The amperages of a standard electrical outlet in the USA and Canada are rated at 15 amps and 20 amps. They typically operate on 120 volts, which is the standard outlet voltage in the United States. Here are how outlets are ranked in other countries:

• In the UK, standard outlets are usually rated at 13 amps, operating at 230 volts.
• In most other European countries, outlets typically provide 16 amps at 230 volts.

• In Australia, standard outlets generally are rated at 10 amps operating at 230 volts.

15-amp residential outlets in the USA are common for bedrooms and other general areas, while 20-amp outlets are more common for kitchens, garages, and bathrooms. The National Electrical Code (NEC) suggests a maximum load of 80% under continuous use for 15-amp outlet is 12 amps. For a 20-amp outlet, the continuous load is 16 amps.

How can I tell if my outlets are 15 amps or 20?

• 15-amp outlets have two vertical slots and a round hole centered below them for the ground. The two vertical slots will be the same size.
• 20-amp outlets have a similar configuration with two vertical slots and a round grounding hole. However, one of the vertical slots will have a small horizontal slot added to it, forming a T-shape. This T-shaped slot is designed to accommodate the 20-amp appliance plugs.
• The safest method to confirm the amperage of your outlets is to check the circuit breaker that controls the outlet. Breakers are typically labeled with their amperage on the switch itself. So, If the breaker is labeled 15 amps, the outlets it controls should be rated for 15 amps. Similarly, if labeled 20 amps, the outlets are likely rated for 20 amps as long the wiring and outlets are appropriately matched to the breaker capacity.
• Sometimes, the back of the outlet may have a label or stamp indicating its amperage rating. This can be checked by carefully pulling the outlet out from the wall (after ensuring the power is completely turned off at the breaker.
• The wire can also indicate which outlet it is. If you see a 14 AWG wire after removing outlet from the box, it's a 15 Amp outlet. If the wire is 12 AWG, it's a 20-amp outlet.

Standard height of switches and outlets

•  The typical height for installing wall outlets is about 12 to 18 inches from the floor to the bottom of the electrical box. This measurement is taken to the bottom rather than the center of the box to accommodate standard plug lengths and make it easier to reach behind furniture.
•  In kitchens and bathrooms, outlets are often placed just above the countertops to be easily accessible without moving appliances or items.
•  For accessible design, outlets should be no less than 15 inches from the floor to the center of the receptacle.
• The common height for light switches is generally between 48 and 52 inches from the floor to the center of the switch box.
• For accessibility, light switches should be installed no higher than 48 inches from the floor to the top of the switch in public buildings (some homes follow this guideline to accommodate residents with mobility issues).
• In children rooms, switches might be installed lower to allow children to reach them more easily. 

Do I need a 15 or 20-amp outlet?

• 15 amp outlets are sufficient for most household lighting, electronics, and small appliances. This includes TVs, computers, lamps, and small kitchen appliances.
• 20 amp outlets are used for heavier-duty appliances that draw more power, such as large kitchen appliances (microwaves, toasters), power tools, and equipment in garages or workshops.
• If the circuit is intended for general use with multiple small appliances or devices used simultaneously, a 15 amp circuit with corresponding outlets is typically adequate.
• For circuits intended to serve a single appliance or high-current appliances, a 20 amp outlet is necessary. This is common in kitchens, laundry rooms, and other areas with heavy-duty appliances.

What are some non-standard outlets in the USA?

240-Volt Outlets

Unlike in Europe, where it is a standard residential outlet, in the USA, these are typically used only for high-power appliances such as ovens, dryers, and air conditioning units. They come in various configurations depending on the appliance and its amperage requirements:

• NEMA 14-30: Commonly used for clothes dryers, delivering 240 volts at 30 amps.
• NEMA 14-50: Used for ranges and ovens, providing 240 volts at 50 amps.
• NEMA 6-50: Used for welders and large machinery, supplying 240 volts at 50 amps without a neutral line.
• NEMA 10-30 and 10-50: This is an older style 3-prong plug without a dedicated ground prong (two hot prongs and one neutral prong). These were typically used for dryers and ranges in older installations. Modern codes require a four-prong plug that includes a ground for new installations (NEMA 14 series).

USB Outlets

These outlets include one or more USB ports alongside traditional AC receptacles, allowing devices to be charged directly via USB cable without needing a plug-in adapter:

• USB Enhanced Outlets: They provide USB-A, USB-C, or both types of ports for charging smartphones, tablets, and other devices.

Smart Outlets

Connected to a home automation system or controlled via Wi-Fi or Bluetooth, smart outlets allow remote control of the connected device:

• Wi-Fi/Bluetooth Outlets: Can be programmed or managed via apps to control lighting, appliances, and power usage.

Twist-Lock Outlets

Used in industrial applications and for high-power appliances where a secure connection is critical to prevent accidental disconnection:

• NEMA L-series: These include various configurations like L5-30 L14-30, which are used for portable generators, RVs, and commercial equipment.

Hospital-Grade Outlets

These are designed for medical settings and have additional construction features that enhance reliability and safety:

• Medical Grade Receptacles: Identified by a green dot, they are designed to handle more frequent and critical use with greater durability.

Weather-Resistant and Tamper-Resistant Outlets

Specially designed for outdoor use or in homes with small children:

• Weather-Resistant: Have protective covers that guard against moisture and dirt.
• Tamper-Resistant: Include a built-in shutter mechanism to prevent foreign objects from being inserted.

What are the plugs for most common 15 amo and 20 amp standard outlets?

In the United States, the plugs and receptacles for 15 amp and 20 amp circuits are standardized to ensure safety and compatibility across different electrical devices and systems. Here’s a breakdown of the most common plugs and their corresponding outlets for both 15-amp and 20-amp configurations:

15 Amp Plugs and Outlets

• NEMA 5-15 is the standard household plug used across the United States. It features two parallel flat prongs and a round prong for grounding.
• The corresponding outlet for a NEMA 5-15 plug is also known as a duplex receptacle. It accommodates the two flat prongs and one round ground prong of the NEMA 5-15 plug. These outlets are almost universally available in residential and commercial buildings.

20 Amp Plugs and Outlets

• NEMA 5-20 plug differs slightly from the 15 amp plug. It has one horizontal blade and one vertical blade (forming a sideways T-shape), plus a round grounding prong. This configuration ensures that 20 amp plugs do not fit into 15 amp outlets, preventing the risk of overloading a 15 amp circuit.
• The NEMA 5-20 outlet can accept NEMA 5-15 and NEMA 5-20 plugs. It features a T-shaped slot for the neutral blade, a vertical slot for the hot blade, and a hole for the ground prong. This design makes it versatile, as it can safely accommodate appliances requiring either 15 or 20 amps.

Cables for Standard Outlets

• NM-B Non-Metallic Sheathed Romex® Cable -  most popular for indoor
• UF-B cables - most popular for indoor outlets
• MC metal-clad cables - commercial applications
•  Copper and aluminum THWN - in conduit for garages