Hello Alexis, IPC-2222 (rigid boards) para 10.1.1 refers to the minimum spacing to non-plated through holes, 'shall not be less than the minimum spacing specified in Table 6-1 of IPC-2221 plus 0.4mm." I usually consider the maximum possible area that the screw head / washer / mounting post / boss will occupy on the board and add the minimum electrical spacing to that. This maximum area should take into account the positional tolerances of the mounting screws, and also the clearance 'slop' of the washers (if conductive) and even the amount that the board itself's position can vary due to the necessary clearance on the mounting holes for the screws. regards, Phil. At 15:22 2/10/00 -0700, you wrote: >I am looking for the IPC recommended clearance of components/traces/vias >to mounting holes with screws. >I can't find it in IPC-2221; does someone out there know where it is? >Thanks in advance for any guidance. > > >******************** >Alexis Meehan >PCB CAD Mgr. >408-328-4595 >[log in to unmask] >LuxN, Inc. >570 Maude Court >Sunnyvale, CA 94085 >"The Optical Renaissance Has >Begun." > > > <http://www.luxn.com/>http://www.LuxN.com Phil Dutton C.I.D. Senior CAD Technician IPC Certified Interconnect Designer Tenix Defence Systems Pty Ltd Systems Division - Adelaide Second Avenue, Technology Park, Mawson Lakes. SOUTH AUSTRALIA 5095 ================================ Phone: (08) 8300 4400 (reception) Fax: (08) 8349 7420 email: [log in to unmask] Internet Page: http://www.tenix.com ================================