Platinum contacts

I work with copper, platinum, and silver wire. I hold up a piece of platinum wire above a BIC and it does not turn black with soot if held there. Your going to have to get that contact pretty hold to do this test. May affect other things.

greg

:or are they? how do you tell ? :Raised pips spot-welded? on otherwise silver plated rockers in switch rated :15 amp , 250V. :If platinum, are they wholly platinum or somehow coated on a more base metal :for the main body of the pip.

Going back into the dim dark recesses of my memory (with a little refreshing thrown in) I recall the use of platinum relay contacts was usually only specified where high reliability and/or currents and the presence of arcing was expected. It is rare to find pure platinum contacts and they usually have some added element to harden them and make them more resistant to tarnishing, arc formation and wear. Materials such as iridium, ruthenium, nickel, molybdenum or osmium are used.

How do you tell whether they are platinum contacts or not? I don't know. It may depend on the manufacturer and you have to take their word for it. On 3000 type relays used in telephony platinum contacts were marked with a V notch at the end of the spring.