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EMC Explained Pt.1: What do all the symbols mean? Over the last few years there has been a lot of concern over the introduction of stringent new EMC requirements that all electronic and electrical products must meet. In this short series, we will discuss the new regulations, how they came about and how they apply in Australia and New Zealand. By MARQUE CROZMAN Actually, it is a pretty dry old subject but it is crucial to Australian industry and ultimately to consumers so it deserves a thorough examination. But first, what do all the symbols mean? The most common symbol is “CE” and indicates that the equipment conforms to European standards. In fact, an electrical or electronic product cannot be sold in Europe unless it bears the CE marking. European countries have settled upon a set of uniform or “harmonised” standards. In May 1985, European Community Ministers agreed on a ‘New Approach to Technical Harmonisation and Stan­dards’ in order to remove trade barriers based on techni- cal grounds. This was to eliminate the need for separate product certification in each country. ‘New Approach’ Directives broadly set out the essential requirements which must be met before products could be sold in Europe. The standards which fill in the technical details were then provided by the IEC (International Electrotechnical Commis­sion). The IEC is made up of the standards bodies of 49 countries including all the EU and EFTA. Other bodies that have provided standards are CISPR (Comite’ International Special des Perturba­tion Radioelectriques - International Special Committee on Radio Interference) and CENELEC (Comite’ European de Table 1: Generic Standards Applicable To Electronic Equipment Emissions EN50081 Part 1 Part 2 Electromagnetic compatibility generic emission standard Residential, commercial and light industry Industrial Susceptibility EN50082 Part 1 Part 2 Electromagnetic compatibility generic immunity standard Residential, commercial and light industry Industrial 16  Silicon Chip Normatination Electro-technique) – a group set up to work out the nuts and bolts of creating common European equipment standards. What does CE mean? CE stands for “Conformit Europe­ ane” and is a set of EC Directives that are backed by standards that relate to electro­magnetic compatibility. The CE label can only be used on a pro­duct if the manufacturer can demonstrate that the product com­plies with the essential requirements of the EMC Directive (and all other applicable EC Directives). The directives most relevant to electronic products are ‘The EMC Directive’ (CE), ‘The Low Voltage Directive’ (LVD), and ‘The Machinery Directive’ (MD). The EMC Directive The European Commission’s Electromagnetic Compliance Direc­ tive 89/336/EEC relates to the electromagnetic emissions and susceptibility of electronic products. It came into full effect at the beginning of 1996. It requires that apparatus not generate excessive electromagnetic disturbance levels that would interfere with the proper functioning of other devices or radio and tele­ c ommunications equipment. Secondly, the apparatus must provide a level of immunity to electromagnetic disturbances to enable it to operate as intended. The specific levels are determined by a set of standards produced as a result of the directive. Turning that legalese into English, the standards are divided into two sections. The first covers emissions and the second, susceptibility. Emissions refer to electromagnetic radia­ tion produced by the device. relate to spe­cific tests and methods of testing. Table 2: Commonly Found Product Groups Emissions Standard EN55011 EN55013 EN55014 EN55015 EN55019 EN55022 Equipment covered Industrial, Scientific and Medical (ISM) equipment Sound and TV broadcast receivers and associated equipment Household electrical appliances, portable tools, etc Fluorescent lamps and luminaires Microwave ovens Information Technology Equipment (ITE) Immunity Standard EN55020 Equipment covered Sound and TV broadcast receivers and associated equipment For example, your hair dryer emits radiation which causes the interference to your TV set. Susceptibility refers to the amount of radiation present in the environment that the device has to withstand before its normal operation is affected. For example, some computers do odd things or crash when mobile phones are operated near them – the mobile phone produces a higher level of electromagnetic interfer­ence than the PC can withstand and it performs oddly. The standards are based on a hierarchical model, starting with generic standards that apply to all products. From there, the standards become more specific to product groups, then pro­duct families and finally, to specific products. The generic standards are the toughest to pass, with the more specific stan­dards making allowances for particular devices. The standard that best fits the product description Compliance tests If a product has either or both of these marks stamped on it, it complies with current EMC emissions standards in Australia. is the one that is used. Thus products that do not have individual standards or family stan­dards must use the generic standard – see Table 1. For products where no standard can be applied, another compliance method can be used. This is called the Technical Construction File (TCF) route to compliance. The generic and product standards specify emission and immunity levels and call up other standards that Fully Accredited Testing for Tests carried out to ensure EMC compliance include: •  conducted electromagnetic emissions. •  radiated electromagnetic emissions. •  immunity to electrostatic discharge (static electricity). •  immunity to electrically fast transients (such as switching transients). •  immunity to conducted RF (such as mains-borne interference). •  immunity to radiated RF (local RF fields). Other tests are carried out depending on the equipment might include susceptibility to mains harmonics, surges, voltage dips and interruptions. Levels and methods of testing are deter­mined by the standard being applied. Equipment that is exempt from the EMC directive: •  Equipment for export only. •  Spare parts. •  Secondhand equipment. •   Electrically benign apparatus (power consumption less than 6 nanowatts). •  Equipment for use in screened rooms. •  Amateur radio equipment. •  Military equipment. •  Active implantable medical devices. •  Educational electronic equipment designed for the study of electromagnetic phenomena. Global Markets EMC Technologies' Internationally recognised Electromagnetic Compatibility (EMC) test facilities are fully accredited for emissions, immunity and safety standards. >> NATA endorsed reports for ALL electrical products covered by the and regulations >> Accredited Competent Body for TCF approval >> Anechoic chamber for accredited immunity testing. Field uniformity ensures that your products are not "over tested". DC – 1000MHz <at> 100-200V/m, 1-18GHz & >50-100V/m >> Open Area Test Site (OATS) available for hire for DIY testing >> Low ambient OATS in Melbourne, Sydney and Auckland (NZ) >> RF testing DC – 40GHz >> CE (Europe), FCC (USE), VCCI (Japan) EMC Technologies Melbourne T: +61 3 9335 3333 F: +61 3 9338 9260 E: melb<at>emctech.com.au Sydney T: +61 2 9899 4599 F: +61 2 9899 4019 E: syd<at>emctech.com.au Auckland T: +64 9 360 0862 F: +64 9 360 0861 E: auklab<at>emctech.com.au Visit our website: www.emctech.com.au August 1998  17 MORE FROM YOUR EFI CAR! Own an EFI car? Want to get the best from it? You’ll find all you need to know in this publication EFI TECH SPECIAL Here it is: a valuable collection of the best EFI features from ZOOM magazine, with all the tricks of the trade – and tricks the trade doesn’t know! Plus loads of do-it-yourself information to save you real $$$$ as well . . . HERE ARE JUST SOME OF THE CONTENTS . . . n Making Your EFI Car Go Harder n Building A Mixture Meter n D-I-Y Head Jobs n Fault Finding EFI Systems n $70 Boost Control For 23% More Grunt n All About Engine Management n Modifying Engine Management Systems n Water/Air Intercooling n How To Use A Multimeter n Wiring An Engine Transplant n And Much More including some Awesome Engines! AVAILABLE DIRECT FROM SILICON CHIP PUBLICATIONS PO BOX 139, COLLAROY NSW 2097 - $8.95 Inc GST & P&P To order your copy, call (02) 9979 5644 9-5 Mon-Fri with your credit card details! FROM THE PUBLISHERS OF “SILICON CHIP” Table 3 EMI SHIELDING PRODUCTS Class of Equipment Type of Protection Class I Electric shock protection is achieved by (a) basic insulation and (b) protective earth All conductive parts which could assume hazardous voltages in the event of failure of basic insulation must be connected to a valid protective earth conductor. Class II Electric shock protection is achieved by double or reinforced insulation – no provision is made for a protective earth. Class III Electric shock protection is achieved by relying upon the limited current and voltage of a Safety Extra Low Voltage (SELV) supply – and it is impossible for hazardous voltages to be generated within the equipment. Table 4: Safety Classes Of Equipment Class 1 Electric shock protection is achieved by (a) basic insulation and (b) protective earthing. All conductive parts which could assume hazardous voltages in the event of failure of basic insulation must be connected to a valid protective earth conductor. Class II Electric shock protection is achieved by double or reinforced insulation – no provision is made for a protective earth. Class III Electric shock protection is achieved by relying upon the limited current and voltage of a Safety Extra Low Voltage (SELV) supply - and it is impossible for hazardous voltages to be generated within the equipment. Class III equipment does not need approval as it relies on its SELV (Safety Extra Low Voltage) power supply for protection. Plugpacks are good examples of SELV power supplies. This means that a manufacturer can export equipment without certification, by using a locally approved SELV power supply. •  Test equipment designed to gener- ate or be susceptible to EMI. •  Equipment under maintenance. •  Inputs to other devices (passive components or modules sold exclusively as OEM modules to a sole manufacturer). •  Installations unlikely to generate interference. •  Radiocommunications equipment. C-Tick marking in Australia Australia and New Zealand have adopted an EMC Framework, with harmonised standards linked to European standards. In the first stage, legislation has been passed to phase in the emis­sions part of the EMC directive. New products have needed to comply from the beginning of 1997 and existing manufactured products will be caught from the start of 1999. Products that comply with the Australian/New Zealand direc­ tive are marked with the C-Tick symbol. As our standards are traceable back to IEC standards (with amendments for local condi­tions), testing and certification is carried out in the same way as for CE approvals. Thus the cost of testing for C-Tick is incorporated into CE testing, if the product is for the European market. From the beginning of 1999, electronic products will only be able to be sold in Australia and New Zealand if they carry the C-Tick mark. If a product already has CE approval, C-Tick approval can be obtained by making a submission referencing the AS/NZS equiv­alent of the IEC standards that the product conforms to. The Australian Communications Authority has published a brochure that explains the certification procedure. The Low Voltage Directive (LVD) This safety directive encompasses FROM UK Metal wire gaskets Soft shield gaskets Oriented wire in silicones D Connector gaskets Copper beryllium fingers Board level shielding Carbon & glass tissues Nickel coated carbon tissues FROM BELGIUM Stainless steel fibres for conductor plastics FROM USA Ferrites Microwave absorbers Microwave reflectometers Nickel powders - EMI Paints Zippertubing - EMI Sheaths ITO Films Conductive silicone extrusions FROM GERMANY Suits for EMR Protection SPECIALISED CONDUCTIVES PTY LTD Tel: 61-3-9846 1490 Fax: 61-3-9846 5542 email tetazjr<at>ozemail.com.au (with minor exceptions) all equipment operating from 50V to 1000VAC and from 75V to 1500VDC. It deals with the safety aspects of equipment - protec­ tion against electric shock, flammability, mechanical, radiation and chemical hazards. There are three classes of equipment as defined in Table 4. Tests carried out to ensure compliance include: •  Protection against accessibility to live parts. •  Power input and current. •  Heating. •   Leakage current and electric strength at operating temperature. •  Moisture resistance. •  Overload protection of transformers and associated circuits. •  Endurance. •  Abnormal operation. •  Stability and mechanical hazards •  Provision for earthing. •  Creepage distances, clearances and distances through insulation. •  Resistance to heat, fire and tracking. Other tests are carried out depending on the equipment. SELV power August 1998  19 Silicon Chip Binders REAL VALUE AT $12.95 PL US P&P These binders will protect your copies of S ILICON CHIP. They feature heavy-board covers & are made from a dis­ tinctive 2-tone green vinyl. They hold up to 14 issues & will look great on your bookshelf.   Hold up to 14 issues   80mm internal width  SILICON CHIP logo printed in gold-coloured lettering on spine & cover Price: $A12.95 plus $A5 p&p. Available only in Australia. Silicon Chip Publications PO Box 139 Collaroy Beach 2097 Or fax (02) 9979 6503; or ring (02) 9979 5644 & quote your credit card number. Use this handy form Enclosed is my cheque/money order for Table 5: Examples Of Safety Standards Safety Standard Equipment covered EN60335 Safety of household and similar electrical appliances EN61010 Safety requirements for electrical equipment for measurement, control, and laboratory use EN60536 Classification of electrical and electronic equipment with regard to protection against electric shock EN60601 Medical electrical equipment – general requirements for safety EN61293 Marking of electrical equipment with ratings related to electrical supply – safety requirements EN60730 Automatic electrical controls for household and similar use EN60065 Safety requirements for mains operated electronic and related apparatus for household and similar general use EN60950 Safety of information technology equipment EN60742 Isolating transformers and safety isolating transformers – requirements EN61558 Safety of power transformers, power supply units and similar supplies are interesting on their own, as they are usually covered in symbols. Although Australia and New Zealand have different require­ments for safety, they have harmonised their standards for elec­ trical safety and adopted the use of the Regulatory Compliance Mark (RCD) in a similar role to the LVD in Europe. It requires that certain products, determined to be “Prescribed articles” must carry the mark. Non-prescribed products are also able to carry the mark, as an indication of high standards of electrical safety. Table 6 outlines some of the common products that are deemed as Prescribed Articles. The standard that the RCD applies to is based on AS/NZS equivalents of EN60730 and EN60742m with amendments for local conditions. For example, Australian flammability standards are tighter than equivalent European standards. Products labelled with the RCD $________ or please debit my  Bankcard    Visa    Mastercard Card No: ________________________________ Card Expiry Date ____/____ Signature ________________________ Name ___________________________ Address__________________________ __________________ P/code_______ 20  Silicon Chip Table 6 Arc welding machines Bread toasters Clothes dryers Automotive battery chargers Immersion heaters Microwave ovens Portable drills Extra low voltage power supplies Projectors Residual current devices Swimming pool equipment Vacuum cleaners symbol are also required to comply with the Australian/New Zealand EMC directive and there­fore do not have to be labelled with the C-Tick symbol as well. If a product has LVD/CE approval, gaining RCD approval requires additional testing where AS/NZS standards differ from European standards. Once tested, a submission is made referencing the AS/NZS equivalent of the IEC standards, together with a report of additional tests carried out to obtain either a cer­tificate of suitability or type approval from the regulating body. Standards Australia publishes a brochure that explains the procedure for obtaining RCD compliance, entitled “The Regulatory Compliance Mark – Your Questions Answered”. The Machinery Directive The Machinery Directive is really on the fringe of elec­tronic products but can be applied to cooling fans and or item other moving parts which pose a hazard to fingers, etc. It is mainly applicable to machines where human safety must be main­ tained. Power tools are examples that come under the Directive. Standards of the Machinery Directive include: EN61496 - Safety Of Machinery; EN62061 - Safety OF Machinery - Functional Safety Of Electrical, Electronic and Programmable Control Systems For Machinery; and EN62043 - Safety Of Hand-held Battery Powered Motor-Operated Tools and Battery Packs.