Overhead power lines | Electrical overhead line, HV Cables, HV Transformers

                                    OVERHEAD POWER LINES

WORK ON HV CABLES, WORK ON HV TRANSFORMERS AND WORK ON LOW VOLTAGE

Overhead power live lines

OVERHEAD LINES

WORK ON HV CABLES, WORK ON HV TRANSFORMERS, AND WORK ON LOW VOLTAGE

WORKING NEAR ELECTRICAL LINES OR EQUIPMENT:

1.       Electrical Lines are live energized.

2.       Electrical Lines are operating at high voltage.

3.       Electrical Overhead Powerline Policy.

4.       Electrical technicians or other Personnel shall not place themselves close to electrical overhead lines.

5.       Ensure distance is 3m or 10 ft. for systems up to 50 kV and is increased 100mm or 4 inches every 10 kV above 50 kV electrical cables.

6.       Electrical technicians or other Personnel be informed of the hazards and precautions when working near electrical overhead lines.

7.       Ensure warning signs shall be displayed on cranes and similar equipment regarding the minimum clearance of 3m or 10 ft. of electrical clearance.

8.       An Electrical technician shall be designated when equipment is working near overhead lines and to direct the operator accordingly.

9.       Ensure warning cones shall be used as visible indicators of a 3m or 10 ft. safety zone when working near electrical overhead power lines.

LOOK UP AND LIVE OVERHEAD POWER LINES

When the boom lift, man lift, or forklift is in its stowed or cradled position the flag shall be located on the load hook before operating the boom lift, and the boom lift operator of the equipment shall access the work area to determine the location of all overhead lines and communicate the same to all crews on site. After this is completed, the operator shall remove the flag from the load hook and transfer the flag to the steering wheel of the vehicle of the boom lift. After the flag is placed on the steering wheel, the operator may begin to operate the equipment of the boom lift.

Ensure after completing the activity and returning the equipment to its stowed or cradled position, the operator shall return the flag to the load hook.

HIGH-RISK TASKS

HEAVY MOBILE EQUIPMENT

Before the start of mobile equipment each workday and where practical, a high visibility marker, orange safety cones, or other devices shall be temporarily installed to mark overhead wires. When working in proximity to electrical overhead lines, a spotter shall be positioned in a conspicuous location to direct movement and observe for contact with the electrical overhead power lines. The equipment operator and all other personnel working on the job location shall be alert for electrical overhead power lines.

WORKING ON HIGH VOLTAGE

GENERAL

Electrical high voltage repairs, maintenance, alterations, cleaning, or testing on HV apparatus:

·       Provided a valid PTW as per standard.

·       Ensure switched off from all points of supply of electrical source.

·       Ensure the approved voltage testing device suitable for the rated voltage of the circuit. The testing of the electrical device shall be checked for correct operation following the manufacturer’s instructions, immediately before and after use.

·       Ensure Isolated and all steps are taken to secure with Isolation Padlocks from all points of supply, including where practicable voltage and auxiliary transformers, common neutral electrical equipment, and any other source from which the apparatus and conductors may become LIVE and caution notices are attached at all points of isolation of electrical points.

·       Electrically connected to earthling at all points of disconnection from high voltage supplies to such apparatus or between such points and the points of work or testing in line of electrical. Screened where necessary and danger notices attached to live equipment close to the point of work.

WORK ON HV CABLES

Ensure no one person touches or cuts into the insulation which covers the conductor unless the conductor is Dead, Isolated, and Earthed of electrical.

Ensure before issuing the PTW permit to work, identify the cable to be worked on at the point of work, and prove it dead by approved spiking equipment or other approved.

WORK ON HV TRANSFORMERS

1.       Where auxiliary or voltage transformers cannot be isolated from the HV high voltage conductors, the LV light vehicles' fuses or links are withdrawn and kept in a safe place during the progress of the work.

2.       Work is to be carried out on an HV/LV electrical transformer, ensure that the LV light voltage windings are isolated either by the opening of a switch or withdrawal of fuses or links so that any possible.

3.       Prevented during the progress of the work. Attach caution notices at the points of electrical isolation.

4.       PTW permit to work identify at the point of work, the transformer to be worked on.

WORK ON HV SWITCHGEAR

Discharge its conductors to Earth

1.       The section of the bus bars on which work is to be carried out is made.

2.       Dead and isolated from all points of supply from which it can be made Live electrical.

3.       Isolating arrangements are secured with safety padlocks and where practicable, the shutters of live electrical spouts are locked shut.

4.       Safety caution notices at all points where the bus bars can be made electrical Live.

5.       Safety danger notices, where applicable, on or adjacent to apparatus containing live conductors at the limits of the bus bar on which work is to be carried out.

6.       Electrical voltage testing device that the bus bars are dead, checking the voltage testing device before and after use.

7.       Earthling the bus bar at the point of testing and where practicable lock the circuit main earth in position. Attach an earthed notice to the circuit breaker or earthling device.

8.       Ensure test with an approved voltage testing device on every spout where work is to be carried out, checking the voltage testing device before and after use of the device.

9.       All remote control and automatic features are made so that they cannot be operated and, where practicable, secure with safety padlocks and caution notices.

10.   Work on HV high voltage static capacitors

11.   Ensure approved capacitor earthling devices to the capacitor frames.

12.   Ensure approved capacitor earthling devices to the common connection of each group of capacitors.

WORKING ON LOW VOLTAGE

GENERAL

No one electrical technician/  person shall undertake any repairs, maintenance, alterations, cleaning, or testing on HV apparatus until such parts of that apparatus are:

Switched off from all possible points of electrical supply and made dead

Ensure Isolated from all possible points of supply. The isolation shall normally be carried out by opening circuit breakers/switches and by removing fuses or links.

Ensure screened were necessary to prevent danger, and danger notices are attached to draw attention to living apparatus near the point of work electrical.

Approved voltage testing device suitable for the rated voltage of the circuit. The electrical voltage testing device shall be checked before and after use to check it is working correctly.