Re: Not just business
You are wrong, it is explosive - I have been in the factory, I have seen the "munition store" and the certificates for explosive handling.
The way it works is that there is a resistance wire in parallel with the fuse, embedded in the explosive. When the main element blows, the current tries to pass through the resistance wire, causing rapid melting, arcing and detonation.
The reason it is needed is that in a 3 phase star installation, if one phase is lost the difference current now travels down the neutral wire, which isn't designed to take it. So loss of one phase causes the equipment to open all three phases to prevent this happening.
Many years ago I worked briefly for a company that had some quite large conveyor furnaces that had been wired by a less than competent electrician. Over a weekend one phase was lost. Fortunately there was no fire, but the entire feeder cables had to be replaced due to the overheating caused by the neutral current.