>One thing to remember is that an amp is an amp regardless of the overall >circuit voltage. If a switch is going to get hot at 1 amp in a 125V AC >circuit it will also get hot at 1 amp in a 12V DC circuit.
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ It would appear that several posters missed the point on why a switch will handle less DCV than ACV. When a switch contact closes the current will start flowing before the contact closes. It will arc across the gap when conditions are right. The same happens when the contact opens. The current continues to flow in the form of an arc as the contacts open until it can no longer jump the gap. The DCV will sustain the arc longer than ACV and thus "burn", "pit" and otherwise destroy the contact much faster. Some better quality switches will use gold plated contacts and such things as the contacts making a swipping action on open and close to help clean the contacts. I randomly opened switch bodies to check the contacts of a failed switch in my 33 years with Xerox and it is amazing what you will see and the switch only failing intermittently. One suggestion for those high current circuits where you are concerned with switch failure is to use a high amp rated relay to carry the circuit current and the switch to energize the relay where it only carries a very low coil current. You can get a good quality Bosch 30 amp (small body), multi-contact relay for under $5 with a little searching. I wouldn't trust the "made in Mexico" relays from Auto Zone or similar suppliers. This is not a dig at our neighbors south of the border but applies to poor quality components regardless of where they are made. Many will say that you double the number of components that could fail but I'm convinced you will be reducing the odds that they will do so. Just my non scientific gut feel. I've not seen the book several poster have mentioned but I've heard from other sources that it is very good. I should have put it on my Christmas list. Larry Flesner Carterville, Illinois
