Digging a small trench in the grassy landscaping for shallow burial of a cable or raceway poses a few hazards — for example stepping into the trench and twisting your ankle. But working in an excavation means a much higher hazard level.
As opposed to that trench, an excavation:
- Is wider, often wide enough for you to lower yourself into.
- Is deeper, perhaps deeper than you are tall.
- May be located near or in traffic areas. That could be with your torso exposed or not exposed while you are in the excavated space.
- May be long enough to require a crossover means.
A key point to remember is it might not be your excavation. It’s normal for an electrician to be working in some other company’s excavation, one that was made with heavy equipment. That doesn’t mean you trust them to get everything right. They may not have installed the proper shoring, barriers, or egress means. And there may be other mistakes that can endanger you.
Here’s a rough sequence of steps to protect yourself.
- Assess whether you would be breathing air within the excavated space. If so, a confined entry permit is required. Don’t be fooled by the fact the space is “open” at the top. Heavier-than-air gases can easily kill you (even in wide open areas) by blanketing depressions and trenches.
- Assess the completed excavation for mechanical integrity. Do the sides slope at the correct angle for the soil type? Is it properly shored up?
- Eyeball any nearby loads (e.g., vehicles, excavated soil, equipment) that can press on the edges of the excavation. Ask those to be moved back at least 2 feet from the edge. Where practical, move them at least as far from the edge as the hole is deep.
- If the trench is deeper than four feet, is there a safe means of egress and ingress? For a long trench, is there such a means every 25 feet or less?
- Is there an attendant, and is this person both qualified and equipped for the task? Before entering the trench, clearly communicate with the attendant(s) what you will be doing and how long you expect to be doing it. It’s not enough to ensure whoever is doing that job doesn’t just walk off and leave you in the trench. Discuss the responsibilities of the attendant, and confirm this person understands them and is capable of carrying them out.
- Is there a gas line within 100 ft? If so, testing for an explosive atmosphere is required.
- Where are the first aid kit, fire suppression equipment (e.g., portable extinguisher), and any rescue equipment that might be needed?
- Do barricades of any sort need to be present? If so, ensure they are. Same for any warning signs or warning lights.
- Once you enter the trench, test the egress by exiting. If it crumbles or has any other issues, get those addressed.
- While you’re working pause periodically to check the walls and shoring for any signs of movement. If you spot those, exit the trench and report the problem.
