Workplace precautions are designed to reduce identified risks to an acceptable level A wide range of workplace precautions are available, some more effective than others.  Typical workplace precautions include machinery guards, personal protective equipment (PPE) and safe systems of work. The most appropriate workplace precautions for any activity are decided by applying the following priorities:  
straight forward health and safty advice 
General safety
Elimination Substitution Engineering Controls Administrative Controls PPE Least effective Most effective
In many instances, effective control of significant risks will only be achieved by implementing a proper method statement and/or a permit to work system that is appropriate to the task. Where a permit system is used, it must be followed.
if possible avoiding the risk altogether where possible combating the risks at source giving priority to measures that protect the whole workplace wherever possible, adapt the work to the individual taking advantage of technological & technical progress using personal protective equipment (PPE) to minimising risk is considered a last resort