Fault Detecting Over-current Protection Devices

Spaying into the activities of an interrupter reveals some amazing things they do to protect you and your properties.

Definition

An interrupter is an electronic device with some mechanical parts designed to automatically stop/interrupt the flow of current when it perceives a potential harm to lives and properties.

The circuit breaker

The traditional form of an interrupter is the circuit breaker. You may not see them often because they are installed in a breaker panel (distribution board) which is often closed.
The traditional circuit breaker like every other interrupter is a switch that is not manually operated. In the case of a circuit breaker, it watches over the state of your home's electrical system. If for any reason there is a sudden increase in the flow of electric current, an increase that could course some damage to your electrical appliances, the circuit breaker should detect this within some mili-fraction of a second and switch itself off to prevent such a current from getting into your home. The quantity of current that will trigger the switch-off is defined on the breaker.
A sudden rise in current is not the only possible problem that may occur in electrical system in your house. But that is all the old circuit breaker can protect you from.

_{interrupters of different ratting mounted in a breaker box}

Modern Interrupters

Welcome to the world of advance circuit interrupters like the Arc-fault, Ground-fault and dual function interrupters.

AFCI

The Arc Fault Circuit interrupter are able to detect an arc wherever in occurs in the house electrical system. An Arc resembles a partial contact, it's a situation where a switch is in an off position but the terminals are still so close to each other that power can still jump across the very small gap between the separated terminals.
This situation often behaves like a very high resistor and will result in a build-up of heat which can set your home on fire. The AFCI can identify such a fault and automatically trip-off.

• Do not connect a pressing iron to a socket protected with an Arc Fault Circuit interrupter, the regulator in the iron will trigger an arc fault. The interrupter will detect it as a series arc. Arc and partial contacts are responsible for most fires that start from switchovers and cutout plugs. If you are not at home when a real partial contact or arc starts, the AFCI can take care of that.
  

• When due to the use of poor insulators, the live and neutral cables are having some cross-talk, an Arc Fault Circuit interrupter can detect it an trip off. This situation is best described as a parallel arc. The wire starts getting hotter till it melts and the cables meet and sparks, it's often a leading curse of electric fires.
  

_{A Combination Arc Fault Circuit interrupter ( CAFCI ) can detect both types of arc faults. Try not to confuse a CAFCI with a DF(AFGF) circuit interrupter.}

GFCI

A Ground Fault Circuit interrupter can detect faults to the ground. We have live neutral and ground cables in a standard wiring system. The G.F.C. Interrupter calculates and confirms that the incoming power on the live cable should be equal to the out going power on the neutral cable. If for any reason the incoming and outgoing power are not Balance, then the electric flow has found another Path which is often dangerous.
What could trigger a reaction from a GFCI

1. The life cable is touching an earth cable or the metal housing of the breaker box, diverting power into it, which could electrocute someone.
2. A neutral cable somewhere in the installation is connecting to an earth cable or a breaker box housing which is equally dangerous, resulting in power being diverted into the ground
3. Someone, somewhere in the house is suffering an electric shock. Power is diverted away from the system through the electrocuted victim.

In all three cases, the GFCI will trip off in less than a tenth of a second to prevent any further damage.

AFGFCI

The Arc function Ground function circuit interrupters are able to detect and manage both ground function and Arc function situations. They are mostly used in bathroom, kitchen and places where you may likely be wet when getting in contact with electronic devices.

Am I still protected?

If you are asking that question, it is just fair that you ask to be sure if your fault detecting and over current Protection Devices is still functional. The test is very simple. If you are having a phobia for electricity, call on someone and ask the person to press the yellow test button on your Protection Device.
This test should be done when the power is on, so calling an electrician may be a good idea.
What will happen when I press?
Be ready as the switch will trip off once the button is pressed. The sound it makes may startle you if you are not ready for it. Note that all devices under the protection of the Interrupter will loose power when it trips off. You will have to push it to the on position after the test.
What if nothing happens?
There are a few possibilities
• There is no power at the time of the test...
• The device is faculty...
• The device was not probably installed...

Conclusion

Having a better understanding of this protection devices should help you understand why the sockets in your home are labeled. A socket for ironing, for fridge for Air conditioner, for regular appliances.
Giving us good reasons to always use the correct sockets because they are connected to specific Fault Detecting and Over-current Protection Devices.

Spaying through the hole in the breaker box I can see an electronic device who's hame has 11 letters starting with latter I and once closed in the breaker box, you are likely not going to see it if you are not an electrician.

Interrupter are truly there to protect your life and properties

@patjewell

Picture Credit

All picture were captured and edited by me