Electrical safety on construction sites

May 20th, 2011

Most deficiencies in electrical safety occur on construction sites in relation to overhead power lines, faulty or damaged portable tools and electrical leads, and underground cables. Ensuring your employees are able to identify, avoid or deal with potential electrical dangers is paramount to the overall safety and productivity of the worksite.

Overhead Power lines
If the worksite is near overhead electrical power lines, work must not commence until ‘permission’ from the electricity company has been granted or they have developed safe systems of work using industry specific No Go Zone safety procedures.

If possible, work should be repositioned away from the overhead electrical assets to avoid encroaching on a No Go Zone. In some case, the overhead cables may be relocated, or smaller earthmoving equipment can be used as a substitute.

If the problem is recurring, the modification of earthmoving equipment design may be considered. Alternatively, overhead cables can sometimes be temporarily shut down or isolated by erecting temporary physical height barriers to limit higher loads from passing under an overhead cable.

Ultimately, developing work procedures and systems involving adequate training, skill and supervision can reduce risk. Aspects of the workplace environment may be modified to increase safety, such as signage and marking of designated restricted movement areas for trucks and other equipment delivering or working on site.

Power tools and electrical leads
When workers use portable power tools and electrical leads that are electrically faulty or damaged they may suffer electrical shock, which could result in death, heart problems, internal organ damage or burns. To reduce risk of injury or death, electrical leads and power tools should be visually inspected prior to use, and avoided if equipment appears to have been modified or damaged. Tools should only be plugged into socket outlets that are protected by a residual current device (RCD) or a portable RCD is used.

Workers should ensure power circuits are protected by the appropriate rated fuse or circuit breaker to prevent overloading and potential overheating. Electrical leads should be arranged so they do not run across the floor or ground, through doorways and over sharp edges. Where the lead arrangement is dangerous, lead stands or insulated cable hangers should be used to keep leads off the ground. Leads and tools should never be used in damp conditions unless they are specially designed for use in those conditions.

Underground Electrical Cables
Underground electrical cables can be damaged by earth moving equipment, mobile cranes or heavy vehicles on construction sites. Damage to underground electrical cables can lead to electrocution or injury to plant operators and people nearby. Disruption of the power supply can also have health and safety and other consequences.

Ensure workers are aware of any underground cables by telephoning ‘Dial Before You Dig’. It is important to call at least two working days prior to commencing any work that may be located near underground electrical cables.

Have current site drawings showing any cables and services, on site to be referred to prior to digging. Also use the drawings to mark the route of the cable on the ground and erect warning signs to inform all on-site personnel of the location of any cables. Even if earthworks will not directly contact the cables, ensure they do not weaken the soil to the extent that cables may be damaged.