Are the contacts switched (made or broken) dry (no current flowing)? That may have some effect. Blair >>> [log in to unmask] 02/11/05 06:25AM >>> Well, it depends: this is a matter of high power circuitry, and the concerns of low signal are less relevant. Check you loads: capacitive or inductive loads require high stress factor, and may need protection networks. Resistive loads do not need it. Check the count of the make and break cycles, and verify the limits according to the load characteristics. Regards Ofer Cohen Manager Quality Assurance, Reliability and Production Technologies Seabridge Ltd. - A Siemens Company -----Original Message----- From: TechNet [mailto:[log in to unmask]]On Behalf Of - Bogert Sent: Friday, February 11, 2005 01:39 To: [log in to unmask] Subject: [TN] Calculate current capacity for electrical contacts February 10, 2005 How does one determine what current can be carried by electrical connector contacts to determine capability to carry about 80 AMPs (RMS), low freq AC, or DC. We have an application that uses a carbon steel base metal pin contact. The contact is given a nickel flash, followed by a copper plating (to fill in small voids), followed by another nickel flash, followed by silver plating. Does one calculate current capacity from just the carbon steel base metal, or does one need to take the plating into account? What formula or chart is used to support the calculation? If the nickel flash thickness is increased, will it impact current capacity? If plating is changed to gold, does that impact current ******************************************************************* This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you have received this email in error please notify the system manager. This footnote also confirms that this email message has been swept for the presence of computer viruses. www.hubbell.com - Hubbell Incorporated --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------