PC traces are easier to assemble and the assembly can be done in a tighter space. I think (just an opinion) that proper design could make this type of system more reliable as well with less chances of wires coming loose...
> -----Original Message----- > From: Lou Aiken [SMTP:ai...@gulftel.com] > Sent: Tuesday, February 04, 2003 11:36 AM > To: Peter L. Tarver; emc-p...@majordomo.ieee.org > Subject: Re: EN60950 protective conductor test (was Re: Circuit Breaker Tripping Dring Fault Tests) > > > Why not provide a fuse to prevent deterioration of the PE trace on a PCB? > > Joking of course, but now that I have your attention, I would like to see > this thread move away from the physics and discuss what practical reasons > there are for using PC traces to provide earth fault circuits. > > > Lou Aiken, LaMer LLC > 27109 Palmetto Drive > Orange Beach, AL > 36561 USA > > tel ++ 1 251 981 6786 > fax ++ 1 251 981 3054 > Cell ++ 1 251 979 4648 > ----- Original Message ----- > From: Peter L. Tarver <peter.tar...@sanmina-sci.com> > To: <emc-p...@majordomo.ieee.org> > Sent: Tuesday, February 04, 2003 9:53 AM > Subject: RE: EN60950 protective conductor test (was Re: Circuit Breaker > Tripping Dring Fault Tests) > > > > Not quite. I^2·t will tell you the let through current of > the copper trace, but will not necessarily tell you if the > construction will be compliant. The compliance criteria for > this test include: > > * no damage to the trace (no lifting, probably no > discoloration) > * no damage to the PWB (no delamination, burning; I don't > know if this includes burning off of solder mask) > * before and after earthing impedance must comply with the > 0.1 Ohm maximum impedance > * no change in earthing impedance greater than 10% of the > before and after earthing impedance results > > There is also the much more variable solder in the earthing > path. While manufacturing techniques have come a long way > in terms of consistency, the amount of solder in a joint and > the quality of the joint itself can play a significant role. > It should be expected that a lower melting point solder will > perform less well than a higher melting point solder. > Appropriate process controls will have a positive effect. > > These are some of the reasons some form of safety agency > factory auditing of this type of construction is normal. > > > Regards, > > Peter L. Tarver, PE > Product Safety Manager > Sanmina-SCI Homologation Services > San Jose, CA > peter.tar...@sanmina-sci.com > > > > -----Original Message----- > > From: Chris Maxwell > > Sent: Tuesday, February 04, 2003 5:32 AM > > > > > > Exactly! > > > > Chris Maxwell > > > > > > > -----Original Message----- > > > From: drcuthbert [SMTP:drcuthb...@micron.com] > > > Sent: Monday, February 03, 2003 7:50 PM > > > > > > What is needed is the I squared t rating of the > > breaker. Then the (I^2)(t) > > > rating of the PCB. Then you know if the PCB can > > take it. > > > > > > Dave Cuthbert > > > ------------------------------------------- > 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...@attbi.com > > For policy questions, send mail to: > Richard Nute: ri...@ieee.org > Jim Bacher: j.bac...@ieee.org > > Archive is being moved, we will announce when it is back on-line. > All emc-pstc postings are archived and searchable on the web at: > http://www.ieeecommunities.org/emc-pstc > > > > > ------------------------------------------- > 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...@attbi.com > > For policy questions, send mail to: > Richard Nute: ri...@ieee.org > Jim Bacher: j.bac...@ieee.org > > Archive is being moved, we will announce when it is back on-line. > All emc-pstc postings are archived and searchable on the web at: > http://www.ieeecommunities.org/emc-pstc 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...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
