Rich, According to Table 6-1, column A7 in IPC-2221 (Appendix A, Table 6-1 in IPC-A-610C), the solder deposit cannot reduce the minimum electrical spacing below 0.13mm, for voltage potentials of 0-100V (AC/DC peak) between non-common conductors, for operation at any elevation, if the assembly is to be conformally coated. For Class 3, the solder deposit / ball must also be attached / fused to a metal surface, fully encapsulated by the coating, and shall not be capable of being dislodged during exposure / use in normal service environment. Bob -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Richard Kraszewski Sent: Tuesday, July 27, 2004 8:37 AM To: [log in to unmask] Subject: [TN] Allowable solder balls on a component? What is the largest solder ball I am allowed that would not violate minimum electrical clearance? I am working within class 3 requirements. The component in question has 9.6mm spacing from the edge of one pad to another. Eventually this assembly will be conformally coated. I've turned to A-610, section 12.4.10 but it presents me with this "minimum electrical clearance" question, and it's appendix 1 doesn't seem to be of much help. Any thoughts would be truly appreciated. Rich K --------------------------------------------------- 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 847-509-9700 ext.5315 ----------------------------------------------------- --------------------------------------------------- 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 847-509-9700 ext.5315 -----------------------------------------------------