I know this has been discussed before but it's been a while. Potter and Brumfield (Siemens) makes a line of switch/breakers which are intended to be both a switch and a breaker in the same device, known as the W31 series. These work - but only for a while - they are not really a long-term service item. The trouble is that with every actuation there is a copper braid connection inside that will fatigue and eventually break. I had installed a few of these in my airplane, in less than "flight critical" points, knowing full well the history of the device and the possibility of eventual failure. Yesterday I had the first one quit on me, at 1506 hours and probably somewhere in the line of maybe 2500-3000 actuations.
The symptoms were that it would not turn on, would stay off, until I jiggled it on/off several times and then it would come on. I already had a spare on hand, replaced it immediately, and ordered another for a new spare. I also decided to pull it apart and look at the failure point internally to share here. It failed at the spot weld of the top braid in the picture. The wire braid there is very good - lots of small strands - but enough flexes over enough time will still cause them to break.
As always, your mileage may vary, etc etc - but if you put these in your plane, do NOT expect them to last forever, keep spares on hand, never for a "flight critical" load, and keep an eye on them.
The symptoms were that it would not turn on, would stay off, until I jiggled it on/off several times and then it would come on. I already had a spare on hand, replaced it immediately, and ordered another for a new spare. I also decided to pull it apart and look at the failure point internally to share here. It failed at the spot weld of the top braid in the picture. The wire braid there is very good - lots of small strands - but enough flexes over enough time will still cause them to break.
As always, your mileage may vary, etc etc - but if you put these in your plane, do NOT expect them to last forever, keep spares on hand, never for a "flight critical" load, and keep an eye on them.
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