Working Around Overhead Power Lines

Job Description

This guideline describes safe methods of working around overhead power lines.

Hazard Identification

Personal Injury
• Electrical contact – death, burns, disability, dismemberment.

Vehicle/Equipment
• Overhead lines – equipment damage, fire, explosion.

Environmental
• Weather conditions – wet, windy, temperature extremes.

Practices

1. Pre-Job Planning
1.1 Before work begins, all power line locations are to be identified. The Contractor is responsible to contact the power company, provide and install warning devices, and communicate potential hazards to the workers.
1.2 All workers who operate machinery or equipment that could come in contact with power lines should look up and check for overhead power lines before beginning work.
1.3 Height of power lines should be obtained from the power company or surveyors.
1.4 Erect proper warning signs before work begins under or near the power line.
1.5 Maximum height of truck boxes shall be displayed on the front left corner of the truck box.

2. Limits of Approach
2.1 When operating machinery or equipment in close proximity to power lines, always maintain the limits of approach: 3–6 metres, depending on the voltage. For safe working distances, see the table below.
2.2 When excavating around a power pole, stay at least 2 metres from the pole at ground level and angle the excavation away from the pole as you go down.
2.3 Following are the minimum clearances for known power line voltages, from Saskatchewan OHS Regulations (1996) Appendix Table 22: These clearances are measured as the radius around the conductor.
Risk Factor Column 1 Column 2 Column 3
Voltage Phase to Phase Voltage to Ground Non-Electrical Workers, Material and Equipment Qualified Electrical Workers Vehicles and Load Traveling – movement down roadway where work tasks are not being performed
kV kV Metres Metres Metres
230 133 6.1 1.4 1.83
138 79.8 4.6 1 1.22
72 41.6 4.6 0.6 0.8
25 14.4 3 0.3 0.6
15 8.6 3 0.3 0.6
4.16 2.4 3 0.15 0.6

2.3.1 OHS Regulation 465 (2):  …no worker works, no material is piled, stored or handled, no scaffold is erected or dismantled and no equipment or powered mobile equipment is used or operated within the minimum distance set out in Column 1 of Table 22 above.
2.3.2 OHS Regulation 465 (6):  …no part of a vehicle is operated on a public road, highway, street, lane or alley within the minimum distance set out in Column 3 of Table 22 above, and that no part of a vehicle’s load comes within the minimum distance.
3. Power Line Identification

Following are guidelines for pole and kV identification.
One pole – 14.4 kV    One pole – 120 / 240 kV One Pole – 25 kV
One pole – 72 kV  Steel Tower – 130 – 230 kV 2 Poles 72 – 138 – 230 kV

4. Operating Practices
4.1 No person shall approach or operate heavy equipment within 6 m of a power line of unknown voltage unless directed by a competent utility employee.
4.2 If the work area has the potential for equipment to come in contact with power lines because it would not be possible to keep this distance, the power company can be contacted to de-energize or reroute the circuit or provide guarding.  Do not proceed until the power company has given written assurance defining proper safeguards.
4.3 If the required distance cannot be maintained, then alternative plans for dumping material, such as dumping before and after the power line, must be developed and implemented. If the truck dumps directly under the line, they are not to raise their boxes as high as normal and a Spotter must be used.
4.4 Assign a worker to act as a Spotter to ensure that the required clearance is maintained. The Spotter shall monitor equipment and material movement and give an instant STOP signal to the equipment operator when the equipment or load is too close to the electrical conductor.
4.5 The Spotter must abide by the following:
4.5.1 Review and know the limits of approach outlined above.
4.5.2 Review and know the prearranged signals with equipment operators and truck drivers.
4.5.3 Review and know the heights of truck boxes when fully raised.
4.5.4 Review and know the heights of overhead power lines on the project.
4.5.5 Be positioned at limits of approach from the truck and in clear view of driver.
4.5.6 If available, use radio contact with equipment operators.
4.6 When lifts of material are placed underneath power lines this reduces the clearance. A review of the clearances after each lift should take place.
4.7 Operate the equipment at a slower-than-normal rate in the vicinity of power lines.
4.8 Never park equipment in the vicinity of power lines.

5. Ground Worker Positioning:
5.1 All ground workers and Spotters must stay at least 10 metres away from equipment operating in the vicinity of power lines because if it contacts an energized line the electricity will go to ground.

6. In The Case Of Power Line Contact:
6.1 The Operator should STAY IN the cab or on the equipment and remain calm.
6.1.1 If you have to leave the equipment because of an emergency, jump clear of the equipment landing with feet together in upright position, and SHUFFLE OR HOP with feet together, DON’T STEP.
6.2 This is a reportable Dangerous Occurrence – Saskatchewan Occupational Health and Safety Regulations (1996), section 9.  Contact the power company, project supervisor and manager immediately, and determine who will contact Department of Labour.
6.3 The following applies to ground workers.
6.3.1 When there are downed lines remember that there may be dangers you can’t see in the immediate area. Your job is to stay away and secure the area to keep others safely away.
6.3.2 If you are on energized ground and need to move away, you can avoid electric shock or electrocution by making sure there is no space between your feet. Shuffle your feet while moving out of the energized area. When shuffling, keep your feet touching. Do Not Take Steps.
6.3.3 10 Metres To Safety.  Stay back at least 10 metres from any contacted equipment or downed power line.
6.3.3.1 Depending on voltage of downed power line, this distance may increase up to 32 metres.
6.3.4 Contact the power company, project supervisor and manager immediately and be sure to specifically mention the downed wire situation.

Personal Protective Equipment

• As required by Contractor Safety Policy.
Tools / Equipment

• As required by Contractor Safety Policy.
Related Safe Operating Guidelines

List relevant Contractor S.O.G.s that are available, such as:

• Backing Up
• Working Around Ground Workers
• Pilot Vehicle Operation
• Sweeping Operation