Scott, Internal layer breakout is allowed in Class 2 and Class 1 of IPC-RB-276 and the superseding document, IPC-6012, but not at the interconnect. I think that Class 3 in the specification will retain the no breakout condition for some time One of the fears is not just electrical shorts, but potential shorts where spacing is reduced down to 0.001 inch by breakout. The integrity of the interconnection of the completely circumferential annular ring seems to be less of a problem per the ITRI report. Phil Hinton ############################################################## TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c ############################################################## To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TECHNET <your full name> To unsubscribe: SIGNOFF TECHNET ############################################################## Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information. For the technical support contact Dmitriy Sklyar at [log in to unmask] or 847-509-9700 ext.311 ##############################################################