----- Original Message ----- From: "Nick Rouse" <[email protected]> To: "FRIES" <[email protected]> Sent: Saturday, September 30, 2000 9:49 PM Subject: Re: Getting Started
> > ----- Original Message ----- > From: "FRIES" <[email protected]> > To: <[email protected]> > Sent: Friday, September 29, 2000 3:35 PM > Subject: Getting Started > > > > > > > > Dear Group, > > > > I'm just getting started in the world of EMI and would like to ask a few > > questions. I'm not sure if I should be going the TCF route or the > Standards > > Route. The company that I work for manufactures products which have many > > variants. > > > > > > 1) Is it EC law that a manufacturer must perform EMI testing before > > applying the CE mark? > > Very strictly speaking No but in practice yes in almost all practical > cases. > If you could show by theoretical grounds that a piece of equipment neither > caused or was susceptible to interference or had results from very nearly > identical equipment that met the standards by a wide margin and could > persuade a competent body of this fact and get him to sign the TCF that > gave these augments you could legally apply a CE mark on the basis of > that TCF. In practice however, interference being such sneaky unpredictable > stuff, you would only have a chance of so convincing a competent body > in very exceptional cases since he would bear legal liability for results of > signing of the TCF if he had not shown competence and diligence. > Such people tend to be a cautious breed. > > > > 2) If a manufacturer follows the Standards Route, does EC law > >require each variant to be tested? > > Yes if there is any possibility that the variants may have different EMC > characteristics. > This is one of the great advantages of the TCF route. In you can persuade > the competent body that a particular variant is the worst case or that tests > on > a subset of the variants cover the EMC properties of all variants you can > greatly reduce the burden of testing. > > > > 3) If, when testing, the limit is exceeded, can the CE mark still be > > applied? > > If you are using the harmonised standards route clearly no. The application > of the CE mark has the legal effect of being a statement by the manufacturer > that the equipment meets the requirements of all European directives that > require such marking and are applicable to that product. To place equipment > on the market, or to take it into service in the European Economic Area with > an invalid CE mark is a serious offence. If you take the TCF route the > answer is again theoretically you might be able to, but in practice it is > most unlikely. The competent body only has to sign that the equipment meets > the > fundamental protection requirements of clause 4 of the directive and these > are expressed in simple qualitative terms. The competent body is > theoretically not bound by any standards, tests or measurements and > can accept any evidence he judges valid and can ignore any evidence > if he is convinced that the protection requirements are met. In > practice however they most unlikely to sign a TCF if the equipment > fails one of the standards unless there are very exceptional circumstances > (like for instance if the equipment by its nature can only be used in > locations remote from any other equipment.) > > > > 4) Are the services of a Competent Body required in order to put together > a > > TCF or can the manufacturer do that on his own? > > No. You are in theory free to do all the work yourself and take it along > for him to sign on the dotted line. However, since the main reason for using > the TCF route is that you don't want to use the straight harmonised > standards, > it is likely that the TCF will contain some arguments as to why the > fundamental protection requirements can be meet by some means other > than straightforward application of the harmonised standards. It will be > down to his judgement as to whether these arguments are valid. It is a bit > risky to present these arguments to him cold. It is a much better idea to > contact your > chosen competent body before you start any testing and get an idea of what > he will accept and what format he will want the TCF in. > He may well have some pre-written paragraphs available for a fee that > will allow you to "boilerplate" together a TCF that works out cheaper > than doing it all yourself. > > Hope this Helps > Nick Rouse > > > > > > Thanks in advance, > > Joseph C. Fries > > > > ------------------------------------------- > > This message is from the IEEE EMC Society Product Safety > > Technical Committee emc-pstc discussion list. > > > > To cancel your subscription, send mail to: > > [email protected] > > with the single line: > > unsubscribe emc-pstc > > > > For help, send mail to the list administrators: > > Jim Bacher: [email protected] > > Michael Garretson: [email protected] > > > > For policy questions, send mail to: > > Richard Nute: [email protected] > > > > > ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: [email protected] Michael Garretson: [email protected] For policy questions, send mail to: Richard Nute: [email protected]
