Why does a Circuit Breaker trip when a lamp fails?
This is a very common problem, and nothing to worry about. You may even find that a couple will go in a multi-light fitting in the same week. This because if you bought all the lamps together when it was new, they will tend to fail fairly close to the expected 1000 hour life, since modern manufacturing techniques produce lamps with the same internal characteristics time after time. The reasons for the CB tripping out, are due to the fact that when the filament fails, for a very brief milli-second or so, it draws a plasma like arc (spark), in the vacuum of the glass, as the 2 ends of the filaments part. Because this is a high current, relative to the CB tripping current, it will trip as it is designed to do that. There is supposed to be a little glass fusible element one one of the lead-out wires in the neck of the bulb, but I have never known these blow fast enough before the CB detects the high current. Sometimes the wires vapourise during this high current state, and I have known the
