To answer all the issues you raise would require a book on US electrical wiring. Or several. And a copy of the Code.

The vast majority of outlets in residences in the US are attached to branch circuits that are rated at 15 Amps and 120 Volts. Current practice and code calls for outlets like these

This version is tamperproof, required in many jurisdictions. The non-tamperproof look similar, but the slots do not have internal baffles

You may see different styles, such as Decora, or decorator style, which are functionally identical to basic outlets, but have a rectangular face

20 Amp circuits generally require slightly different outlets (if you are going to draw the full 20 Amps or there is only one outlet on the line) like these

But you can also find the lower 15 Amp outlets on circuits that are properly wired for 20 amps. Obviously 15 Amp outlets are limited in use to 15 Amp appliances, even if they are on a 20 Amp line.

Certain locations, especially where there is a risk of moisture, such as bathrooms, require a ground fault interruper (GFI) type outlet

These also come in tamper resistant and 20 Amp versions and vary like the basic outlets.

All of the above are grounded outlets, required in almost every jurisdiction for new construction and renovations. Some older installations may have ungrounded outlets.

These generally cannot be used except as a direct replacement for an existing one, and even then setting up a properly grounded outlet is preferred and may be required.

All of the 120 Volt outlets require a hot wire (usually black or red) and a neutral wire (always white). Grounded outlets also require a ground wire (green or bare). Outlets can be always live or switched. Live outlets have the hot wire coming directly from circuit without interruption. Switched outlets have the hot wire going through one or more switches before reaching the outlet so that the power can be turned on or off.

All of the 15-20 amp outlets shown above are duplex, that is there are two receptacles for plugs on each. These almost always are bonded together by a strip of metal. When you wire to one, both are energized. This bonding strip can be broken off allowing each of the receptacles on the outlet to be powered separately. This is most often done to allow one receptacle to be always live and one to be switched. This also allows each receptacle to be on a separate branch circuit (for heavy power use).

Some residences use higher amperage outlets for large appliances, such as an electric stove or dryer, and the outlets vary base upon a number of factors. Examples can be seen in the chart linked in the question.

Similarly, some residences use 240 Volts for large appliances and wells, and the outlets also vary considerably, and can be seen on the linked chart.

This is a very brief summary of the type of outlets most commonly seen in US homes. The full range of outlet types and uses is beyond a simple summary. The range of possible switching and wiring configurations also is nearly infinite. But this site welcomes questions on any particular configuration or problem you may encounter, so ask away.

NEMA

首先讓我們花點時間了解一下NEMA是什麼，以及它與插座和電線插頭產品的關係。 國家電氣製造商協會（NEMA）是創建電氣設備標準的標準組織。

每個標準都有一個與之關聯的編號，因此您可能會看到類似 NEMA 5 。這只是意味著，任何符合標準 5 的設備都將顯示標準中描述的特徵。

在處理插座和插頭時，您經常會看到類似的東西 NEMA 1-15 。破折號後的數字表示設備的最大額定電流。因此，在我們的示例中，該設備的額定電流為15安培。

在額定電流之後，您還可能會看到 R 或 P 。這只是表示它是插座（ R ）還是插頭（ P ）（其中“ Plug ”表示實際設備位於末尾）。不要與插座本身混淆，通常被稱為“ 插座”，“ 插頭”或其他一些s語）

NEMA 1

在較老的房屋中，接地導線通常不通向每個插座，因此NEMA 1設備很常見。 NEMA 1-15是最常見的。 NEMA 1設備的最大額定電壓為125伏，由兩個刀片（或插槽）組成，其中一個刀片比另一個刀片稍大。刀片/插槽較小的是未接地（熱）導體，而較大的是接地（中性）導體。

^{NEMA 1-15R sup>}

NEMA 5

在現代家庭中，每個插座都接地線，因此NEMA 5設備很常見。同樣，NEMA 5-15和5-20是最常見的設備。 NEMA 5設備的額定電壓也為125伏，由兩個刀片（或插槽）和一個插針（或孔）組成。刀片/插槽的佈置方式與NEMA 1設備相同，並且針腳/孔是接地導體（不要與接地導體混淆）。

^{NEMA 5-15R-NEMA 5-20R sup>}

NEMA 6

NEMA 6設備不是很常見儘管可以在提供弧焊機，壓縮機或其他類似應用的車庫中找到美國的住宅應用。這些設備由兩個未接地（熱）導體的刀片/插槽和一個作為接地導體的銷/孔組成。因此，這些設備的額定電壓為250伏，並且不不能提供125伏的電壓。

^{NEMA 6-20R-NEMA 6-30R sup>}

NEMA 10

在常見接地導體之前，NEMA 10設備已用於大型設備。 NEMA 10-30通常用於電動干衣機，而NEMA 10-50用於電動範圍。 NEMA 10設備的額定電壓為125/250伏，由3個刀片/插槽組成。兩個刀片/插槽；通常標記為 X 和 Y 的導體是不接地的（熱）導體。第三個刀片/插槽是接地的（中性）導體，通常標記為 W 。

^{NEMA 10- 30R-NEMA 10-50R sup>}

NEMA 14

當接地導體變得普遍時，NEMA 14設備取代了NEMA 10設備。這些設備的額定電壓也為125/250伏，並具有3個刀片/插槽，但是增加了用於接地的插針/孔。同樣，它們有兩個未接地（熱）導體的刀片/插槽（ X ， Y ），一個刀片/插槽是接地（中性）導體（ W ）和作為接地導體的引腳/孔（ GND ）。

NEMA 10和NEMA 14器件能夠提供125伏電壓，並且250伏這是由於電力在美國的普遍分配方式所致。

^{NEMA 14-30R-NEMA 14-50R sup>}

分配

在美國，最常見的分配系統是單相分配系統。雖然可以找到三相配電。

120 / 240V

在分相繫統中，電力以高壓從發電設備傳輸到本地配電站。使用降壓變壓器將高壓電降壓至〜240伏。變壓器在次級繞組上有一個中心抽頭（這就是為什麼它被稱為“ split-phase ”）的原因，它允許提供120伏的電壓。為家庭供電的電纜將由3條導線組成。兩根未接地的（熱）導體，它們之間的電壓為240伏。還有一根接地的（中性）導體，它與任一根未接地的導體之間的電位均為120伏。

208Y / 120

在3-pahse系統中，將為建築物提供4條導線。三個不接地（熱）的導體，它們與任何其他不接地的導體之間的電勢均為208伏。一個接地的（中性）導體，與任何未接地的導體之間具有120伏的電勢。每個未接地的導體與任何其他未接地的導體異相120°，這就是為什麼它被稱為“ 三相”系統的原因。在美國，這是一種不常見的住宅分佈形式，但可以在某些地方找到（在農村地區更為常見）。

You should probably ask for advice from the salesperson at the store if you are buying a major appliance, and maybe take a picture of your house's actual outlet. Houses built before 1996 use (generally) the 10-30 and 10-50 type for dryers and ovens respectively, whereas houses built after 1996 use 14-30 and 14-50. I believe some microwaves and refrigerators require a 20 amp circuit, which would use a 5-20 type plug. And of course the most common type of outlet is a 5-15, which @bib provided many pictures of in his answer, and is what Americans think of when they think of an ordinary electrical outlet.

Other than that, most of the types of plugs you see in the diagrams you linked are mainly relevant for industrial usage.

The reason a 4-prong plug is needed for ovens and dryers is because the 240V circuits used for dryers and ovens actually have opposite phases of 120V on each of the two hot pins (to get 240 across them) rather than 240V from a single hot pin to neutral, and the ground wire was used as a neutral in older appliances requiring 120V for some components (or maybe it's more accurate to say it's a neutral and was used as a ground). See split-phase.

So, the key thing to find out when buying a house is if it was built before 1996, and if so if it has been rewired to the new standard. If the house was built before 1974, it may also have two-prong 120V outlets (NEMA 1-15). If it was built in the 1970s or earlier, you should probably also find out if it has aluminum wiring, though wiring is technically outside the scope of your question.

房屋中的絕大多數網點將是5-15種。在典型的美國房屋中，與眾不同的將是電爐和乾衣機。不幸的是，已經對代碼/做法進行了幾處更改，很難說出您在任何一所房子中對於那些特殊的高壓/安培插座所能找到的或可能找不到的東西。如果不確定，請諮詢電工以獲取更多信息。

以下是您的問題答案的相反：

插頭和插座的數字博物館， http： //www.plugsocketmuseum.nl，您可以在其中找到當前的和歷史的套接字，足以使數小時的娛樂活動變得混亂。有關現代佈線的實用建議，請參見其他答案。