As you say, you have several types of EUTs, and each type must be tested as the EUT. Any other equipment connected to the EUT with cables are considered to be auxiliary equipment. The standard is clear on how to test the EUT when auxiliarly equipment is attached. In your case, the procedure has no knowlege that there is a loop and does not care. All it knowns is that a surge is being applied to a cable. I am sure that there are many ways one could devise to test one or more EUTs at the same time; however, in the end, if you are claiming compliance to a standard, you must test according to the procedure in the standard. If you wish to do otherwise, then you will have to peruse the Technical Construction File route.
Richard Woods Sensormatic Electronics Tyco International -----Original Message----- From: [email protected] [mailto:[email protected]] Sent: Wednesday, March 20, 2002 4:59 AM To: [email protected] Subject: Surge test on a loop Hi all, Assume a fire alarm detection system. 10 smoke detectors are connected in series on a loop and both ends of the loop is connected to the fire alarm panel. Shielded cable is used and the shield is connected through the whole loop. So, how do we carry out the surge test on the loop? The alarm panel and the detectors are all EUTs. As far as I understand IEC61000-4-5:1995 chapter 7.5, I will insert an extra 20 meter shielded cable between each detectors and then I will drive the surge pulse onto the shield in order to test one of the detectors. Then I move the extra 20m cable to the next detector and surge test it. If this is correct, why can't we just put the surge pulse onto the shielded loop and assume that the whole loop was tested at once? Best regards Amund Westin, Oslo/Norway ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee
