Circuit Breakers

15 Amp Single Pole Type QT Tandem NCL-Circuit Breaker $27.96

15 Amp Tandem Single Pole Type QT Circuit Breaker $10.72

I needed to squeeze one more circuit into the electrical panel at the new house. Two half size breakers would do the trick, so I stopped by Home Depot yesterday and picked up a couple. Of course there is more than one kind and I picked up the wrong ones. Some panels have clips that will accommodate half-size breakers, but others don't, which is the kind I have. In this case, you can still use half size breakers, but as this panel only has a single vertical blade to connect to the breaker, the two half size breakers need to be combined in one package. One breaker contacts one side of the blade and the other breaker contacts the other. Further, the blades in some panels are shaped to prevent some of these tandem breakers from being plugged in. Tandem breakers designed to work with (or against) this feature cost $10. Breakers that ignore this special feature are $28. Looking at them at the store I couldn't find any difference. Bought one of each because they only had one of the cheap ones. Took them back to house and found that they both plugged into the breaker panel fine, but then I found that one of the breakers in the expensive one was broken, so I had to go back to the store and exchange it. Geez, what a lot of hassle. Could have saved myself a lot of trouble if I hadn't just run off half cocked, but where's the fun in that?

After I found out about the difference between these two, I examined them again and I did find that the clip looks slightly different, but the difference doesn't really give you any clue as to what's going on.

If you are going to worry that adding this one 15 amp circuit is going to overload this panel, don't. The total capacity of all the installed breakers is over 800 amps and the panel's capacity is only 200 amps. Some of the circuits are for very heavy loads that only get used intermittently, like the hot tub, sauna, clothes dryer and oven. You just need to be aware of the panel's limitations. Turning everything on at once will surely trip the big 200 amp breaker.