When defusing a bomb, why can’t you just cut all wires at once?

Question

When defusing a bomb, why can’t you just cut all wires at once?

In: 3949

Answer 1

We have an emergency button at work. If it’s pressed it calls the police and sends out a silent lockdown alert to everyone’s E-mail.

You can’t cut the wire to the button without setting off the alert. It has a small current going through it and a resistance that is measured. If the resistance goes up or down the alert is sent out and the police are called.

We discovered this when we moved the desk that the button is attached to and unplugged it. Oops.