1 You don't have to/mustn't use electrical appliances around water. 2 You should/mustn't unplug an appliance from the socket when you are not using it.
3 You shouldn't/have to plug a lot of appliances into one socket.
4 You must/don't have to change a light buld if it's still working.
5 You have to/mustn't use a safety cover if you have young children.
6 You must/shouldn't always be careful when using electrical appliances.​