While this is a demonstration of a short circuit condition.  There are three  real  important things to remember...

Important To Remember -

1)  Make sure you have the proper clothing, eye protection, gloves, and the proper test equipment.

2)  Always meg-ohm your load while the power is off to be sure there are no short circuits on the load side of your circuit protection.

3)  Never stand directly in front of a disconnect or panel when closing (energizing) the switch.

View This short clip to see what can happen if the load is shorted when you close the switch.