emc safety

Intertek Testing Services 70 Codman Hill Road, Boxborough, MA

www.intertek-etlsemko.com

Insider’s Guide to Faster Safety & EMC Testing

Introduction

Bringing a new product to market is a complex and involved process that requires the talent and expertise of a wide range of personnel within an organization; business strategists, product designers and engineers, production teams and line staff to name a few. Amidst the flurry of development activity within these teams, Safety and EMC product compliance issues may seem to be a low priority – at very least until a prototype is built. Indeed how can you test something for compliance when it doesn’t actually exist? By postponing compliance considerations until later in the development cycle, it can cause delays in launching a product to market. Testing can reveal non-conformities that require a product redesign or modification then retest – lengthening the compliance process significantly. Indeed it is common that modifications made to a product for EMC compliance can effect safety compliance. For example, having to add extra insulation into a product can reduce the current creepage and clearance distances required for safety purposes, potentially making it unsafe. Similarly, changing bypass capacitors to comply with safety leakage current requirements can throw off EMC compliance. The product then has to be modified to fix this problem and then retested for safety. With such a potentially complex situation, it seems obvious that product safety and EMC compliance should be considered from the earliest concept stages of development (and in an integrated way) to keep launch disruption to a minimum. Product modification and retest delays can have a critical impact on your business, potentially costing you thousands in lost revenue (missing out on Holiday sales for example) as well as damage to your brand. Your competitors could get their rival products to market first, making them - in a consumers mind at least - a “leader” and everyone else that comes after a “follower”. In this document, we will explore some simple, practical strategies that ensure these compliance considerations can be addressed early, and enable the compliance process itself to be optimized to help reduce time to market, costs, chances of delay and the likelihood of having to make frustrating modifications and retests to your product.

Knowledge is Power

It is a cliché to say knowledge is power, yet despite that, it is true. When a company decides to expand its portfolio of products, the first thing done is market research. Is the product needed/wanted in the marketplace? What are the competitive products, and what are their weaknesses? What features would make the new product better than anything else available? What would its life be? Would it need to be repairable/upgradeable? Does it have to be functional or aesthetic or both? How much should it cost? And most importantly, to whom is this product targeted and in which countries can it be sold?

These last two items of information are essential knowledge for the development team, so try and get a copy of the market research for the proposed product. Depending on the depth of the research, this will give some indication as to any special Safety or EMC conditions that may have to be considered during the design (e.g. Is this product for home or commercial use; is it aimed at able-bodied users? Or children or the elderly?) and it will also show which regional regulations will have to be met.

This knowledge is key to organizing the compliance schedule and budget itself as you can use the existing knowledge of your engineers to identify the probable Safety and EMC test plan and likely costs – based on previous projects. For example, in the US, domestic products must be tested for EMC emissions, not immunity. In Europe, domestic products must be tested for both. If your product is going to Europe, your test plan for compliance in this region is therefore likely to take a little longer, cost a little more and will probably require more samples and spares to be provided to the test house. These factors can then be built into your compliance plans, helping you to anticipate the requests of the test house, saving you time when you actually come to the testing stage.

Standards & Local Deviations Knowing the safety and EMC regulations for a new product in the target market is essential for the product development team. This enables them to obtain appropriate Standards for those markets (indeed they can select Standards that give them maximum geographical coverage) and design the product with the safety and EMC requirements of these Standards in mind. Standards & Jurisdiction US - FCC/ FDA US/EU - FCC, IEC, CENELEC Asia Pacific - FCC or IEC with deviations Product Jurisdiction Standard ITE USA FCC Part 15, 60950-1 ITE EU, Asia CISPR 22/EN 55022, CISPR 24/EN 55024 Medical USA, International IEC 60601-1-2 Test/Measurement 61010-1 Audio/Visual 60065 Household Appliances 60335-1 Electrical Tools 60745-1 ISM USA FCC Part 18 ISM EU, Asia EN 55011 +… Lab USA Exempt Lab EU EN61326-x Radio USA FCC Part 15, 22, 24, 25, 27, 74, 90, 95 Radio EU ETSI EN, EN 301 489 -x

Insider’s Guide to Faster

Safety & EMC Testing

Purposefully designing a product for safety and EMC conformity seems a cautious and conservative approach to product design that restricts creativity and innovation, but it is likely to reduce your chances of product failure at the testing stage. A Note on Standards Use

Many companies maintain an in-house library of Standards that relate to their product ranges with a view to ongoing safety and EMC compliance within their target markets. These libraries can be extremely effective in aiding designers, but two issues need to be highlighted. The first is the matter of interpretation. Some of the language used in Standards – particularly in

those sections relating to specific tests to be conducted, can be interpreted in a number of ways. Calling upon the expertise of a testing and certification partner to interpret the fine detail of a Standard can help designers and engineers overcome the hazards of ambiguity and potential product non-conformity. If the issue has particular subtleties, your test partner can even approach the Standards Developing Organisation (SDO) directly for a definitive explanation. The second issue with in-house Standards libraries, is the need to maintain the latest version of the Standard. When potentially dozens of Standards need to be maintained, it is possible that an expiring document may be overlooked. Here auditors and quality managers play their part in keeping the available documents up to date – but again your testing and certification body can provide you with the latest (and upcoming) Standards updates and information on local safety and or EMC deviations that might apply to a sub-section of your target market. Standards are expensive! But on the other hand, how expensive is it to re-work a non-compliant product design, or, how expensive is it to miss a product launch date in the market place? Purchase of the standard is a good investment and is quite inexpensive when compared to the cost of re-submittal to the test lab.



Understanding Dates of Withdrawal (DOW) and Standard Version terminology Ensuring that you’re using the appropriate standard is an obvious thing, but understanding the validity of dates within those standards is critical to using the right one! It would be incredibly frustrating to commission product tests against a Standard in your library and then find that it is soon to expire and that any testing and certification will need to be revisited. The new version of the Standard my not require any additional tests to be completed – it could be a something as simple as a new labelling requirement, but it could require product modifications and a re-test. Understanding how the dating information in Standards works could save you time and expense in having to revisit your test program soon after completion because the Standard that was tested against is no longer the newest version. Outlined below are some brief explanations of critical Standard dates and terminology for standards in the EU: Approved Draft The Approved Draft Date is usually found in the Foreword at the front of the Standard. This date is essentially when the Standard text was “Approved” by CENELEC, prior to publication by the National Standards Bodies. DOP - Date of Publication The DOP or Date of Publication is the date by which the Standard must be published by all countries’ National Standards Bodies. The DOP is usually 6-12 months after the document has been “Approved” by (for example) CENELEC and once the document is published, it becomes the current version of the Standard. Amendment Dates As you would expect, Amendments to Standards (also found in the foreword and designated with the letter A and numbered in sequence e.g. A1, A2 etc) also have an Approved Draft Date and a DOP, but in European Standards, you will also find a Date of Withdrawal (DOW). This DOW indicates the date when the Standard it is associated with can no longer be used on its own - i.e. without the new Amendment. DOWs are also found on fully re-issued Standards. It doesn’t indicate that the Standard as a whole will cease to be current on that date.



Amendment Numbers An interesting point to note is that Amendments are numbered in a specific way. Generally speaking a single number after an A, e.g. A1, A2, A3 etc indicates that an amendment applies to both IEC and EN versions of the Standards. However, if an amendment only applies to the European Standards - say in order to comply with a piece of European legislation then a two digit number will be used, e.g. A11, A12, A13 etc. Essentially if

you have an A1 amendment and an A11 amendment in the same document - you haven’t missed amendments 2,3,4,5,6,7,8,9 & 10! - It’s just that there are two different amendments to that Standard; one for International use, one for European. BS, EN & IEC The name of a Standard will be designated with a BS, EN or an IEC. A BS designation indicates a British Standard, an EN designation indicates that it is a European Standard and an “IEC” designation indicates a worldwide Standard. Part 1s and Part 2s Many Standards will be divided into part 1s and part 2s. Part one usually refers to a generic category of products - for example “Household and similar electrical Appliances” and gives details of general requirements for them and part two refers to specific items in that category, say for example room heaters. REMEMBER! For certification purposes, a product can only be said to conform to a Standard that is still current. For example if I test a product to a particular Standard and then an amendment is published for it, my product will not comply with the most current (now amended) version of the Standard once the Date of Withdrawal on that Amendment is passed. Similarly, if you have a Certification for a product that doesn’t expire for several years - but the Standard that was used to get that Certification gets Amended before your certification runs out, you must contact your Certification Body to enable them to determine what you need to do to comply with the latest version



of the Standard. Sometimes you may need to do additional testing - sometimes the conformity is purely a documentary exercise but you must ensure that your product meets the most current version of the Standard. The Devil is in the Details: Designing for Compliance Continue to use the knowledge and expertise of your product designers and engineers to “design for compliance”, but also use the available product Standards as design reference tools and even look at existing best of breed products to see how they have overcome certain design challenges. By establishing safety and EMC compliance as a fundamental design goal, along with functionality, ease of use, aesthetics etc at the start of the design process, compliance issues can be tackled earlier in the design cycle. Compliance will be seen as a production imperative not a last minute addition to the project. This will reduce chances of product failure at the test phase as the product itself will be “designed for compliance”. Issues to consider during the design phase:

• Materials – knowing the characteristics of the materials that could be used in the product and how they behave in certain environments can help you choose materials that make optimum contribution to safety and EMC compliance

• Printed Circuit Boards (PCBs) – Consider the architecture and positioning

of PCBs for optimum protection

• Ventilation – Keeping a product cool is important but will the venting enable EM radiation to seep out at unacceptable levels? Or bring instability to the system?

• Shielding – by adding shielding to prevent EMC emissions, are you

reducing the clearance of electrical components within the system? Will the extra material enable the system to overheat?

• Family resemblance – Perhaps minimize the differences within suites of

products if you want to minimize the testing they have to undergo. The



fewer the differences between them the less complicated (and costly) the testing will be.

• Cabling – does the cabling have optimum shielding and protection?

• Software and virtual testing – some immunity upsets can be corrected or

mitigated by suitable operating software/firmware design. Also, consider the use of virtual testing software. A number of IT packages are available that can model and analyse a product design that can help designers design for compliance.

Choosing Components Where possible use listed or certified components in critical systems in the product. e.g., controls, transformers, components in the 120 or 240 primary circuit, etc (and know their ratings and conditions of use) as these will contribute to the overall compliance of your product. Also with some specific products – like UK plugs for example, having certified sub-systems like pre-approved moulded pin inserts means that some of your testing has already been done and you could save money on your overall test program.

The temptation to use non-listed components because they are cheaper can be a false economy – they are likely to be unproven, and unless the manufacturer is reputable or at least already trusted by you, they could be of questionable quality. In addition, such non-listed components may require extensive additional evaluation and testing, including annual re-testing. Just remember if a batch of

components (and even materials) seems a bargain that is too good to be true, it probably is. A Note on Modifying Established Products If you are redesigning or modifying an existing product, even if you are simply swapping one component for another from a different supplier, don’t forget to tell your testing and Certification/Approval partner, so they can determine if any additional testing is required. Swapping one component for another may have implications that weren’t anticipated when the substitution was made and if you don’t notify your partner; it may invalidate your certification. Very often



substitutions have no impact on a product at all, and no further testing is needed, but it is important that documentation is updated with the change for auditing purposes. Putting Pen to Paper Documenting the design and production process is invaluable for the compliance process. Quality Management tools and Project Management systems provide a useful structure for capturing information that not only can it help an engineer re-trace their steps and identify a problem if a product shows a non-conformity during the testing process, but it will also help them to keep track of components and schematics for easy reference – particularly if they are creating a suite of products. The testing and certification team at your partner laboratory will require access to the component and materials lists as well as circuit diagrams and drawings in order to be able to test and assess the product. Surprisingly, a great many testing and approval projects get delayed, not because of the modification of product or because a failure of tests, but because the test lab hasn’t had all of the paperwork they need to move a project forward. It seems bureaucratic, but as test houses and certifying bodies are regularly audited to ensure the work they do is to a consistent and of high standard, they need to have all of the relevant documentation necessary to conduct the work. Sometimes the most simple of required “paperwork” (user manual, installation instructions, product markings, etc.) is not provided. If a manufacturer can have all of the relevant documentation ready for the test house, frustrating delays can be avoided. In your records, it is also beneficial to keep a list of contact names and numbers and email addresses for the team at the test lab, and some calendar notes to check in regularly with them to check on the project progress. Some



manufacturers don’t do this as they want no part of the compliance process, but many others have found an active dialogue with the test house and an understanding of and proactive involvement in the process can help reduce the time it takes and reduces the number of potential issues that could arise. Design Review Many manufacturers have found it beneficial to have a design review conducted by their test or certification partner. This highlights any design issues early and can be conducted using the circuit diagrams, component lists, design drawings – and if it is available, a prototype. Initial discussions with the certification partner can even begin with an artists rendering or cardboard mock-up. If necessary the product can then be modified or re-worked before ever reaches the laboratory. Your partner will not only review the product but they can also be used as a source of reference for interpreting Standards. The Compliance Process

Understanding the Safety and EMC and compliance process and actively preparing for and participating in it can help reduce the time it takes to complete it successfully. It is tempting to hand a product over to a test house, and take a “hands off approach” to compliance. Obviously your laboratory partner has both the expertise and the facilities to test a product to Standard and is fully capable of managing the process. However knowing the type of tests your product will undergo and where possible conducting

some preliminary testing yourself, can help give you some initial feedback on where your product might fail, enabling you to make appropriate modifications before a product reaches the formal testing stage.



What can a man with a radio do? The most basic of all EMC tests – that you can conduct yourself without specialist equipment or test chambers - is the radio test. Switch on your radio and hold it near your live appliance and see if the reception becomes distorted. If it does, it’s likely that your product needs better emissions mitigation. Other basic bench tests can usually be conducted at site with some help from your test laboratory team. They can give you direction on equipment you will need, guidance on specific tests and even observe some testing so it can be included in the formal compliance assessment. Keep it in the Family When you are submitting products to the laboratory for testing, group them into a family of products, and submit as many similar items as is feasible at the same time. This will help to reduce the cost and time required for the compliance process for multiple items. If that isn’t possible then try and arrange a worst case (fully loaded) configuration that can represent the other units in the family. Partners

Choosing to work collaboratively with a compliance partner like a test house or a certification body from the beginning of the design process can also bring clarity and speed. Particularly if a manufacturer’s design team has a thorough understanding of the compliance process and can prepare in advance for the requests of test house. As well a providing advice on what Standards should be referenced during the design phase and how to interpret them; they can also conduct design review and give general guidance throughout the

development of where issues typically lay. This will help manufacturers to prepare their product for test and reduce the likelihood of failure.



Conclusion In a global market where the ability to innovate and respond to market needs with new and vibrant products is the mark of world leading brands, time to market is a key factor in determining both the success of a particular product and ultimately the ongoing commercial success of a company. As each trading area in the world has its own set of specific regulations and requirements for these products, minimizing the time to meet these is critical to reducing time to market. To reduce the time it takes to complete the compliance process the manufacturer can:

• Consider compliance issues from the beginning of the design process. These need to be an integral part of the creation of a new product, not an afterthought.

• Use the knowledge and expertise available to them to ensure they are designing product to the latest versions of the Standard, and that they have taken into consideration the local deviations that may apply to their product. A test partner will be able to advise on what Standards to use, and if required, how to interpret them.

• Improve their understanding of, and increase their involvement in the compliance process. By anticipating the needs of the test house, response and delivery times can be improved.

• Design for compliance. Deliberately use appropriate materials, proven designs and approved components that provide adequate EMC shielding and reduce hazards from electrical shock.

• Maintain a detailed technical file on the project – so when the test house makes a documentation request, everything required is quickly available.

• Utilize a design review from their partner test house to ensure that they are on the right track and that any issues can be spotted and rectified early in the product development process.

There is no magic solution to prevent all of delays with EMC and Safety testing. Sometimes products fail and sometimes delays occur for other reasons, but with these simple, common sense efforts, they can at least be reduced. Designing for compliance is an unromantic notion, but a common sense one. You can optimize the testing process with proactive involvement, but a well designed product that meets all of the criteria required of it, will be the most influential factor in getting through the compliance process, fast.



About the Authors Roland Gubisch is the Chief Engineer, EMC and Telecom, Intertek Testing Services. In this capacity he is responsible for the technical activities in EMC and telecommunications testing of Intertek laboratories in the US and Canada. He has been with Intertek for 17 years. He is also the Certification Body Manager at Intertek for FCC and Industry Canada radio certification activities.

His industry activities include the IEEE Working Group for Power Line Communications EMC standards, membership in the Administrative Council for Terminal Attachments (ACTA), and TIA liaison groups with the FCC for wireless communications. He holds domestic and international patents in the fields of optical and chemical instrumentation, and network test apparatus. He is a member of the IEEE, and IEEE Communications and EMC Societies. Jim Pierce is the Chief Electrical Engineer for Intertek Testing Services. He began his career with UL over 30 years ago as an Engineering Technician and moved up in the organization to managing 40 engineering staff. He joined Intertek in 1990 and held various engineering management positions over the years. His responsibilities include: preparing and conducting training programs for Intertek’s technical staff and monthly worldwide training webinars and annual requalification of Reviewers Webinar sessions. Mr. Pierce is a member of the National Fire Protection Association (NFPA) and is currently serving on National Electrical Code (NFPA 70) Panel #18 and is also a member of the NFPA 79 Technical Committee (Industrial Machines). He also serves on many ANSI, NEMA, NFPA and UL Standards Maintenance Review Boards. In addition, he has been an Inspector member of the International Association of Electrical Inspectors (IAEI) and has served on their monthly Code Panel Forums, for over 17 years. Natasha Moore is a technical author and editor specializing in electrical safety and certification information. Based at Intertek UK, she was the contributing editor of ASTA BEAB’s Update magazine and recently wrote the Intertek whitepaper “The Engineers Guide to Solving World Problems: 5 Strategies for Efficient Global Market Access.”

For more information on specific testing and certification information, please contact Intertek at 1-800-WORLDLAB, email [email protected], or visit our website at www.intertek-etlsemko.com.

This publication is copyright © Intertek and may not be reproduced or transmitted in any form in whole or in part without the prior written permission of Intertek. While due care has been taken during the preparation of this document, Intertek cannot be held responsible for the accuracy of the information herein or for any consequence arising from it. Clients are encouraged to seek Intertek’s current advice on their specific needs before acting upon any of the content.

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