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Electrical / EMC

The first important point of electrical and EMC testing is that a large portion of the so-called test is not a test at all.  It is a visual inspection to see if you have the correct symbols and words in your device labels, operating and service manuals, etc.   Your equipment may pass the real tests, described below, but if the paperwork is not in order, you still fail the testing and you won't have the proof that you need for either the USA 510(k) or European CE Mark technical documentation.  To help you understand and plan your electrical safety project, click here.

Electrical tests consist of leakage current, ground impedance, and dielectric withstand.  Leakage current is the current flowing between a conductive metal surface (the chassis or case) and ground (in the rest of the world it's called "earth"), with a variety of wiring problems such as hot and neutral switched, the ground conductor disconnected, etc.  Ground impedance is the impedance between the conductive metal surface and ground again with a variety of wiring problems.  Dielectric withstand can be the most destructive of the tests.  This tests the insulation properties of your device power supplies by putting a voltage in excess of 20 times what would be expected (so, for example, 2,500 VAC on a line expecting 120 VAC, to see if the power supply can "deal with this".

EMC tests involve radiated and conducted emissions and immunity.  For CE Marking as of November 1, 2004, successful testing to the revised EMC test standard (EN IEC 60601-1-2:2001) will be required.  The revised test standard may be more difficult to conform to depending on the type of device, particularly if the device is life supporting.  Learn more about this by clicking here.  EMC compliance generally means that your product passes four forms of EMC testing:  Radiated Emission, Conducted Emissions, Radiated Immunity, and Conducted Immunity.  Radiated emission testing addresses how much EMI/RFI your device is putting out into the air, as picked up by essentially a radio antenna.  Conducted emissions involve looking at your power line and seeing how much EMI is being sent back down from your device to the outlet and other devices in the room.  Radiated immunity testing is how your device deals with EMI/RFI in the air - for example, what happens to your T.V. when the neighbor mows his lawn right by your living room window?  Conducted immunity is how your device reacts to EMI/RFI passed over the power line from another, such as when someone (notice we didn't say wife or husband) is vacuuming in another room and you are trying to listen to your radio. 

The CRO Group experts can help you with the most important part of this testing -- assessing the product design and making recommendations so you won't have to pay for testing TWICE.  We can also recommend accredited test labs which specialize in your type of device, or have short queue times, or are the least expensive, or who, if you're convinced there is no redesign needed -- will add "fixes" during the test to save you time and money if the inevitable happens.  

Finally, it is important to know that when you submit a product for testing, it is not just testing with meters that is performed.  Before a single meter is applied, a substantial portion of the "test" is assessment of conformance with applicable labelling requirements.

If you are interested in doing your own preliminary check on how well your product will do, click here.  If you would like more information on our services to support successful testing, click here.

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