Greg - It is important to note that secondary protectors, by definition in both North American and ITU-T specifications, are overcurrent protection devices. I did mentioned that the additional overvoltage protection was included, but not that it was the only protection in the secondary protector.
Assuming the secondary protector is installed correctly, if the overvoltage protection in the secondary protector were to activate (spark over), the secondary protector's overcurrent protection would open the circuit (usually on the order of 350mA, further protecting the premises wiring and terminal equipment. Then the brunt of the power cross would be taken by the primary protector. Regards, Peter L. Tarver, PE Product Safety Manager Sanmina-SCI Homologation Services 2000 Ringwood Ave. San Jose, CA 95131-1749 V: 408-904-2081 F: 408-904-2095 M: 408-234-3529 [email protected] > -----Original Message----- > From: Greg Galluccio > Sent: Friday, December 13, 2002 11:50 AM > > Pete Tarver pointed out that: > > >>>The primary protector at a building entrance > limits the voltages available > to do harm to 600Vrms (assumed sinusoidal). > There might also be > secondary protection on telecommunication lines > that include > supplemental overvoltage protection that limits > the voltage > downstream to even lesser levels.<<<< > > Another concern is that in the event of a > lightning strike or power cross, an > overvoltage device on the equipment side rated > lower than 600 V will fire > before the 600V outside protector, shunting all > follow-current through the > unprotected premesis wiring and through the > equipment itself. > > > Greg Galluccio > www.productapprovals.com > > ------------------------------------------- > 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: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: [email protected] Dave Heald: [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] 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" ------------------------------------------- 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: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: [email protected] Dave Heald: [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] 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"
