The inability of Schuko plugs to be able to be polarized, may have something to do with the fact that German homes (at least) are supplied with 3-phase power. Some time ago this came as a surprise when a friend was showing me his new lathe he had just installed in his basement, which used a 3-phase motor. When I asked how he managed to get 3-phase power installed in his house, he gave me that "what planet did you come from" look, and said that this is how power is delivered to all residences there. My recollection from our conversation is that at least some of their domestic 3-phase power systems use the Delta configuration, so outlets are connected across 2 of the 3 phases. Thus, there is no neutral or "polarity". I wonder if anyone can verify if they use a Delta or a "Y" connection?
Bob Wilson TIR Systems Ltd. Vancouver. -----Original Message----- From: Allen, John [mailto:john.al...@uk.thalesgroup.com] Sent: February 21, 2002 12:32 AM To: Robert Wilson; emc-p...@majordomo.ieee.org Subject: RE: South Korean Power System & Schuko Plugs Hi Folks A few years ago I worked for BSI "Technical Help to Exporters" and helped to update their publication "World Wide Plugs and Sockets Survey" - which I assume is still available from BSI (see www.bsi-global.com) I remember looking at the Korean standards for plugs and sockets:- Yes - they were/are variations of Schuko types(both with and without earthing contacts), but I also seem to remeber some NEMA (USA/Canadian) types as well. However, as part of another large exercise for a customer I reviewed many of the European wiring rules standards to identify any conventions or requirements for the polarity of wiring-up of sockets - notably those that accept the various versions of the (generally reversible) Schuko plugs and also the somewhat similar Danish, Swiss and Italian plugs. Result : there were (and presumably still are) wiring colour codes for the building wiring to these sockets - BUT NO CONVENTION AS TO WHICH COLOUR IS CONNECTED TO WHICH CONTACT TUBE OF THE SOCKET, apart (obviously) from the requirement that the Green/Yellow insulated conductor be connected to the earthing contact. Therefore you must always assume that the Line/Neutral polarity of the wall socket is random - this is also true for the French version of the socket with the earthing pin projecting out since it is only a (more recent?) variety of the type of socket which has no such pin. Thus the equipment connected to it must have some sort of double-pole disconnect device (be it a switch, or the plug itself). Double-pole fusing requirements may depend on the product standard requirements, but is effectively required where the internal wiring of the equipment cannot deal with the full prospective fault current available from the wall socket. Hope this clarifies matters. Regards John Allen Thales Bracknell, UK. ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on "browse" and then "emc-pstc mailing list"
