Hello Lyon, you can refer to the IPC 2221 or IPC A-610E on Appendix "A" an the last pages of the standard. Best regards. Francesco Francesco Di Maio IPC e Formazione IPC A-600, IPC A-610, IPC 7711/21 Certified IPC Trainer Via Kennedy Ingresso 2, 20871 Vimercate (MB) - Italy Desk: +39.039.639.5921 - Mobile: +39.335.5693650 - Fax: +39.039.639.5051 E-Mail:[log in to unmask] GEST Labs S.r.l. a Socio Unico Lyon Yuan <[log in to unmask]> Sent by: TechNet <[log in to unmask]> 08/10/2013 15.47 Please respond to TechNet E-Mail Forum <[log in to unmask]>; Please respond to Lyon Yuan <[log in to unmask]> To <[log in to unmask]> cc Subject [TN] minimum electrical clearance Guys, How to understand the minimum electrical clearance in IPC? Lyon Yuan ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________ ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________