Hi, I'm Vance and welcome to Repair and Replace.
Appliances are somewhat simple machines, built from of a series of mechanical parts
and basic circuits.
Knowing how these circuits work can help you understand why an appliance isn't working properly.
In this episode we'll learn about the fundamentals of circuits and the 3 main ways that circuits fail.
We'll look at short circuits, ground faults and open circuits.
Now before starting its recommended to watch our "Multimeter & Electricity Basics" video
This is linked in the description below.
A circuit is a series of interconnected paths that carry an electric current.
All circuits will have a power source, wires or conductors, a switch for controlling the
circuit and a device or load that offers resistance to the circuit.
The hot wire or line, carries the power to the load,
and the neutral wire returns the electricity to the power source.
The ground wire is usually green, and is connected to the metal appliance housing.
This provides a safe path to return to the source and will protect against electrocution.
All circuits need a continuous path to return to the source.
This is continuity, or a closed circuit.
If we disrupt this path with with rubber, plastic, or by air in the case of a broken wire,
then the current will not flow as there is no continuity.
This is an open circuit.
And this often happens when a component burns out or fails internally.
Depending on the component, this might affect the whole appliance or just a particular function.
For example if only one stove element stops working,
then it's just an issue with that particular circuit.
Now if all the heating elements are not working,
then its likely an issue with the incoming power.
You can learn more about testing appliance components in the video linked below.
All circuits need to be grounded, and must have overcurrent protection
to prevent electrical fires and electricution.
Your home's circuit breakers protect all downstream circuits and devices
and will trip when the current gets too high.
As well some appliances will have one time fuses rated for a maximum amperage.
This will protect against short circuits.
Short circuits are created when the hot and
neutral wires touch, and the circuit is completed before the load.
In this case the current no longer flows through the entire circuit
and with no resistance, the current rises.
Without any protection, this increased current will cause the wires to heat up,
burn out, and will start an electrical fire.
In a protected circuit the extra current will trip the circuit breaker or will blow the fuse.
Now if an appliance keeps tripping the breaker, then it's likely that there is an internal short.
In this case you'll have to locate and repair the damaged wires or component.
Then the breaker must be reset or the fuse replaced.
A ground fault happens when a hot wire or component
touches the metal housing of the appliance.
The housing is now energized, and the ground wire returns the electricity to the source.
Electricity will always take the path of least resistance.
If you touch an energized housing without a ground wire, you might be electricuted.
If the ground fault happens before the load the circuit is shorted, the current increases,
and the breaker or fuse will blow cutting power to the appliance.
Now if the ground fault happens after the load, there is still resistance in the circuit
so the breaker might not trip.
The appliance might still be functional but this depends on the component affected.
To test if an appliance is shorted to ground you can plug it into a circuit protected by
a GFCI or ground fault circuit interupter.
GFCI's monitor the current between the hot and neutral lines.
If there is even a small amount of current leaking to ground, then the GFCI will trip,
disconnecting power until it's reset.
Components can also be tested for shorts.
If the component has continuity between either terminal and the metal frame,
then it's shorted to ground and will need to be replaced.
Hopefully these videos have made you more comfortable with repairing your appliances.
For more troubleshooting on water heaters, furnaces, and appliances,
then subscribe to our channel.
And if you need help, you can call or visit an AMRE location
to talk with our knowledgeable staff.
Thanks for watching.