How do you do pre compliance testing ?

[GeekGirl]

Hi all,

This is more for the Pro EE's,

How do you do the pre testing for things like CE etc.

I am starting to design products that will need to be CE etc certified.

I want to keep the tests at the test house to the minimum number, so I am looking at running some basic tests so chance of first time pass is high.

[Valhallasmith]

Pretty easy, just get a copy of the standards you need to meet and test to them.  I did it for UL compliance a number of years ago and while the standards can be obtuse they are not impenetrable.  Read through them and decide which are time and cost appropriate.  Building some basic fixturing here and there is fine but probably not worth over doing if you don't frequently have new products that needs compliance testing.  Having a number of timers, loads and a variac is handy.  A thermocouple meter, spool of wire and a thermocouple welder are very handy as well. 

Thats a short list but there are tons of things that would be handy. 

[qno]

Hi Kat,

What do you need to test?
A lot of compliance fuss can be skipped if your product operates on low voltage < 42VAC or <60 VDC.
What is it? Is it connected to the mains? How much power does it consume? Is it lighting, computer equipment for use in the industrie or at home. How are you going to dispose of it at EOL?

My experience:
If you use a powersupply use one with UL and CE certification. This can save a lot of money and time.
UL supplies a "yellow card" to a producer of safety critical components. For example if you use a capacitor in a powerline filter the manufacturer of the capacitor must be able to send you a copy of this card.
There is an extensive procedure for the manufacturer to get this card and to keep it.

[Neilm]

Hi Kat,

First thing to remember when selling into Europe is that the company that imports the product into Europe is responsible for verifying the product meets all the required standards. That being the case the cheapest way is not do any testing stick a CE badge on it and hope that the importer does all the work. I wouldn't recommend that approach as there have been several cases here in the UK where warnings have been issued and fines imposed when the products had been falsely badged.

Depending on the product, it may have to meet several standards. These broadly fall into two categories, safety (Low voltage directive, Machinery directive) and EMC compliance. Certain niche products may have performance standards. Which standard applies may dictate how much testing you have to do. The business I work for designs and makes electrical test equipment for sale world wide, so I am mostly familiar with the IEC61010 (test and measurement equipment) and IEC61326 for EMC. The former standard requires a large checklist to be filled in which goes into great detail of all aspects of the design of the product - both electrically and mechanically. The latter standard allows at least two ways of compliance. The first is a technical argument - essentially a large document showing that the product is compliant. The strategy used at my company is to do a complete set of tests on an instrument to prove it is compliant. this is made easier as 15 years ago the company spent £250,000 buying the required test gear. That being said, there is no reason you could not do some pre-compliance tests using a spectrum analyser with a decent set of probes. I have also seen a hand held noise generator that simulated the susceptibility tests available in the UK (http://www.empulse.co.uk) Unfortunately it is not available outside the UK.

If you are worried about EMC testing remember to use good signal integrity on the layouts (Power and ground planes are a must).
There are  several good resources on line. One very good resource I use is the Compliance club articals. (http://www.compliance-club.com/). Look for the past entries from Keith Armstrong for simple tips and tricks to PCB layout and circuit design. I have used these articles to help in the past and found them invaluable. My last product passed the EMC compliance tests full time.

Finally, remember that just because you bought a standard at the start of the project it may have been superseded by the end of the project. Some of these may not have grandfather clauses - so any instrument sold under the old standard will have to be reassessed (and possibly retested) to meet the new standard. A good test house should be able to advise you whether the standards you are testing to are under revision. If it is a European standard then the Cenelec website (www.cenelec.org) will show it.

One last thing to note - my first experience of EMC was when I was part of a small team. We bought a four power supplies to run in parallel - mains in to 28V out as the manufacturer stated they could be used. When we did the compliance test we failed it as when all four supplies were running they produced too much conducted noise. A large filter had to be put in to fix the problem. The moral of this is that using products marked CE does not necessarily mean that the final product will pass.