When you use small portable electricity meters, at some point you will accidentally touch something that has too much current for your meter. So it will stop working. The solution is one of those little 1/2 volt fuses. Buying 100 of these little things is too much. But that's not the same as going to the Radio Shack to get it. With one from RS you can get 100+ from AMAZON if you have the time and fuel. I received them from AMAZON within two days.