When a fuse's interrupting (breaking) capacity is too low for an application and the fuse opening interrupts current in a manner that causes the glass to crack or break, the temperature gradient across the glass and the internal pressure created by the plasma when the fusible element vaporized can and will push some of the vaporized metal out of the confines of the glass and contaminate the surrounding area. Sometimes the deposited metal is not readily visible and even if visible does not always clean up easily or well. The Creepage Distances may be compromised. Depending on the overall design, this can cause increases in touch current (leakage current) and otherwise increase the risk of electric shock with continued product use.
Replacement of the fuse can become more frequently necessary due to the contamination allowing unintentional current flow to keep the product operating. If each successive fuse replacement uses the same fuse, more of the same may result. If the product isn't returned for replacement or discarded, the fuse might eventually be replaced with a larger rated fuse with possible further degradation of safety. Peter Tarver This email message is for the sole use of the intended recipient(s) and may contain confidential and/or privileged information. If you are not an intended recipient, you may not review, use, copy, disclose or distribute this message. If you received this message in error, please contact the sender by reply email and destroy all copies of the original message. - ---------------------------------------------------------------- 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 <emc-p...@ieee.org> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. 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 <emcp...@radiusnorth.net> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher: <j.bac...@ieee.org> David Heald: <dhe...@gmail.com>
