SDS-PAGE overheating and long running time - (Sep/23/2008 )

For the past month or so, everytime our lab runs SDS-PAGE gels they overheat and take a very long time to run (over an hour to run 2 10% gels) . We used to be able to run them at 200 V but now we are running them at about 135V and they are still overheating. The watts increase very fast. Each time we run the gel at first it is fine and the watts are not increasing and then once it gets to the middle/end of gel the watts increase from about 15 to 22. We have changed the buffer several times and made new 10x stock and then diluted to 1x. Could the problem be the gel? We make our gels fresh. We have just prepared new acrylamide could that be the problem? Should we keep our buffers at 4 degrees? Any suggestions would be greatly appreciated! Thanks!

Have you tried different power supply?

keep buffer (1x) cold and change at half time the running. When running the gel do in the refrigerator or place the chamber in ice (this a little bit hassle). Check for leaks because tht will cause the power supply to stop. SDS gels take more time to run than agarose so if running two at the same time it will take a lot more than 1 hour.