Machines and equipment are isolated,where appropriate, fromt

You must always isolate an electrical machine from the mains supply before either cleaning it or carrying out any maintenance or repairs. There aretwo reasons for this:first,if you touch anelectrically live part you may get an electric shock; second,the machine may be accidentally started which could cause injury or damage.
With portable electrical appliances this simply means switching off and taking the plug out of the socket.
With fixed machinery,for instance a pillar drill, you will need to switch off the power supply at the isolator switch. This is usually found on the wall near the machine. Isolating this way is fine while cleaning the machine,but for carrying out maintenance or repair work it is advisable to remove the supply fuse from the isolator box. With the fuse removed the machine cannot be restarted if the isolator is accidentally turned on by a colleague who confuses the isolator for the one on an adjacent machine.