IEC (International Electrotechnical Commission) and NEMA (National Electrical Manufacturers Association) are two prominent standards for power cords and electrical connectors, each with its region of influence and specific applications. Here's a comparison of the two standards based on various aspects:

• IEC is an international standard widely adopted by many countries around the world. It aims to create a universal set of technical standards to ensure products can operate in multiple countries without needing different power cords or adapters. Close to 90 countries are currently members of the IEC.
• NEMA is primarily a North American standard used in the United States, Canada, and some parts of Latin America. NEMA standards are tailored to these regions' electrical systems and safety requirements.

In the United States, both IEC and NEMA Standards are widely used.

IEC standards are mainly targeted towards devices used in industrial settings, while NEMA focuses on a wide range of devices, including ones used in residential settings. IEC standards focus on actual performance of electric components, while NEMA is more about the manufacturing process.

Plug and socket designs

Under both IEC and NEMA, the cords and connectors are approved separately.

• The IEC 60320 standard specifies connectors for various devices, from low-power electronics like computers and office equipment to appliances requiring higher currents. Based on voltage, current, and intended use, the designs are categorized into different classes (C1/C2, C5/C6, C13/C14, etc.). The most frequently encountered IEC connectors include C13, C15, and C19. C13 connectors are prevalent in household and office electronics like computers and TVs. C15 connectors cater to high-heat devices such as electric kettles and small network closets. C19 connectors are designed for high-amperage equipment needing constant power, like data servers and rack-mounted hardware. 
• There are no single amperage ratings for NEMA because the plugs are used in very different countries with different amperage standards. The range is believed to be between 15 and 60 amps.

NEMA standards cover a broader range of electrical connectors for residential, commercial, and industrial applications. NEMA configurations are identified by numbers and letters (e.g., 5-15P for a standard 15-amp plug in North America and NEMA 1-15-P for a 2-prong plug). NEMA connectors include locking and non-locking types of designs. NEMA 6-50 and NEMA 14-50 are popular NEMA plugs for high-current applications. NEMA produces straight-blade and locking connectors.

Voltage and current ratings

• IEC standards typically cover a range of voltages and are designed to be compatible with the electrical systems of most countries. For instance, IEC connectors might be rated at up to 250V.
• NEMA standards are designed with the North American electrical system in mind, typically 120V for standard plugs and up to 600V for some industrial connectors. Current ratings vary by design, with residential plugs commonly rated at 15 or 20 amps.

Applications

• Due to its international recognition, IEC standards are prevalent in global markets, especially for consumer electronics, IT equipment, and appliances that are sold internationally. In general, there are many more IEC standards compared to NEMA.
•  NEMA standards are more common in products designed for the North American market, including residential, commercial, and industrial electrical equipment. 

How are cables classified under NEMA?

NEMA standards categorize cables based on their intended use, such as residential, commercial, industrial, or special applications like direct burial, outdoor use, or hazardous locations. This classification includes:

• Portable cords are flexible cables for temporary connections in environments like construction sites.
• Building wire includes cables used within buildings for fixed wiring, including NM-B (non-metallic sheathed cable for residential wiring) and THHN/THWN (thermoplastic-insulated wires for various applications).
• Power cables are designed for transmitting electricity in utility networks, industrial plants, and other large-scale power applications. There are separate classifications for hospital-grade power cords under NEMA. NEMA power cords are specifically designed to withstand short circuits.
• Control and instrumentation cables are for signaling, control wiring, and instrumentation in industrial settings.
• Cables may also be classified by specific performance characteristics defined by NEMA, such as fire resistance, oil resistance, and the ability to withstand extreme temperatures or environmental conditions.

Specific standards and codes

• WC (Wire and Cable) series: This series covers various cable types, including power, control, and instrumentation cables, specifying requirements for materials, construction, and performance.
• UL standards: While not directly part of NEMA, many NEMA cable types are also classified according to UL (Underwriters Laboratories) standards, which provide additional safety certifications and are widely recognized in North America.

How are cables classified under IEC?

The International Electrotechnical Commission (IEC) classifies cables under international standards designed to ensure safety, compatibility, and reliability for electrical and electronic devices and systems worldwide. These classifications are based on various factors, including insulation and sheath materials, conductor types, voltage ratings, and intended applications. Here's an overview of the critical criteria used by the IEC to classify cables:

Insulation and Sheath Materials

Cables are classified according to the type of insulation and sheathing materials used. These materials are chosen for their electrical properties, resistance to heat, chemicals, and environmental conditions. Common materials include PVC (Polyvinyl Chloride), XLPE (Cross-Linked Polyethylene), EPR (Ethylene Propylene Rubber), and others. The choice affects the cable's application, particularly regarding its environmental and thermal performance.

Conductor types

The IEC also classifies cables based on the type of conductor used, which can be solid, stranded, or flexible. This affects the cable's mechanical strength, flexibility, and the ease with which it can be installed. Different applications require different conductor types, depending on whether the installation is fixed or requires frequent movement.

Voltage rating

Similar to NEMA, the IEC classifies cables by their voltage rating, which dictates the maximum voltage the cable can safely handle. This classification helps in selecting the appropriate cable for specific electrical systems, ranging from low voltage (up to 1kV) to medium voltage (1kV to 35kV) and high voltage (above 35kV).

Application and use

• Fixed wiring: Used in buildings and structures for permanent connections.
• Flexible cords: Designed for connecting portable devices, appliances, or equipment that may be moved.
• Instrumentation and control cables: These are used for transmitting signals or controlling equipment operation and are often used in industrial settings.
• Power cables: For transmission and distribution of electrical power. IEC power cords are compact, cost-effective, and great at handling overloads.

Performance characteristics

IEC standards specify performance characteristics such as fire resistance, oil resistance, and suitability for use in different environmental conditions (e.g., UV resistance, water resistance). These characteristics are crucial for ensuring the cable can operate safely and reliably under the specified conditions.

Specific IEC Standards

The IEC publishes specific standards for different cable types, detailing construction, testing, and performance requirements. Examples include:

• IEC 60227: For PVC insulated cables of rated voltages up to and including 450/750V.
• IEC 60502: For power cables with extruded insulation and accessories for rated voltages from 1kV up to 30kV.
• IEC 60754: Test methods for determining the halogen acid gas content of insulating and sheathing materials of electric and optical cables.
• IEC 60320: A standard non-locking power cord with connectors C13, C15, C19.

To buy the right power cord under both NEMA and IEC standards, you should identify the correct plug, voltage, and current for the country of residence and application.

NNC sells a wide range of cables under NEMA and IEC standards.