Home

The power distribution grid delivers electricity from a power plant to your house. Inside your house, the electric charge moves in a large circuit, which is composed of many smaller circuits. One end of the circuit, the hot wire, leads to the power plant. The other end, called the neutral wire, leads to ground. Because the hot wire connects to a high energy source, and the neutral wire connects to an electrically neutral source (the earth), there is a voltage across the circuit — charge moves whenever the circuit is closed. The current is said to be alternating current, because it rapidly changes direction. (See How Power Distribution Grids Work for more information.)

The power distribution grid delivers electricity at a consistent voltage (120 and 240 volts in the United States), but resistance (and therefore current) varies in a house. All of the different light bulbs and electrical appliances offer a certain amount of resistance, also described as the load. This resistance is what makes the appliance work. A light bulb, for example, has a filament inside that is very resistant to flowing charge. The charge has to work hard to move along, which heats up the filament, causing it to glow.

In building wiring, the hot wire and the neutral wire never touch directly. The charge running through the circuit always passes through an appliance, which acts as a resistor. In this way, the electrical resistance in appliances limits how much charge can flow through a circuit (with a constant voltage and a constant resistance, the current must also be constant). Appliances are designed to keep current at a relatively low level for safety purposes. Too much charge flowing through a circuit at a particular time would heat the appliance’s wires and the building’s wiring to unsafe levels, possibly causing a fire.

This keeps the electrical system running smoothly most of the time. But occasionally, something will connect the hot wire directly to the neutral wire or something else leading to ground. For example, a fan motor might overheat and melt, fusing the hot and neutral wires together. Or someone might drive a nail into the wall, accidentally puncturing one of the power lines. When the hot wire is connected directly to ground, there is minimal resistance in the circuit, so the voltage pushes a huge amount of charge through the wire. If this continues, the wires can overheat and start a fire.

The circuit breaker’s job is to cut off the circuit whenever the current jumps above a safe level. In the following sections, we’ll find out how it does this.



Maintenance and Testing

 Circuit Breaker Maintenance and RepairWhen selecting a circuit breaker the user must decide to either buy a unit that is UL Tested (Underwriters Laboratories) or not. For overall quality assurance it is recommended that customer purchase circuit breakers that have been UL Tested. Be aware that non UL Tested products do not guarantee correct calibration of the breaker. All low voltage molded case circuit breakers which are UL listed are tested in accordance with UL Standard 489 which is divided up into two categories: factory testing and field testing.

  • UL Factory Testing: All UL standard molded case circuit breakers undergo extensive product and calibration testing based upon UL Standard 489. UL certified breakers contain factory sealed calibrated systems. The unbroken seal guarantees that the breaker is correctly calibrated and has not been subject to tampering, alteration and that the product will perform accordingly to UL specifications. If the seal is broken the UL guarantee is void as well as any warranties.
  • Field Testing: It is quite normal for data obtained in the field to vary from published information. Many users become confused to whether field data is flawed or published information is out of sync with their particular model. The difference in data is that test conditions in the factory vary considerably than in the field. Factory tests are designed to produce consistent results. Temperature, altitude, a climate controlled environment and using test equipment designed specifically for the product being tested all effect the outcome. NEMA publication AB4-1996 is an outstanding guide to infield testing. The guide gives the user a better variant of what are normal results for infield testing. Some breakers come with their own testing instructions. Where no instructions are present use a reliable circuit breaker service company.
  • Maintenance: For the most part, molded case breakers have an exceptional track record of reliability mostly due to the fact that the units are enclosed. The enclosure minimizes exposure to dirt, moisture, mold, dust, other containments and tampering. Part of proper maintenance is making sure that all terminal connections and trip units be tightened to the proper torque value as set by the manufacturer. Overtime these connections will loosen and need to be retightened. Breakers also need to be cleaned regularly. Improperly cleaned conductors, the wrong conductors used for the terminal and loose terminations are all conditions that can cause excessive heating and weakening of the breaker. Breakers that are manually operated require only that their contacts are clean and that the linkages operate freely. For circuit breakers that are not used on a regular basis an intermittent startup of the breaker is required to refresh the systems.

As always, it is best to consult a certified electrician to determine exactly what type of circuit breaker is right for your generator application. The factors influencing the safe and proper operation of a power generator and a circuit breaker vary from site-to-site and only a licensed professional can specify the right equipment.


Types of Electric Circuit

There are following 5 main types of electric circuit:

  1. Close Circuit

When load works on its own in a circuit then it is called Close Circuit or Closed Circuit. Under this situation, the value of current flow depends on load.

  1. Open Circuit

When there is a faulty electrical wire or electronic component in a circuit or the switch is OFF, then it is called Open Circuit. In the below diagram you can see that the Bulb is Not glowing because either the switch is OFF or there is fault is the electrical wire.

  1. Short Circuit

When both points (+ & –) of voltage source in a circuit gets joint with each other for some reason then it is called Short Circuit. Maximum current starts to flow under this situation. Short circuit generally happens when the conducting electrical wires get joint of even because of shorting in the load.

  1. Series Circuit

When 2 or more loads (Bulb, CFL, LED, Fan etc) are connected to each other in a series, then it is called a Series Circuit. In a series circuit, if one load or bulb gets fuse, then rest of the bulbs will not get power supply and will not glow. Look at the example below.

  1. Parallel Circuit

When 2 or more loads (Bulb, CFL, LED, Fan etc) are connected to each other in parallel, then it is called Parallel Circuit. In this type of circuit, the voltage capacity of all loads must be equal to input supply. Power of “load” can be different. In a parallel circuit, if one load or bulb gets fuse, then rest of the bulbs will still get power supply and will glow. Look at the example below.



How to Turn on a Circuit Breaker

At one time or another, you’ve had to turn on a circuit breaker. It’s also likely you’ve had to turn one off to replace a switch or outlet, or possibly to put up a new light or ceiling fan. Circuit breakers vary from brand to brand but have the same amperage ratings. In any case, turning a circuit breaker on is so easy, as the Geico commercial touts, that a caveman could do it.

Circuit Breakers and Electrical Safety

Electrical safety always begins with turning a circuit breaker off before performing any electrical work on a circuit or device connected to it. You may say it ends when the project is completed and the circuit breaker is once again re-energized by turning the circuit breaker back on.

You can usually see right away if there is a problem ​by going to the electrical panel and checking for a tripped circuit breaker. Simply open the electrical panel door and search the breakers one by one from top to bottom in both rows of breakers, until you find the troubled circuit. Once located, tape it off so that no one else tries turning on the circuit while you’re working on it. It’s just another safety move that works.

Using a Circuit Breaker

 Circuit breakers are no more than a specialized single-pole switch, the difference being it has three states it can be in: off, on, or tripped (a sort of neutral position). Unlike a switch that is either on or off, the breakers tripped position is a state that allows the homeowner to see that a circuit error has occurred.

To turn on a circuit breaker, simply locate the circuit breaker panel in your home or office. On the face of the panel, you’ll see a door. Open that door and there will be many black circuit breakers with switch handles. These breakers will look wider than taller and most of them are black in color. The switches will be stacked in two rows from top to bottom. On each breaker should be a small window that will show red if the circuit breaker trips. The window is clear when all is well but it will show red when the breaker has tripped.

The breaker switch handles are in the on position when the handles are towards the center of the breaker panel. If they are positioned toward the outside of the panel, they are in the off position. The tripped state will be somewhere in the middle with the window showing red. To reset this state, you’ll need to switch off the breaker before turning it back on.

Be sure to find out what caused the tripped state before resetting the breaker. After fixing the problem, you are ready to check the circuit out by resetting the breaker. If the fault clears, you have indeed corrected the problem. If not, you’ll have to find out where the problem is and continue the steps.

Turning them on is no big deal, but you may want to practice a time or two just in the event you ever have to either reset a tripped breaker or turn one on. That way, you’ll be familiar with what a circuit breaker does and how they function as a disconnect switch.



Well, the answer is, it depends. In general, the answer is you should NOT reset a circuit breaker, unless you know the cause and that cause does not pose a hazard. Circuit breakers are there to protect you, your family, and your home. If a circuit breaker trips, it means there is more current flowing through that circuit breaker than its trip current. So, you must be able to absolutely determine what is causing the excess current through a circuit breaker.

For example, if a 15 Amp circuit breaker trips, it means you have more than 15 Amps of current flowing through that breaker. Now, if you happened to plug in several appliances to that circuit AND you know the draw of the total of those appliances is greater then 15 Amps, then, and only then should you reduce the load on that circuit (unplug things), reset the breaker – only once.

However, most trips of a circuit breaker cannot be isolated that easily. Wiring, like everything else, ages. The insulations’ ability to resist the voltage becomes less and less. Finally, the insulation breaks down and presto – an electrical short. Electrical shorts allow lots of electrons to pass very quickly through the degraded insulation. It’s very much like a pipe that leaks – eventually it can flood your home. Only, in this case, the shorted wire(s) heat up and can burn down your home.

The circuit breaker is your safety valve. But, there’s another inherent and more insidious danger. Circuit breakers, like the wiring in your home, age. In the case of aged circuit breakers, it’s not so much that they trip prematurely, but that they do not trip at all.

Old wires and old circuit breakers are a recipe for catastrophic failure and a fire. In our hot desert environment, circuit breakers have a useful life of approximately 25 years. After that, they must be replaced. Replacing circuit breakers is known as an “Electrical Panel Rejuvenation.”

The moral of all of this, if you are not absolutely sure you’ve unintentionally overloaded a circuit and corrected the overload, DO NOT reset that circuit breaker. Call Eavenson Electric for a safety assessment. We will assure your breakers are functioning properly. If there is a problem, we can correct any faulty wiring or failed circuit breakers.