The following is a copy of an article written by Steve McNeal from Soil Testing Engineers of Lake Charles, Louisiana. This article was recently published in the Louisiana Ground Water Association’s newsletter. We wish to thank both Mr. McNeal and the Louisiana Ground Water Association for allowing us to pass on such important information concerning the safety of our friends.
Overhead Power Lines
In 1990, a water well driller was working under a 12,000 volt overhead power line that was 36 feet above the ground. The job consisted of the repair of a submersible pump for a residence. With the mast of the drill rig raised, the driller removed the pipe from the well, which came into contact with the power line. The drill rig became energized, the driller provided a ground and was electrocuted.
Each year an average of 15 electrocutions occur through contact with overhead power lines with cranes or boomed vehicles. The drilling industry is not immune to this exposure: therefore, we should take notice of the findings of two government agencies.
The National Institute for Occupational Safety and Health (NIOSH) has found that electrocutions accounted for approximately 7% of all work related deaths during the period between 1980-1989. Similarly, in a separate study, the Occupational Safety and Health Administration (OSHA) found that 65% of the work related electrocutions occurred in the construction industry and nearly 30% of these electrocutions involved cranes.
Current OSHA regulations require drillers to take precautions when their drill rigs are operated near overhead power lines. These pre-cautions require drillers to assure that overhead power lines are de-energized or separated from the drill rig by implementing one or more of the following procedures.
- De-energize and visibly ground electrical distribution and transmission lines.
- Use independent insulated barriers to prevent physical contact with the power lines.
- Maintain a minimum clearance between energized power lines and the drill rig’s boom. (At least 10 feet plus 0.4 inches for each kilovolt above 50 kilovolts or maintain twice the length of the line insulator but never less than 10 feet.)
Where it is difficult for the driller to maintain clearance by visual means, someone should be designated to observe the clearance between the energized power lines and the drill rig.
The use of guards, insulating links, or proximity warn- ing devices will not alter the need to follow required precautions. These devices are not a substitute for de-energizing and grounding lines or maintaining safe clearances.
Consider the following methods of limiting your exposure to overhead power lines.
- Be cautious – operate the drill rig at a slower than normal rate in the vicinity of power lines.
- Exercise caution near long spans of overhead power lines, since wind can cause the power lines to sway laterally and reduce the clearance be- tween the drill rig and the power line.
- Mark the route the drill rigs must take in order to safely travel beneath power lines.
- Never move the drill rig with the mast raised.
- Keep all personnel well away from the drill rig whenever it is close to power lines.
- Prohibit persons from touching the drill rig or its components until a signal person indicates that it is safe to do so.
Notify Power Line Owners:
According to state laws, a one-call service should be utilized. Many states require that at least two days’ notice be provided before they will visit the site. If you have noticed that overhead power lines are in the vicinity of the site to be drilled, notify the power line owner to de-energize the line. If this is not possible, ask your client to relocate the drill site.
Evaluate Job Site:
Thoroughly evaluate job sites before beginning work to determine the safest area for material storage, the best placement for drill rigs during operation and the size and type of drill rigs to be used.
It is important to know the location and voltage of all overhead power lines at the job site before operating or working with any drill rig. If possible, meet with the client and the utility company at the job site to discuss the best method of protecting the drill crew.
In addition, do not operate the drill rig if a thunder and lightning storm is in the area. In this case lower the boom and wait for the storm to pass.
If contact occurs:
To protect against electrical shock injury in the event of contact between a drill rig’s mast and an energized line, consider the following:
- If you are able to understand what took place during the electric shock, you are most likely safe where you are and should stay put until you can assess the hazards.
- All personnel should keep away from the drill rig, augers, ropes and pipes, since the ground around the machine might be energized.
- The driller should not try to remove the drill rig from contact by moving it in the reverse direction from that which caused the contact. The driller should wait for help.
- If the drill rig is being driven and cannot be moved away from contact, the driller or operator should remain inside the cab of the truck until the lines have been de-energized.
If you are working in the vicinity of antennas, radar installations, or microwave transmitters, the mast of the drill rig can become thermally hot. Contact with the drill rig may cause burns. Therefore, be aware of these types of hazards, and take proper precautions to minimize your potential exposure.
Many times overhead power lines and antennas are overlooked. The result can be disastrous. Keep in mind how, with a little forethought, the dangers of working in the vicinity can be significantly reduced. If there is ever any question regarding such hazards, stop and determine the safest method before proceeding. Your life may depend on it.