The National Electrical Manufacturers Association (NEMA) is a trade association for the electrical manufacturing industry involving manufacturers of electrical goods, electrical equipment, and imaging equipment in North America.
The association was established in 1926 and currently has over 400 member organizations that are involved in:
- Generating use of electricity
- Transmitting use of electricity
- Distributing the use of electricity
- Controlling the use of electricity
- Facilitating the use of electricity
The members of NEMA facilitate the distribution and use of electrical appliances in:
- Residential settings
- Commercial settings
- Industrial settings
- Institutional settings
- Medical settings
NEMA sets and enforces standards used to rate testing and performance, manufacture, and the application of various electrical equipment with the objective of minimizing risk to users, increasing the compatibility of electrical components, and simplifying product development.
Apart from the regulation of electrical products and standards, the NEMA represents and protects the interests of its members by lobbying with various levels of government and industry regulators.
- The association ensures the inclusion of their input in:
- Local building codes
- National and local energy and installation policies,
- International trade agreements
The association also conducts:
- Market research and analysis
- Publishing findings
- Making recommendations on the future of electrical manufacturing and installation.
The NEMA publishes standards and articles that communicate the organization’s position on various matters relevant to its operations.
How the NEMA sets standards for industrial products
The NEMA establishes standards for the manufacture and installation of electrical components, with a focus on commonly used components as follows:
Connectors
Power connectors are the components used to facilitate electronic devices’ connections to the power outlet. These carry either AC or Direct current and the most common are two-pronged and three-pronged connectors common in households.
Currently, connectors in the US range between 15 and 60 amperes with voltage levels of between 125 to 600 volts. These vary in configurations depending on the shape, width, position, blade width, and measurement. To create consistency in the industry, NEMA standards have identified various pin positions for plugs based on the amperage and voltage.
Plugs, Power cords, and Receptacles
The NEMA standardization uses numbers to code the different components with the first number being the plug configuration which indicates the wires, poles, and voltage. The second number indicates the ampere rating with a clarification for either plug or receptacle indicated by either “P” or “R” respectively.
The connectors can either be locking or interlocking to prevent accidental disconnection of the plug or receptacle. Locking connectors are mostly used in industrial use where the connection is expected to be permanent or semi-permanent. Power cords are similarly designed to meet various amperage and voltage uses with insulation covering the copper wires. The capacities of the wire are also influenced by the length of the wire which affects amperage and the thickness of the wire which is determined by American Wire Gauge (AWG).
Enclosures
An electrical enclosure is a box intended to protect electrical equipment and connections to avoid electrical shock. It is made from a non-conductive material such as plastic, steel, or aluminum and is designed to withstand environmental hazards.
The NEMA standards contain thirteen different enclosures rated according to the conditions where they can be used based on the protection that they offer.
According to the different classifications, the enclosures protect against:
- Contact
- Dirt
- Ice damage
- Dust
- Explosion
Some enclosures have power disconnection features to prevent power damage in the occurrence of an adverse event.
Safety features
One of the core objectives of the NEMA is to ensure the safety of electrical equipment to both electrical experts and ordinary users. To meet this objective, NEMA requires the use of set safety standards by both manufacturers, users, and during maintenance. To protect receptacles from tampering, NEMA requires the use of tamper-resistant shutters which are loaded with a spring to close off openings.
NEMA also requires the use of circuit interrupters which protect against electrical shock and fires when an arc fault is created by the flow of current on an unplanned path. Similarly, the association encourages the use of surge protectors which protect appliances from energy surges of voltage.
A surge protector blocks or reduces the flow of current to the appliances. For receptacles that are intended to be used outside, the association requires the use of weather-resistant receptacles which protect the outlet from:
- Corrosion
- Damage
- Hazardous weather conditions
The most important safety feature used in electrical connections and appliances is the use of color-coding to easily identify wiring as either ground, neutral, or power line. Wire lines connected to power are further classified as either single-phase or three-phase.
