No, not if they are careful and follow the simple rules to securely isolate electrical equipment, and check it is dead before they start work. If you received an electric shock but were not injured then you were lucky. Next time a slight change in events may lead to a very different result. No-one is immune to injury from electricity.For more information, see:Electrical injuriesElectrical safety and you Electrical safety and you (Welsh version)Electricity at work: Safe working practices