6 most important standards in electrical engineering
In electrical engineering, standards play a central role in ensuring the reliability and safety of devices and equipment. Especially in the low-voltage sector, where plastics dominate, knowledge of the most important standards is essential. These standards, which are mainly provided by the International Electrotechnical Committee (IEC), ensure uniform safety and quality requirements worldwide. Here are six crucial standards that everyone in electrical engineering should know:
IEC 60664 – Insulation coordination for low voltage
IEC 60664 is a comprehensive basic safety standard that defines minimum requirements for devices and equipment with rated voltages up to 1000 VAC and 1500 VDC. The key contents include:
Air and creepage distances
The standard defines the minimum distances between conductive parts to prevent electrical breakdowns and leakage currents. These distances are crucial to ensure operational safety and prevent failures due to flashovers.
- Example: When designing printed circuit boards in household appliances such as washing machines, the distances between conductive tracks must be carefully measured to prevent arcing, especially in humid environments.
Correction factors
The standard specifies correction factors for use above 2000 meters above sea level and at higher frequencies. These adjustments are necessary to accommodate the changed environmental conditions and to ensure the safety and performance of the devices.
- Example: In aeronautical engineering, where equipment is often used above 2000 meters, the insulation distances must be adjusted to compensate for the lower air pressure and ensure the same level of safety.
Other aspects
IEC 60664 also covers the selection and testing of insulation materials used in low-voltage installations and ensures that these materials meet the specific requirements of the application.
IEC 62368 – Safety requirements for IT technology
IEC 62368 is a basic safety standard for electrical and electronic equipment in the field of audio, video, information and telecommunications technology up to a nominal voltage of 600 V. This standard includes a comprehensive risk assessment and refers to:
electric security
The standard specifies measures to prevent electric shocks and short circuits. It contains requirements for insulation, earthing and protection against overcurrent and overvoltage.
- Example: When designing computers and servers, power supplies must be designed to protect against overvoltage to avoid damaging sensitive electronic components.
Mechanical risks
IEC 62368 also considers mechanical hazards and ensures that equipment cannot cause injury from moving parts or sharp edges. Mechanical stability and robustness are also key aspects.
- Example: In printers and copiers, moving parts such as rollers and print heads must be designed so that they do not pose a risk of injury to the user.
Acoustic hazards
The standard also covers protection from acoustic hazards, such as hearing damage caused by loudspeakers. It sets limits on volume and sound intensity to protect users.
- Example: In home theater speaker systems, the maximum volume must be limited to avoid hearing damage.
Thermal and chemical risks
In addition, the standard addresses thermal and chemical risks, including overheating of components and the use of hazardous substances.
- Example: When manufacturing tablets and smartphones, care is taken to ensure that the batteries do not overheat and that no dangerous chemicals can leak out.
IEC 61140 – Protection against electric shock
IEC 61140 specifies basic requirements for protection against electric shock for installations, systems and equipment, regardless of voltage. The standard defines the following protection classes:
Protection class I
All conductive housing parts are firmly connected to the protective conductor system of the electrical installation. This ensures that a safe earthing path is available in the event of a fault.
- Example: In electric stoves, all metal housing parts are connected to the protective conductor in order to safely discharge the current in the event of a short circuit and to prevent an electric shock.
Protection class II
Use of double or reinforced insulation without connection to the protective conductor. This class provides additional protection by preventing conductive parts of the enclosure from becoming live in the event of an insulation fault.
- Example: Electric hand tools such as drills use double insulation to ensure that the user is not at risk in the event of an insulation failure.
Protection class III
Operation with extra-low voltage below 48 VAC/60 VDC, supplied by SELV (Safety Extra-Low Voltage) or PELV (Protective Extra-Low Voltage) power sources. This protection class minimizes the risk of electric shock by using safely low voltages.
- Example: Aquarium lighting systems often use protection class III to minimize the risk of electric shock in the humid environment.
Additional aspects
The standard also covers protection against indirect contact and insulation requirements to ensure the safety of users and maintenance personnel.
IEC 60112 – Tracking resistance
Plastics have a higher insulation resistance than air, but their performance can be affected at the interface by moisture and contamination. IEC 60112 determines the "Comparative Tracking Index (CTI)" to evaluate the tracking resistance of plastics:
CTI value
The CTI value is a measure of a material's resistance to electrical degradation in humid and dirty environments. A higher CTI value means better resistance.
- Example: In the automotive industry, plastics with a high CTI value are used to ensure that electronics function reliably even in damp and dirty conditions.
Insulating material groups
The standard classifies materials into different groups based on their CTI value:
- I: CTI > 600 V
- II: 400 V ≤ CTI < 600 V
- IIIa: 250 V ≤ CTI < 400 V
- IIIb: 175 V ≤ CTI < 250 V
- IV: 100 V ≤ CTI < 175 V
This classification helps in selecting suitable materials for different operating conditions.
Applications
Tracking resistance is especially important in environments where moisture and dirt are present, such as industrial or outdoor environments. Selecting a material with the correct CTI value can help minimize electrical faults and failures.
UL 94 – Flammability of plastics (IEC 60695)
UL 94 is a widely used standard for evaluating the flammability of plastics. It classifies materials based on horizontal and vertical burning tests:
Horizontal Burn Test (HB)
- HB 75: For materials with a thickness of less than 3 mm; passed if the burning rate is less than 75 mm/min.
- HB 40: For materials with a thickness of more than 3 mm; passed if the burning rate is less than 40 mm/min.
Vertical burning test (V)
- V-2: Material must extinguish within 30 seconds, flaming droplets are permitted.
- V-1: Like V-2, but without burning droplets and no afterglow over 60 seconds.
- V-0: Material must extinguish within 10 seconds, no afterglow for more than 30 seconds.
- 5VB: At least V-2 achieved, additional five flame treatments with 500 W flame, no dripping permitted.
- 5VA: As for 5VB, but no burn hole formation larger than 1 mm in a horizontally clamped plate.
Additional tests
For thinner materials, there are modified test arrangements that ensure that these materials also meet the fire protection requirements.
- Example: The manufacture of electrical equipment such as televisions and computer monitors requires plastics that must meet at least class V-0 to ensure that no dangerous flames or flaming droplets occur in the event of a fire.
IEC 60085 – Thermal classes (similar to UL 746)
IEC 60085 classifies electrical insulation materials and systems according to their thermal resistance. The thermal classes range from Y (95 °C) to R (220 °C) and help in selecting suitable materials for different temperature conditions:
Heat classes
- Y: 95 ° C
- A: 105 ° C
- E: 120 ° C
- B: 130 ° C
- F: 155 ° C
- H: 180 ° C
- N: 200 ° C
- R: 220 ° C
application scenarios
Selecting the correct thermal class is crucial to ensure that insulation materials are not damaged by overheating and lose their insulating properties.
- Example: In the electric motor industry, materials of thermal class H (180 °C) are used to ensure that the insulation remains stable and does not fail even at high operating temperatures.
Knowledge and application of these six standards is essential for the safety and reliability of electrical engineering projects. At Dr. Dietrich Müller GmbH we offer a wide range of insulation materials that comply with these and other international standards. Our products, including highly thermally conductive materials such as Thermigrease TG 20032, are specially developed to meet the highest requirements.
Examples from our range
- Thermigrease TG 20032: A highly thermally conductive material, ideal for applications that require efficient heat dissipation, such as power electronics.
- Double-sided adhesive tapes: Used for secure fastening and insulation in electronic devices, providing excellent adhesion and electrical insulation.
- Flexible insulating films: Perfect for insulation in tight spaces and applications that require flexibility and high insulation values.
Our experts are always available to help you choose the right materials for your specific needs. Visit our website or contact us directly to learn more about our products and services. Together we can shape the future of electrical engineering safely and reliably.
