Interesting! I did not realise they were so slow to blow. But I also had a feeling that they may have also been intended as a poor-man's RCD back in the day:

Interesting! I did not realise they were so slow to blow. But I also had a feeling that they may have also been intended as a poor-man's RCD back in the day: Your washing machine shakes the live loose and it touches the (thankfully earthed) metal case. Then you have a dead short across the fuse which should hopefully be enough to blow it pretty quickly..