Group, This topic has resurrected a question I have always had about AC Mains Power in Europe. I have always believed that 230Vac in Europe is derived from 3-phase. I could see where a home or small business might be powered only by a single phase, but wouldn't a large company or factory be powered by 3-phase and to which a single room or lab would most likely have receptacles powered by different circuits on different phases of the 380V?
Also, surge pulses can be cause by many sources that do not make the surge common mode to an entire building, so it is most possible that a "System" can see a surge on one power cord and not on all power cords. Here is the States, our homes are generally powered by Split Phase AC where the receptacles within the same room are on different circuits and different phases. In Canada, it is common to have two phases of 208 powering 115V receptacles within the same dual receptacle. Here at work within our lab (in the States), our 230V high powered equipment is powered by its own dedicated 230V L-L circuit derived from a 230V 3-phase transformer. Each 230V receptacle has its own circuit and which could be on different L-L phases. Lower powered 230V equipment is powered off a different transformer and all of our 115V receptacles throughout the building is powered by one of 3-phases Line to Neutral circuits derived from 208V 3-phase. It is common for adjacent 115V receptacles to be on different phases. So a typical system setup in our work area is almost guaranteed to powered by different circuits, different phases, and different transformers within our company's multiple source power system. BTW, we also have lighting powered by 277V derived from L-N on our 480V 3-phase power which comes right off the pole. This 480V 3-phase powers the entire building including all of our transformers. Is this type of power distribution not common in larger facilities within Europe? The Other Brian From: Larry K. Stillings [mailto:[email protected]] Sent: Wednesday, January 02, 2019 5:16 PM To: [email protected] Subject: [PSES] IEC 61000-4-5 Surge Testing Single plug vs. multiple plug system All, I received the following email from a customer today via their customer addressing our application of surge testing. We are testing laboratory equipment per IEC/EN 61326-1 and IEC/EN 61326-2-6 and specifically are having failures with respect to surge on a system that has multiple power cords. We are testing one power cord at a time. Here are their comments we have never tested a system comprised of multiple instruments in this way before. i.e. applying surge to one unit at a time - we have always, with agreement from our customers, applied surge (and in fact all tests) to all of the units plugged into e.g. a mains distribution block all at the same time. Especially for surge, it seems unlikely that in the real world any real surge on the mains supply would not affect all things in a system as it is very likely they are all plugged into the same mains circuit in e.g a particular room. To further bolster this, we have made comment to customers in the past that it could be noted in the manual to ensure this is the case. By applying surge to all units at the same time, we maintain all of their supply voltages at the same level. I can see how, by applying a surge to a single part of the wider system, communications issues could occur as suddenly the points of reference (i.e. reference voltages) for different parts of the system could be pulled away from each other by the surge. Testing a system by applying the tests to all at once, rather than a single item at a time, isn't necessarily an "easy way out" either. For other tests e.g. conducted emissions, where noise transmitted from the unit under test back onto the mains supply is measured, passing is made more difficult by measuring all units at once. Where in this case one at a time would be much more favourable. Our test house has always advised that we can choose, either all tests one at a time, or all tests applied to all through a mains block, but we cannot mix and match between different sections for the conducted EMC tests. I know this brings up all sorts of questions, however I would like to focus on the surge testing at the moment. I am pretty sure at least one of the standards says conducted emissions shall be tested on each port individually, but we don't need to go there right now ;-) Thoughts when you get responses like this? Larry K. Stillings Compliance Worldwide, Inc. Test Locally, Sell Globally and Launch Your Products Around the World! FCC - Wireless - Telecom - CE Marking - International Approvals - Product Safety 357 Main Street Sandown, NH 03873 (603) 887 3903 Fax 887-6445 www.complianceworldwide.com<http://www.complianceworldwide.com> Privileged/Confidential Information may be contained in this message. If you are not the addressee indicated in this message (or responsible for delivery of the message to such person), you may not copy or deliver this message to anyone. In such case, you should destroy this message and kindly notify the sender by reply email. 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