----- Original Message ----- From: "John Woodgate" <[email protected]>
> It seems strange that the connector on a cable needs no fire enclosure but > the fixed connector into which it fits does need one! How do you plug > anything into it through the enclosure? I don't know. I'm asking you, experts here. If you have the fire enclosure I see no problem, but elsewhere I don't know. I have read 60950-1:2001, and later 60950-1:2006 trying to understand what is important for me as a designer. Some problems I found I have tried to solve asking here. This was one of the problem. As I found no solution I have also asked one accredited lab if I connect the cable directly to PCB (no connector) and first element would be 0.5A PTC can I assume all elements at my PCB are powered by LPS. The answer was : No. I understood that the problem for them was that PTC doesn't disconnect the current permanently. When I tried to be more specific I got no answer. Someone from here (EMC-PSTC) told me (out of list) that PTCs are not recognised as fuses and I must use fuse. Trying to be in accordance with 60950-1, I have redesigned our next product (we just did 3 prototypes with connector for cables) to connect cable directly to PCB (connecting points in my opinion are not elements) and used fuse as first element (my contract manufacturer told me that SMD fuses are no popular, all others use PTCs -> they all must be wrong ;-) ). I suppose that way all elements at my PCB are powered by LPS, but what with this fuse? Is it powered by LPS or no? Is it limiting power for itself or not ? If it happens that its first pin will be shortened to ground there will be nothing (except cable resistance) to limit the power. I am now starting to write the instruction to it. Should I write there to use only LPS power supply ? Or should I look for cable mounted fuse to add to my device. This device is powered by 12V DC and consumes 0.3A. You can say it is not under LVD so no need for 60950-1. I'm not sure but I suppose that if not under LVD than under GPS and logical way to check safety would be 60950-1. But if it happens that the 12V DC powered device is under R&TTE (high probability nowadays) than it is under LVD and it looks that it must have fire enclosure or ask for LPS in instruction. If you know the solution I can't find since few years please let me know. Best Regards Piotr Galka - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]>
