Why Some Devices Have Two Prong Plugs And Others Have Three

Why Some Devices Have Two Prong Plugs And Others Have Three


Hello, I’m Daven Hiskey, you’re watching the
TodayIFoundOut YouTube channel. In the video today, we’re looking at why some
devices have two-prong plugs and others have three. To provide a source of power, electricity
must flow in a circuit. (Although, you might be surprised to learn
the net velocity of the flow of the electrons is actually quite a bit slower than a turtle,
which you can learn all about in this video.) In a typical American outlet, the circuit
is comprised of a right vertical slot connected to the “hot” wire and a larger left vertical
slot connected to the “neutral” wire. The plugged in device itself (the load) completes
the circuit, with power flowing through it. So what’s the third prong needed for then? This third prong is the ground. Both the neutral and the ground are connected
to an earth ground in the main breaker box in your home. The difference between the two is that the
neutral completes a circuit with the hot wire and normally carries some amount of current
(which is why it’s insulated), while the ground does not normally carry any current
whatsoever and is not connected to the circuit at all (unless something has gone wrong). It simply is used to connect the external
conductive parts of the device to the earth and, thus, in normal operation is completely
unnecessary. This is why you can use a 3-prong to 2-prong
plug adapter to bypass having to use the ground line and the device will still work just fine. So why have both a neutral and a ground when
they both ultimately just tie to the earth ground bar in the main breaker box? Among a few other benefits, this is primarily
so that if something should go awry with the device, like a stray hot or neutral wire coming
into contact with the outer conductive parts of the device (for instance, if the insulation
wears away or a wire comes loose), you don’t die or get seriously injured if you touch
the device and it’s plugged in. You see, absent a separate ground in such
a malfunction, once you touched the conductive bits of the device, you may become the path
to ground and a surge of electricity would flow through you until ultimately tripping
the breaker in your breaker box. With the separate ground, the electricity
simply surges through that wire until the breaker is tripped, cutting off power to that
line when the surge is detected. This not only helps to ensure you don’t
get shocked, but also reduces the chances of a fire starting due to the short via making
sure the breaker is tripped immediately after the short happens. So what about the devices that lack this third
ground prong? How is this safe? They (usually) have at least two layers of
insulation between the conductive components of the device and any part of the device you
can touch. To achieve this cheaply, the outer casing
of these devices are often made entirely of plastic or some other non-conductive material. So thanks for watching this video, if you
liked it, please click that like button below and consider sharing it with anyone you think
might be interested. And of course if you’re new to TodayIFoundOut,
don’t forget to click the subscribe button to get more interesting videos like this. We release a new video almost every single
day, so you’re sure to find something you find interesting. Thanks for watching.

43 comments / Add your comment below

  1. People nerdy enough to watch this video…are also nerdy enough to get annoyed when someone says "turtle" when they mean "tortoise" .
    So what is the difference? Hey! Subject of next video!

  2. To be completely honest I wish all the videos on this channel were done by this guy…for some reason he is very fun to listen to and watch. Not saying I don't like British accents but I find this guy better for some reason. Please have him make more!

  3. Tbh I came here because I wanted to know why the UK and Ireland use 3 instead of 2 plugs. Seems like no other country uses 3

  4. The title is confusing, mainly due to its wording. It suggests the topic on the number of plugs with prongs rather than the number of prongs each plug bears. A hyphen is missing: '(…) have two-prong plugs (…)'. Note also that the ellipsis at the end is awkward, and even more suggestive towards the idea of the number of plugs, not prongs. Therefore: 'Why Some Devices Have Two- and Others Have Three-prong Plugs'.
    But I DID enjoy the video itself!

  5. I knew about the ground but what are those outlets that have one t-shaped vertical slot for. I have never seen a t-shaped plug.

  6. Bonus Fact, the Metal ring attached to the 3 to 2 prong converter is there so It can be attached to the screw in the center of the outlet and act as a ground.

  7. In Germany we only have 2 round Ones…but there is a frame on Metal between the Rubber and its connected to the Earth Wire.
    So we still have everything grounded just not a extra prong for it

  8. 1:35 Sometimes it throws a circuit breaker, sometimes it doesn't.

    It only takes 0.1 amps to kill a person. That is not going to trip a 15 amp circuit breaker.
    Yes, there are Ground Fault Interrupt breakers which should stop you from being killed. In America, according to code, in new houses, they need a GFCI outlet in the kitchen, bathrooms, and outside. If you are anywhere else in the house, good luck. If you are in an older house that was grandfathered in, really good luck. And if your are a house built in the 1950's, you might not even have that third ground connector…

    And then, the GFCI that is there to save your life may be the cheap $6 builder's special. And GFCI breakers and outlets go bad.

    As I said; Sometimes it throws a circuit breaker, sometimes it doesn't.

  9. Not all devices work "just fine" without a proper ground. Many devices, particularity those working with small signals, use the earth ground as a clean reference potential. The neutral, carrying current, is too noisy to be used as a clean reference. So the device may still "work" with a two prong adapter but may have trouble detecting weak signals and so be working in a degraded manner. The weak shortwave station that you can hear while plugged into ground might be covered with too much static after using a two prong adapter.

  10. All the info in this video is good, but there are details that if they had been included
    would make for both better understanding and greater accuracy.

  11. A ground connection is also used for static discharge to protect electronic controls. Not having a ground connection is a way to void your warranty, and get a manufacturer to refuse to fix their product.

  12. Uhhhh I love this channel, and I hare to be this mean, but I honestly can not stand this guy his voice is quite annoying

  13. Ready to watch another fun fact video? Then check out this video and find out Why Zippers Have YKK On Them:
    https://www.youtube.com/watch?v=0tJh0VrKPVc

  14. Double insulated appliances can use 2 prong plus as there is no possibility of an internal short endangering you, usually have a complete plastic case with any metal being insulated. And may not have the wide prong on the plug so they can safely be plugged in either way.
    A 3 prong appliance has a metal case that is grounded to the 3rd prong in case of a short circuit that could connect the hot side to the metal case and trip the circuit breaker. No grounding of the metal case and it is an electrocution danger.

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