EMC Pre-compliance Testing

What is EMC pre-compliance testing?

Electromagnetic compatibility (EMC) testing is a vital step in your product's development plan. EMC pre-compliance testing works to identify potential problems early in your design process, before full-scale testing takes place. This gives you an incremental, stage-by-stage portrait of your product and its potential EMC-related design flaws, helping you avoid inconvenient product redesigns that can result when testing is put off until the final phase of the design plan.

Avoid failing full-scale EMC compliance testing

Here’s the key reason for pre-compliance testing: EMC testing outcomes are usually specific to a product’s design, meaning that EMC technicalities particular to a design plan can stop a product from passing. Our EMC experts find that it’s not unusual for new products to fail initial full-scale compliance testing, which is why we offer EMC pre-compliance to help catch problems before full-scale testing is conducted. 

Why some designers put off EMC testing

Due to stringent EMC regulatory requirements, some product designers may assume that EMC testing is a routine, one-size-fits-all process—that one designer’s product tests the same way as any other. Because of this, it’s not uncommon for designers to put off compliance testing until the end of the design cycle, which can lead to complications in compliance such as delayed launch dates, irritated customers and/or distributors, disrupted design plans and additional fees to address the problem. EMC pre-compliance testing can help to avoid these unnecessary hiccups. 

How EMC pre-compliance testing can save you money 

EMC pre-compliance can help you steer clear of unanticipated spending by demonstrating where potential EMC issues might arise, giving both insight and time for efficiently planning your design steps. While it doesn’t’ test to full certification, pre-compliance can help identify potential hang-ups early in the process to help you avoid the cost of repeating full-scale testing. Other benefits may include:

• Testing at an accredited EMC laboratory can help reduce testing time when applying for full certification.
• Pre-compliance testing for both radiated and conducted emissions can help you identify likely sources of failure during early design phases.
• Immunity test results subject the device to different types of immunity disturbances to find design weak spots.

Common technical causes of initial EMC test failures

Knowing common reasons that products fail EMC compliance can help you anticipate potential postponements, as well as keep you in the loop during the pre-compliance process: 

• Lack of knowledge of EMC principles 
• Failure to apply EMC principles 
• Application of incorrect EMC regulations 
• Unpredicted interactions among circuit elements
• Incorporation of noncompliant modules of subassemblies into the final product 
• Uncontrolled environment conditions like relative humidity, temperature and altitude producing different test results
• Testing power supplies separately from full product 
• Not considering conducted radio frequency (RF) from cables at low frequencies or radiated RF at high frequencies

Key design considerations to increase the chance of passing EMC tests 

Stay updated with strategies and troubleshooting that can help your product effectively move through both EMC pre-compliance and full-scale compliance testing. Increase the likelihood that your product meets compliance by familiarizing yourself with some of the common causes of initial EMC test failures, including: 

• Components tolerances/limitation
• Logic families
• Printed circuit board (PCB) and input/output (I/O) layout
• Cable selection and, more importantly, the routing path within the product enclosure
• Enclosure and shielding  
• Software and firmware 
• Power supply module/circuitry selection

Why UL Solutions for EMC pre-compliance testing

We understand that EMC testing can be daunting. Our EMC pre-compliance service was designed to help you identify potential EMC issues as effectively and efficiently as possible. Leverage our EMC pre-compliance expertise early in your development process. Avoid costly errors in design and accelerate time to market.