| | Q: Why must we achieve EMC?
A: Other than the fact that products which do not comply cannot be marketed legally in the EC, more disruptive manifestations exist that can affect the way in which we lead our lives. These encompass health and safety issues, the security of data processing, and the functioning of electronic equipment. ABS braking systems, engine management systems, telecommunications and data transfer plus the security of both commercial and military data could all be readily compromised without adequate screening. |
| | Q: What are the main sources of EMC problems ?
A: In all cases there has to be a source and a victim for a path to exist thereby permitting a radiated or conducted coupling. RF interference (sometimes referred to as RFI), more correctly known as Electromagnetic Interference (EMI), results from the operation of electrical or electronic devices involving rapidly changing voltage or current levels and which cause the generation of electromagnetic energy at discrete frequencies and over frequency bands. |
| | Q: What are some sources of electromagnetic emissions (EME)?
A: There are two main sources of emissions: Radiated Emissions (Examples: power lines, pulsed circuits, and improperly designed electronic systems). Conducted Emissions (Examples: switching transients, motor noise on the power lines, RF on the power leads). |
| | Q: What is conducted interference?
A: These interference signals move from one point to another on the power supply leads between a source and a receptor. Two possible sources of these signals are (1) the circuits within the device and (2) radiated energy induced onto the wires of the device. |
| | Q: What is radiated interference?
A: Radiated Interference: These interference signals are transferred via an electromagnetic (EM) field produced by a signal source over a propagation path through the air. The source of these signals can be external (e.g., radio and TV stations) or internal (e.g., unshielded radio frequency (RF) circuits and switching power supplies) to an electronic system. |
| | Q: What is considered as a public low-voltage distribution system ?
A: Public low-voltage distribution systems are power supply systems allowing the direct connection of equipment with rated voltages between 200 and 260V (single phase or phase to neutral for three phase systems) or between 340 and 450V (phase to phase in case of three phase equipment). Higher voltage distribution systems, which are connected to power substations, are not considered to be public low-voltage systems in the above sense. |
| | Q: Why are machines without exposed hazards covered under the Machinery Directive?
A: A machine that has moving parts that are not exposed does fall under the Machinery Directive. A possible solution to the hazard may be a guard; however, the machine is still covered by the Machinery Directive. This hazard and solution must be documented in the Hazard Analysis file. |
| | Q: I use a power supply in my system. Does it require a CE Mark?
A: ower supplies come in many forms. If you are using it in a system then the system as a whole, at least, is tested for EMC and electrical safety. This process will also test the power supply.Hence there is no requirement for a CE Mark on the power supply alone as it is a component in your system. |
| | Q: What is CE Marking?
A: CE Marking is the mechanism by which a manufacturer declares that their product complies with all the relevant European Union Directives |
| | Q: What products require CE Marking?
A: The CE mark is mandatory on all products covered by a EU directive. You will need to establish which, if any, of the "New Approach" or the older "Global Approach" Directives are applicable to your product. Wemtech can help with this process. |
| | Q: What does CE stand for?
A: The initials "CE" may have originally stood for "Conformite Europeen", although nowadays it's just a concept of conformity that has been adopted across the EU |
| | Q: What does CE Marking mean for my product?
A: CE Marking on a product indicates to governmental officials that the product may be legally placed on the market in their country, facilitating the Free Movement of Goods in the EEC |
| | Q: Where must I display the CE Mark?
A: The CE Mark must be displayed in at least one of three places- on the product itself, on the packaging or in the manuals or other supporting literature. It is of course possible to display it one more than one or all of these places. |
| | Q: Who enforces CE Legislation in the UK?
A: Consumer goods are enforced by local Trading Standards Departments, and products used in the workplace by HSE. Medical and Automotive products are covered seperatly by the Medical Devices Agency and the Vehicle Certification Agency. |
| | Q: Who are the members of the European Union?
A: Austria, Belgium, Denmark, Finland, France, Germany, Great Britain, Greece, Ireland, Italy, Luxembourg, Netherlands, Portugal, Spain, and Sweden |
| | Q: What is EMC?
A: Electromagnetic compatibility is an essential feature of any specification for electrical equipment. It is defined as the ability of electrical and electronic equipments, sub-systems and systems to share the electromagnetic spectrum and perform their desired functions without unacceptable degradation from or to the specified electromagnetic environment. |
| | Q: I have recently purchased a number of desktop computers. All function ok, BUT, There is a slight jumping of the screen on two of my units. I am advised that this could be due to the fact we are next door to a large electric supply transformer.
A: It could very well be the case. The 'frame amplifier' used on the monitors are sensitive to 50Hz interference as they use a 'phase locked loop' system to hold the screen steady.There are no low cost technical solutions to this problem. Try changing the tube type monitor to a TFT flat screen type, or try moving the monitors to an area where the problem goes away. |
| | Q: My company officers refuse to produce the documentation required for their products. What do I do?
A: Most products on the market today must be CE marked before placing on the market. Your company officers are legally liable personally, (they cannot hide behind the Ltd liability of the company), to any accident that may occur with their products.There is also a legal responsibility to have documentation available to prove the products are satisfactory and safe to place on the market. I suggest you write an internal memo to the managing Director advising him/her of the requirements. |
| | Q: I have a 12V electronic produced that is going to be fitted on railway rolling stock. I have been told that the applicable EMC standard for my railway product is EN 50121, but this standard is not listed in the Official Journal, do I have to CE Mark?
A: This situation can be confusing, but the answer is yes, you should CE Mark against the EMC Directive. The rationale being because the equipment is within the scope of the EN 50121 EMC standard.However, because this standard is not yet in the official journal you will have to go down the technical construction file route and involve an external Competent Body. |
| | Q: I have a lot of product variants, do I have to produce a Declaration for each one of them?
A: No, you do not have to, you can put all the variants on one Declaration of Conformity (DoC), but ensure you identify them precisely, e.g. with a unique type and/or model number. |
| | Q: I am a manufacture of a valve audio amplifier. This analogue amplifier will have low EMC emissions. I realise I am eligible to do the EMC emissions tests but do I actually have to do them?
A: EMC testing is not mandatory in most cases under the EMC directive. However we would generally recommend that you do some testing to reduce the risk.If you decide not to do the testing then we strongly recommend you to put a rationale in your due diligence or technical file stating the reasons why you are not doing the testing and why you believe the product still complies. |
| | Q: I have recently sourced a mill in India for all my materials for fabricating pressure vessels to the PED, they are ISO approved , Can I go ahead and manufacture, it will reduce my cost base significantly.
A: It is not a certainty that an ISO approved mill is able to provide material for the PED. The ISO certificate will need to be one issued under the MLA that is a consortium of ISO accreditation bodies approved by the EC and other government bodies.If it is not on the MLA list (found on the web), you can not use the materials. You must also keep in mind that the this is the first step in validation of material, you will need to choose the Harmonised, EAM or PMA routes as set down in the PED. |
| | Q: I have purchased new casting machinery and it has arrived with the appropriate D of C. The body that carries out my PSSR work, will not enter the equipment into the WSE as the pressure vessels are not CE marked, are they correct?
A: The body is correct, the pressure vessels should be individually CE marked in their own right, and have the appropriate paper work. If you place them into service, the company is in breach of the PER, and liable to prosecution under the act. |
| | Q: Is it possible to have a Notified Body carry out CE marking on my completed pressure vessels so that I can use them and avoid prosecution?
A: It is not possible under your circumstances to retro CE mark you pressure vessels for the following reasons:No record of welder’s qualification
No record of approved weld procedures
No design data
No material traceability
In other words no evidence that the vessels comply with the Essential Safety Requirements of the PED. |
