5. Portable power tools

Dangers from portable power tools arise from incorrect use and poor maintenance.

Great care must be taken when using portable power tools in the following locations:

• in damp or wet situations
  

• on steel structures and in other locations where good earth contact exists.

Effective earthing is of great importance as many hand tools are classed as single insulated appliances, and they rely on effective earthing and operation of the RCD, circuit breaker or fuse in the installation to provide protection should an electrical fault occur.

Electrical safety is provided by three main methods

1. Single insulation.
   
   
   • tools rely on effective earthing of the metal case to cause the fuse or circuit breaker to operate in the event of an electrical fault.
     
     
2. Double insulation.
   
   
   • this relies on two layers of insulation to provide the necessary protection.
     
     
3. All insulated.
   
   
   • tools are enclosed totally with no exposed metal parts.

6. Poor maintenance of power tools

Poor maintenance causes many unnecessary injuries in the workplace. Poor maintenance examples include:

• cracks in the casing of the power tool
  
• screws not holding the casing tightly
  
• brush caps not firmly in position
  
• sheathing of the flexible cord not held firmly in position at the power tool
  
• the flexible cord is in poor condition
  
• the plug top and extension socket are damaged
  
• the socket outlet is not the correct current rating or effectively earthed.
  

If there is any doubt about the safety of an electrical power tool, DO NOT USE IT! You should also tag the power tool and send the tool in for assessment and/or repair.

A regular maintenance program including insulation resistance and earth continuity test will reduce the possibility of accidents occurring.