We all use receptacles every day to power our electronic devices, but how do these work? Hey there guys, Paul here from
TheEngineeringMindset.com. In this video we're going to be looking at how receptacles work, the different parts, how they're wired, as well as the purpose of the ground wire, and we're going to be
using the color coding and terminology for North
America in this video. But if you're from outside this region, you can still follow along
and learn how they work, or you can check out our other videos. Now, we are just covering
the theory in this video, but remember electricity is dangerous and can be fatal. You should be qualified and competent to carry out any electrical work. So if we take a typical receptacle, we're going to find two
neutral terminals on the left, which are silver in color. And then, there'll be two
brass colored hot terminals on the right. We'll also find a green
ground terminal also. Between these respective sets of terminals we have a jumper, but
we're gonna come back a little later in this
video and look at them. Inside the outlet we'll find some tracks which will carry the electricity. The two neutral and the two hot terminals are currently joined
together by the jumper, so both hot terminals
will become energized if either one of the two
were wired into the circuit. We can remove the jumpers
by using some pliers to just snap them off, but
these can't be replaced. By snapping these off we
can isolate the terminals and connect them to different circuits. We'll look at this in detail
a little later in this video. For now, I'm going to leave
these jumpers in place. We can connect this receptacle
into the electrical system by first bringing in our hot wire and connecting that to the hot terminal. Then, we bring the neutral wire in and connect this to the neutral terminal on the opposite side. To make the circuits safe, we bring in our ground wire also. If we now turn on the power, the electricity will
flow along the hot wire and into both the tracks
for the hot terminals. The electricity wants to
reach the neutral terminals to return back to the service panel, but it can't at the moment because there is no path
to complete the circuit. As I said, with the jumper in place both hot terminals are now hot. But, if we remove the
jumper between these two then only the terminal
connected to the hot wire will be energized. In this case, that's the top outlet. Coming back, to complete the circuit we need to plug something
into the receptacle. For this example I'm just gonna plug in a simple light fitting. With the light plugged in,
the electricity can now flow through the hot terminal into the plug. It will then flow along the
cable and into the lamp. From there it will return to the neutral terminal of the outlet, and then return to the service panel and off to the transformer
outside the property where it will complete its circuit. With the jumper in place,
the lamp will also light up if we were to plug it
into the lower socket. But, when we remove the
jumper the circuit is broken and the lower hot
terminal, in this example, is no longer hot and
will not power the lamp. With the jumper still removed, we can still plug the
lamp into the top circuit to complete the circuit
and power the lamp. So, then why would we
want to remove the jumper? One application is when
using switched receptacles like this circuit here, which allows half of the
receptacle to remain hot while the other half is
controlled by a switch. For this we bring the hot wire in and connect this to the wire nut. We then run another hot wire from there and over to the top hot terminal. We can then run our neutral
wire back to the service panel. Of course, we need to also
include our ground wires too. If we power this circuit, then only the top half of
the circuit would be hot. The lower half would have no power. So to connect the lower half to the switch we run a a white wire
from the hot wire nut and take this over to the
lower terminal of the switch. We then need to place
some tape on this wire to warn that it is hot. Then, from the top terminal of the switch we run a black wire over to the lower terminal
of the receptacle. To make the circuit safe we
bring in our ground wire also. And then, when we power this circuit we again get electricity
to the top terminal and we have given it a second path, which leads over to the switch. The switch is off currently,
so electricity can't pass it. But when we flip the switch,
the circuit is now made and electricity can flow
over to the lower half also. If something was plugged in
to either of the sockets, then electricity can flow through and into neutral side to get
back to the service panel. If we flip the switch off, then the power is cut
again to the lower half but the top half will remain hot. Another application is to connect to two different hot wires. If we remove the jumper and then bring in a red hot wire as well as the black hot wire, we can connect the top
half and the bottom half to different circuit breakers. This will spread the electrical
demand over two breakers, instead of just one, so it's less likely to
overload and trip the breaker. So far, I've animated
the flow of electricity using DC, or direct current, which flows in one direction, like the water flowing down a river. I've used this method because it's simple to
visualize and understand. But electricity in your
home flows forwards and backwards because it's
AC, or alternating current. It flows like the tide of the sea, back and forth constantly. But don't worry too
much about this for now. If you want to learn
how electricity works, then check out our
simplified tutorial on that, link's down below. Additionally, we've also
covered split-phase electricity in great detail. Do check this out, link's down below. The next thing I want to briefly cover is the purpose of the
ground wire in the circuit. This wire is an emergency path to try and save you
from an electric shock. Ideally, the ground wire in
the circuit will never be used. But should a ground fault occur, then the wire is on
standby ready to take over. Under normal operating conditions the electricity will flow into your home through the service panel
and circuit breaker, and then into the hot
terminal of the receptacle. If we plug something in, then it could make its way
over to the neutral wire, and then out through the neutral incomer and over into the transformer
outside the property. Again, I'm just animating
the flow of electrons in one direction for simplicity. In the event of a ground fault, which is where the electricity
took an unexpected route back to the source, instead of passing through
an electrical device, for example the hot wire
came into direct contact with the metal casing, then the electricity will
flow through the metal body and into the connected ground wire where it will continue over and it'll either passed
through the neutral or a separated ground busbar, and then up through the neutral wire and over to the transformer. As this occurs, the current
in the circuit is going to increase dramatically,
and almost instantly. In most cases, the sudden
and large rising current is detected by the circuit breaker, which will trip to cut the
power to the individual circuit. The electricity will continue
to flow into the building and into the other circuits
on the service panel. The fault will then need to be corrected, and the circuit breaker flipped again. We've covered ground,
hot and neutral wires, and faults in great detail
in our previous tutorial, link's down below for that. Okay guys, that's it for this video, but to continue your learning, then check out one of
the videos on screen now, and I'll catch you there
for the next lesson. Don't forget to follow us on
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