Hi , By coincidence i was just checking out PTI when your e-mail came in. Here's what I found. The tracking index is determined by placing 2 electrodes 4mm apart on the laminate surface (no copper). A voltage is applied to the electrodes and an electrolyte (0.002% NH4Cl) is dropped between them. The CTI is determined by setting a selected voltage and carrying out the test for 50 drops until a current of 0.5A flows for more than 2 seconds (i.e. failure). The voltage is adjusted up or down until the maximimum voltage is established at which no failure occurs at 50 drops. This numerical value is the CTI, provided no failure occurs below 100 drops when the voltage is reduced by 25 volts. For the PTI the test is carried out at the specified voltage, the specimen shall withstand 50 drops without failure. Clear as mud. If you would like more info let me have your fax No and I will send it to you. > ---------- > From: th_yeo[SMTP:[log in to unmask]] > Reply To: TechNet E-Mail Forum.;th_yeo > Sent: 16 July 1999 01:11 > To: [log in to unmask] > Subject: [TN] Proof tracking index (PTI) and comparative tracking > index (CTI) > > Hi, > > Are the above the same? Do not understand the meaning of maximum > voltage > and proof voltage. > > Appreciate feedback. > > Regards, > > ############################################################## > 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. > If you need assistance - contact Gayatri Sardeshpande at > [log in to unmask] or > 847-509-9700 ext.5365 > ############################################################## > ############################################################## 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. If you need assistance - contact Gayatri Sardeshpande at [log in to unmask] or 847-509-9700 ext.5365 ##############################################################