Why Mass Production Fails EMC Tests
Why Mass-Produced Equipment Fail EMC Tests
Electromagnetic compatibility (EMC) tests are a critical step in designing electrical and electronic products. Recently, EMC tests have become a matter of concern due to the global increase in production of all types of E&E equipment.
The number of E&E products that have become a part of our daily lives has been steadily rising over the past 25 years. This has resulted in an increase in electromagnetic waves in the atmosphere that in turn led to authorities setting stricter EMC limits.
Type Approval is not Enough
The responsibilities of both authorities and manufacturers have become increasingly complex. Authorities have to verify the countless products being placed on the market while manufacturers need to make sure that all their equipment from every product category meets applicable EMC requirements.
Under such conditions, simple type approval turns out to be insufficient when producing E&E equipment that meet applicable EMC limits. There are many reasons that cause mass-produced models to fail EMC tests, but have type approval from EMC labs. Sometimes the fault lies with the specifications of the components used, the wiring and modifications during production, etc.
Passing EMC Testing Requirements
To ensure that all products pass the relevant EMC tests, manufacturers and third party companies can implement, according to CISRP 13/22, either of the following solutions:
- “Safe Margin” – Involves reducing EMC limits to stricter levels, based on the type of equipment and the risks of EMC test fails during type approval. EMC limits may be reduced by 5/6 dB and this method seems to be helpful for manufacturers who don’t have EMC labs. However, this method may not work in all cases, especially when manufacturers have multiple products in the same product category.
- “Statistical Method” – Involves testing product samples during mass production. Statistically assessed compliance with limits requires that tests be performed on a sample of 5 to 12 products of one type. In exceptional situations, where five samples are not available, a sample of 3 or 4 may be enough. Success through this method requires, on a statistical base, that 80% of the mass produced equipment comply with the limits with at least 80% confidence.*
* Information taken from CIRSP22SGS runs the largest EMC testing and certification networks in the world, with EMC testing facilities strategically located in proximity to manufacturing centers in the largest E&E markets in the world.
For more information on EMC Solutions by SGS, please contact:
EMC and Safety Test Engineer
t: +90 212 3684000/329
The SGS Group is the global leader and innovator in inspection, verification, testing and certification services. Founded in 1878, SGS is recognized as the global benchmark in quality and integrity. With more than 56,000 employees, SGS operates a network of over 1,000 offices and laboratories around the world.