There’s a problem with fuses. On the face of it, testing would seem to be a one-shot deal — exceed the rated current and see if it blows. But once you know the answer, the device is useless. If only ...

1. Most of us have ‘trip-switch’ fuses nowadays, instead of the old white fuse box. 2. Turn off your electricity at the mains before you do anything. You’ll see it in your fuse box – a larger switch ...