Steve, I never really pay a lot of attention to search engine recommendations, but that will now change. Now I know why all the people defer to your greatness. I will be gladly joining in the 2nd "Steve Day" celebration, Friday March 19th. Kidding aside, thanks for the help. Anne Ledger EMDS, Inc. > -----Original Message----- > From: Stephen R. Gregory [SMTP:[log in to unmask]] > Sent: Thursday, March 18, 1999 1:10 PM > To: [log in to unmask] > Subject: Re: [TN] Comparative Tracking Index? > > In a message dated 3/18/99 7:26:33 AM Pacific Standard Time, > [log in to unmask] > writes: > > << Good Morning TechNet, > > I have a fabrication drawing with a note with the following note. > > Material: .062 laminated glass (woven fabric) base, epoxy resin, > Flame > retardent, FR4. copper clad 2 oz./sq ft. Laminate must be certified > to > have a minimum comparative tracking index of 175. Microsection > demonstrating > compliance with copper weight, dielectric spacing, line width and use > of CTI > 175 or > better material shall be shipped with each lot. > > I am at a loss on the CTI 175 stuff. I have reviewed IPC 4101 and > don't > find a reference. I have placed a call to our material supplier but > no > response yet. The TechNet > seems much faster. Can anyone provide me with a clue? Thanks in > advance for > the help. > > Anne Ledger > EMDS, Inc. > [log in to unmask] >> > > Hi Anne! > > While I'm waiting for a stencil to get here so I can run a job I > got set- > up, I used http://www.dogpile.com search engine to see what I could > find...and > I like to learn more stuff besides assembly junk too. But here's what > it found > for ya': > > Materials are separated into four groups according to their CTI > (Comparative > Tracking Index) as follows: > > Material group I: 600 < CTI > Material group II: 400 > CTI < 600 > Material group III a: 175 > CTI < 400 > Material group III b: 100 > CTI < 175 > > The CTI values above refer to values obtained, in accordance with DIN > IEC > 112/VDE 0303, part 1, on samples specially made for the purpose and > tested > with solution A. Method for determining the comparative and the proof > tracking > indices of solid insulating materials under moist conditions. > > ...and reading the stuff on different pages it looks like it has > something to > do with surface insulation resistance and a materials ability to > prevent > arcing and sparking while carrying specified power loads...(I think) I > looked > for the test methods that were referenced above, and other test > standards > (IEC 1120 and ASTM D3638-93) that I read as referenced to determine a > materials CTI, to see if I could read and understand what the heck CTI > is all > about, but everybody wants money before they'll let you learn > anything. > > However, if you wanna go to http://www.cssinfo.com you'll find the > ASTM > D3638-93 standard there, and if you'll give them a credit card number > and pay > $21.95, you can download that standard online. It's precisely the > standard > test used to detremine Comparative Tracking Indexs with resins. > > Hope this helped a bit... > > -Steve Gregory- > > ################################################################ > TechNet E-Mail Forum 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's web site (http://www.ipc.org) "On-Line Services" > section for additional information. > For technical support contact Hugo Scaramuzza at [log in to unmask] or > 847-509-9700 ext.312 > ################################################################ ################################################################ TechNet E-Mail Forum 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's web site (http://www.ipc.org) "On-Line Services" section for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################