NEMA connector
NEMA plugs are a series of different types of power plugs named after the National Electrical Manufacturers Association , which are mainly used in America, especially the USA , Canada and Mexico , as well as parts of Asia (China, Japan, Thailand, Philippines, partly Vietnam). The number of contacts and assignment is primarily designed for the single-phase three-wire network common in these countries . With a few exceptions, NEMA plugs are not used in Europe.
NEMA plugs are designed for voltages from 125 V to 600 V and permissible currents from 15 A to 50 A. There are different connector types for the various applications, which differ in the number, shape and arrangement of the contacts and in the mechanical shape of the connector housing. Their structure is specified in the ANSI / NEMA WD – 6 standard .
Types
The different types are distinguished by a number after the designation. One of the standard plug are available in a version with a accommodated in the socket rotatable locking ( English lock ), which by the letter L is marked. The purpose of the lock is to prevent the plug from accidentally slipping out of the socket by pulling on the plug. The individual plugs are further subdivided into variants for different permissible currents.
With its simple two-pole variant without earthing connection NEMA-1, also known as type A designated, there are different versions for single-phase AC voltage as NEMA-5, also known as type B , respectively. NEMA-5 are most of the power plugs in use in the USA, the operating voltage is 120 V at a power frequency of 60 Hz. The NEMA-6 series plugs are intended for larger loads such as electric ovens or dryers. In the single-phase three-wire network, double the voltage of 240 V is available for those consumers. Three-phase alternating current (three-phase current), as in Europe, is also available in North America for larger electricity customers, but it is unusual, especially for end customer connections. However, there are some special NEMA plugs such as NEMA-L15 that are intended for use with three-phase alternating current.
Some of the popular NEMA connectors are shown below.
NEMA-1
The NEMA-1 connector, also known as Type A , has two flat, live contacts that are parallel to each other, 12.7 mm (1/2 inch) apart. The contacts are 6.35 mm (1/4 inch) wide, 1.524 mm (0.06 inch) thick, and 15.875 to 18.256 mm long. The plugs are used for small consumers such as radios and in North America they are usually operated at 120 V and 60 Hz. In Japan they are operated with 100 volts, in China and the Philippines also with 220 V.
NEMA 1 plugs can be used in NEMA 5 receptacles.
NEMA-5
NEMA-5, also known as Type B , has two flat live contacts that are parallel to each other. Size and spacing are identical to NEMA-1. An additional round contact pin arranged in an offset manner serves as a protective conductor contact . This arrangement ensures that the plug is protected against polarity reversal. Like NEMA-1, the system is usually used for small consumers with 110–127 V AC voltage and 60 Hz line frequency.
The protective conductor contact is longer than the two live contacts and is therefore connected in front of them when plugged in and only separated after them when unplugged.
The NEMA 5 sockets also have child-proof versions that prevent an object from being inserted into one of the two flat, live contact openings. A spring mechanism only releases the openings when both pins of the connector are inserted at the same time. In Canada and parts of the United States, these child-resistant outlets are mandatory in new and renovated homes.
NEMA-6
NEMA-6 represent a series of “power plugs” that are designed for 208–240 V and up to 50 A and allow the operation of larger loads such as heating and air conditioning devices, clothes dryers and kitchen appliances or agricultural machines with increased power requirements.
Whether such sockets can be found in an (American) household can usually be seen from the associated mast transformer .
Travel adapters for this type of socket are uncommon because of the size and the necessary fuse.
NEMA TT-30
The NEMA TT-30 connection (TT stands for the English term travel trailer ) is a 120 V 30 A standard for leisure vehicles, also known as the RV 30. The TT-30R socket is typically found in almost all RV parks in the United States and Canada, and except for the largest RVs made since the 1970s, this plug is used to connect to power supplies.
The appearance of this connector is sometimes mistaken for a 240V rated NEMA 10 connector. However, the NEMA TT-30 is a 120 V connector. In contrast to NEMA 10 connectors (where the angular arrangement of the contacts is 30 ° and 60 °, respectively) the hot and neutral blades are angled 45 ° from the vertical and 90 ° to each other. Also, the plug is slightly smaller than a NEMA 10 and larger than the usual 5-15P plug. The ground pin is round, like straight NEMA grounding devices. In relation to the picture, the orientation is the same as that of the NEMA 5 male and female with the neutral blade on the bottom right.
Adapters are available with a TT-30P plug on one end and a 5-15R or 5-20R socket on the other. When a power cord is detachable from a motorhome, an L5-30P is typically used on the RV end of the cord.
See also
- Commons : National Electrical Manufacturers Association (NEMA) connectors - collection of images, videos, and audio files
- Country overview connector types, line voltages and frequencies
Individual evidence
- ↑ ANSI / NEMA WD – 6 ( Memento of the original dated February 4, 2012 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. , Standard, accessed on March 21, 2012
- ↑ National Fire Protection Association ( page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.
- ↑ Electrical Safety Foundation International ( page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.
