It's simply the hotter! Current causes the heat, so wherever the highest current density combined with the lowest heat dissipation capability is where it will fuse first. Wayne -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Victor Hernandez Sent: Friday, May 15, 2015 4:14 PM To: [log in to unmask] Subject: [TN] PWB Exothermic event Fellow TechNetters: During an exothermic event is it the Positive, Plus, stimulus copper that fuses OPEN or is it the NEGATIVE, Gnd, copper that fuses OPEN. Victor, ______________________________________________________________________ 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] ______________________________________________________________________