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Ergonomics eTool: Solutions for Electrical Contractors
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Electrical employees may need to dig trenches and holes for underground electrical lines and fixtures. These digging tasks are very physically demanding and may have adverse effects on employees, especially when done for extended periods of time. Employee digging
 

Manual Digging and Trenching
Potential Hazards:

Awkward position while digging
Figure 1
Awkward position while digging.

Twisting the back while digging
Figure 2
Twisting the back while digging.

Using a trencher
Figure 3
Using a trencher.

One foot pivots while the whole body turns
Figure 4
One foot pivots while the
whole body turns.

Alternating hand placement on shovel between the left and right to shift stress placed on the body
Figure 5
Alternating hand placement
on shovel between the left
and right to shift stress
placed on the body.

Digging PPE
Figure 6
Digging PPE.
  • Lifting too much dirt at one time may cause muscle strain.


  • Digging for extended periods of time may lead to overexertion, causing fatigue and muscle pain.

  • Bending and twisting while manually digging (Figures 1 and 2) may cause low back pain and overexertion of the low back.
Possible Solutions:
  • Use a mechanical means of digging, such as a trencher (Figure 3) or backhoe.

  • Turn the whole body by moving the feet instead of twisting the torso (Figure 4).

  • Use long-handled tools to minimize torso bending.

  • Use the "right" shovel for the job.
    • Use round-bladed shovels for sand and dry earth.
    • Use square-bladed shovels for coarse-grained materials such as gravel or rocky soil from piles.
    • Use shovels with a rolled step for digging in hard earth, so that the pressure applied to the bottom of feet is spread over a wider area.
    • Use smaller shovel heads (trenching shovel) to minimize the weight of material lifted.
  • Break digging tasks into segments no longer than 15 minutes mixed with non-digging tasks, depending on environmental conditions and required digging effort.

  • Alternate shoveling between left and right sides of the body (Figure 5).

  • Reduce the throwing distance by placing wheelbarrows close to the digging area. Optimal throw distance is approximately 3 feet and should not exceed 4 feet.

  • Use proper personal protective equipment (PPE), including protective gloves and safety shoes with steel shanks (Figure 6).

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