I read in !emc-pstc that cherryclo...@aol.com wrote (in <17d.557eff5.29c a1...@aol.com>) about 'Pro-audio and ground lifting', on Wed, 20 Mar 2002: > Class I equipment uses basic insulation plus protective ground bonding to > protect against electrical hazards, and must use three-pin mains > connectors > and three-core mains leads (for single-phase supplies). > > The only alternative permitted (in Europe, anyway) for mains-powered > equipment is Class II - 'double insulation' . This must have no protective > ground conductor and must use two-pin mains connectors and two-core mains > leads (again, for single phase supplies).
This is true for consumer products but for professional audio equipment under IEC/EN60065, an arrangement whereby *parts* of the product meet Class II requirements while other parts meet Class I requirements has been accepted by Notified Bodies for some years. These can be shown to be just as safe as conventional products. With regard to your main enquiry, professional audio engineers in the Audio Engineering Society are severely critical of 'ground lift' solutions. The correct, and safe, solutions, lie in the signal circuits that sustain the ground loops. The subject is extensively treated in the June 1995 issue of the Journal of the Audio Engineering Society. -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Interested in professional sound reinforcement and distribution? Then go to http://www.isce.org.uk PLEASE do NOT copy news posts to me by E-MAIL! ------------------------------------------- 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"
