Question

In case of a fire, before the firemen use the water hoses, they shut off the
main electrical supply for the area. Explain why they do this.​

Answer 1

Impure water which is generally used by fire men's is a good conductor of electricity and if they used that water on any electrical appliance in the house it would result in a short circuit and people might get shocked.

So electricity is cut off to prevent it or CO2 fire extinguishers are used which does not conduct electricity.

Hope it helps....

Answer 2

Answer:

In case of a fire, before the firemen use the water hoses, they shut off the main electrical supply for the area because water sprayed from the hose might conduct electricity which may come in contact with the electrical appliances which increases the chance of electricity passing through wire. This may hurt fire man.