What’s The Difference Between UL And IEC Standards?


Post By: Ryan King On: 22-10-2024 - Automation & Control - Manufacturing


When choosing or specifying devices and equipment, it’s easy to get confused when facing two different rating types. These are certification standards applied by two major international organisations: the International Electrotechnical Commission (IEC) and Underwriters Laboratories Inc. (UL). It’s important to recognise what each standard means and how they both relate to the products and equipment you’re using.

Who Are The IEC And UL?

The IEC was founded in London in 1906 as a response to the greatly increasing use of electricity. It was felt that there should be some means of establishing standards in the new technologies, to ensure their effectiveness and safety. Later it incorporated electronics too. 

UL is a safety science company known worldwide for third-party certification. Founded in 1894 in Chicago, it’s America’s oldest and biggest independent testing laboratory. All the latest technologies and products can be rated for safety before they’re released for sale. Its scope is very wide and spans an annual testing of 22 billion different products. These range from consumer electronics, medical devices, alarms and security equipment to robotics and lasers.

Difference In Standards Between IEC And UL

IEC

These two sets of standards differ significantly in that IEC standards rate only electrical and electronic equipment for minimum safety requirements. Their Ingress Protection (IP) ratings are internationally recognised so that equal standards for equipment safety can be relied upon in all countries and markets. UL standards are very comprehensive, rating application and product safety in full technical detail. Testing is extensive and rigorous, and audits may also be carried out to ensure compliance.

UL are responsible for field acceptance and general third-party certification as well as just standards, so they’re empowered to carry out site inspections of manufacturing facilities. The UL also monitor compliance more strictly than the IEC, to ensure that all equipment is manufactured in accordance with the specified framework and certification conditions. For these reasons, obtaining a UL listing is often more expensive than getting IEC approval.

Some Well-Known Examples Of IEC Ratings

Some of the best-known and commonly recognised IEC ratings include IP ratings, and ratings for electrical voltage and current.

IP Ratings

The IEC’s IP ratings are a set of numerical codes designed to distinguish how resistant an electrical/electronic enclosure may be against the intrusion of contaminants. The numbers have two parts – the first depicting what protection is offered against dust; the second against liquids. For instance, an IP rating of 37 depicts a protection level of 3 against dust and 7 against liquids. 

Voltage Ratings

The IEC also rates electrical voltage levels, dividing them into low, medium, high and ultra-high classifications.

  • Low AC voltage is defined as being up to 1,000 volts

  • Medium AC voltage is defined as 1,000-35,000 volts

  • High AC voltage is defined as 35,000-230,000 volts

  • Ultra-high AC voltage is defined as 230,000 volts and above

A typical IEC voltage standard is IEC 60038, which specifies a medium voltage level rating that can be applied to many devices. Low voltages are common in equipment like switchgear and come under the general umbrella of IEC 60947. High and ultra-high voltages are typically used in power transmission applications and large-scale or long-distance electrical operations. Ultra-low AC voltages are rated at less than 60 volts, providing additional safety in more hazardous or sensitive situations.

Current Ratings

You’ll also find IEC standards applied to electrical items that provide guidance on appropriate currents. Components like fuses and circuit breakers carry an IEC standard certification, to ensure that they can support the appropriate current levels. Some of the most common IEC standards for rating current include IEC 60065 and 62368 for audio and video equipment and IEC 60320 for electrical connectors such as power cords. 

Some Well-Known Examples Of UL Ratings

UL ratings are applied to a wide range of equipment and consumer products, especially in the North American market. They demonstrate that an item has passed rigorous testing and meets clearly defined standards for performance and safety. The UL certification system has three tiers: Classified, Recognised and Listed.

  • UL Classified is the lowest rating and signifies that equipment has undergone a single test, with specific requirements, under limited hazard and testing conditions.

  • UL Recognised is usually applied to contributory items, such as parts or machinery required to make other products. The rating can signify, for example, that machinery is safe for workers to use on an assembly or production line.

  • UL Listed is the most common of the UL standards, applied to stand-alone items. It demonstrates that, after rigorous UL testing, the product has met their requirements for performance and safety and can withstand electric shock and fire risks. A UL Listed certification indicates that a product can handle normal daily wear and tear.

How UL And IEC Standards Differ

The UL and the IEC have fundamentally different approaches to safety standards, with UL testing a more comprehensive range of factors like mechanical hazards and fire resistance as well as electrical safety. Their scope extends beyond purely electrical items to include such things as furniture, building materials and PPE. IEC standards are concerned solely with international baseline safety standards for electric-related products, including electronic equipment.

A UL listing signifies a more rigorous testing process that includes in-depth product testing, factory inspections and follow-up audits. IEC Approval generally involves testing by accredited laboratories and localised certification. Because its scope is international, a Nationally Recognized Testing Laboratory (NRTL) can take care of this in the country of manufacture, with certification of IEC standards implemented by national organisations.

The recognition of UL standards is generally limited to North America, although some UL Listed products might be more widely approved. IEC standards are globally recognised, although national safety requirements might be imposed as well by individual countries. Sometimes, an item might have both UL and IEC ratings, but it’s more likely to have one or the other. This is because UL standards are applicable primarily in North America – though also found elsewhere – while IEC standards are applicable globally.




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