Given that the need of industries and other facilities (such as hospitals and the like) for a reliable and uninterrupted supply of electric power is steadily increasing, and that a power outage may cause financial losses and hazards to life, alterations and modifications must of necessity also be carried out on live lines and equipment. The purpose of drawing up this Regulation is to set out the rules and conditions which, if followed, will make it possible to carry out operations relating to the alteration, conversion, modification and repair of live lines and equipment while ensuring the safety of personnel.
General Provisions
Carrying out any conversion, modification or alteration on live lines and equipment shall be permitted only when those lines and equipment are suitable for the work to be performed in the live condition.
Making changes to existing lines and equipment to bring them into conformity with the provisions of this Regulation for the purpose of live-line work shall be required only where the work referred to in Article 1, other than essential repairs, is determined to be necessary.
The provisions set out in this Regulation constitute the minimum conditions required to ensure occupational protection and safety. It may therefore be necessary for workers to observe other rules, in addition to those set out in this Regulation (provided they do not conflict with it), to ensure greater safety.
Conducting Preliminary Inspections and Tests, and Determining Existing Conditions
Before carrying out any kind of work, the existing conditions shall be determined by means of the necessary inspections or tests.
The determination of existing conditions referred to above includes establishing the characteristics of the live lines and equipment, the condition of the poles, their location, the circuits and equipment associated with the power lines, and all communication services, together with other relevant factors.
Power lines and equipment shall be deemed to be live until they are found to be de-energized by means of the necessary tests or by another suitable method.
Before carrying out any work on lines and equipment, or in their vicinity, the operating voltage shall be determined.
Permissible Clearances
No person shall be permitted to make contact with live parts without the use of suitable insulating tools, or to approach live parts closer than the distance specified in Table 1, except in one of the following cases: (a) persons are insulated from, or protected against, the live parts;
Note – Gloves, sleeved gloves, or other protective equipment suitable for the voltage concerned shall be accepted as a means of insulation.
(b) the live part is insulated or protected from persons or from any other conductive object whose voltage differs from the voltage of the live part in question; (c) persons, such as those prepared to work using the bare-hand method, are insulated from, separated from, or protected from other conductive objects.
The minimum permissible working clearances, and the minimum permissible working clearances when using an insulated jumper, specified in Table 1 shall be strictly observed. The minimum working clearance with an insulated jumper is the distance maintained by a person while holding the jumper, or similar insulating equipment, and performing work on a live line or equipment with it.
Conductor support and holding tools, such as clamp-type jumpers, and the tensioning and support of tension (strain) insulators, may be used only on condition that the permissible distance is at least equal to the length of the insulator string, or the lengths given in Table 1 for the relevant working voltages.
Table 1 – Minimum Permissible Clearances for Alternating Current
| Voltage between phases (kV) | Minimum permissible working clearance, or clearance with an insulated jumper (m) |
|---|---|
| 11 and below | 0.6 |
| Above 11 up to 33 | 0.7 |
| 63 | 0.9 |
| 132 | 1.0 |
| 230 | 1.5 |
| 400 | 3.5 * |
* This clearance may be reduced, provided that the distance selected is not less than the clearance from the live parts of the line to earthed parts.
Emergency Measures and First Aid
The employer shall provide the necessary training for its workers in the following areas, or shall ensure that they have sufficient knowledge and competence in these matters: (a) procedures relating to emergency situations; (b) the principles of first aid and the rescue of a person suffering an electric shock.
Night Work
When working at night, floodlights or portable lamps, as appropriate, shall be made ready and provided to workers for carrying out the work.
Work Near or Over Water
When working over or near water, and where there is a risk of drowning, protective measures shall be taken to prevent drowning.
Hydraulic Equipment Fluids
All fluids used in the insulated sections of aerial-lift trucks or hydraulic equipment employed on or near live lines or equipment shall be of an insulating type.
Tools and Safety Equipment
Safety Equipment
Rubber safety equipment shall conform to the standard, and the following points shall be observed in respect of it: (a) rubber safety equipment shall be inspected before and after use; (b) rubber gloves shall be tested with compressed air before and after use to ensure that they are sound; (c) rubber table [bench] safety equipment shall be electrically and mechanically equivalent to, or better than, comparable rubber equipment.
Protective helmets shall conform to the standard and shall be used by workers when working at sites where there is a risk of falling objects, electric shock, or burns.
Personal Climbing Equipment
When working atop poles, towers, and other structures, safety belts fitted with a protective rope and strap shall be used, unless the use of a safety belt would create a greater risk to the safety of persons in terms of falling objects, electric shock, or burns.
Safety belts and protective ropes shall conform to the standard. A safety belt may also be used to hold work tools, in addition to its primary purpose of protecting the worker; belts shall be free of any additional metal rings or hooks other than those specified in the standard.
Safety belts and ropes shall be inspected before and after use to ensure that they are free of defects.
Safety ropes shall not be subjected to shock loading and shall be used only for emergency rescue operations, such as lowering persons; such ropes shall be at least 17 millimetres in diameter and shall be made of 3 or 4 strands of grade-one hemp, or an equivalent material in terms of durability and strength (1770 newtons or 1300 kilograms-force).
Defective ropes shall be replaced.
Ladders
Portable metal ladders, or ladders made of other conductive material, shall not be used in the vicinity of live lines or equipment, except for specific work, such as work in high-voltage substations, where insulating ladders may pose a greater hazard than conductive ladders.
Conductive ladders shall be clearly marked, and all necessary precautions shall be taken when they are used for such specific purposes.
Hook ladders and similar equipment used in the operation of facilities shall be secured in a reliable manner to prevent their accidental displacement.
Tools for Work on Live Lines
For work on live lines, only jumpers bearing the manufacturer's certificate of withstand under the following conditions shall be used: (a) 100000 volts per 0.3 metre of length for a duration of 5 minutes, in the case of tools made of fibreglass; or (b) 75000 volts per 0.3 metre of length for a duration of 3 minutes, in the case of tools made of wood.
Note – Jumpers lacking a manufacturer's certificate, whose characteristics have been established by testing in accordance with the above, may also be used.
All live-line equipment shall be inspected daily before use. Immediately before using a tool, it shall be cleaned with a cloth or similar material, and if any defect is observed, the tool shall be withdrawn from service.
Measuring Rods and Tapes
Metal measuring rods or tapes, or those containing conductive fibres, shall not be used while working on live lines or in their vicinity.
Hand Tools
All hydraulic tools used on live lines or equipment, or in their vicinity, shall be fitted with hoses made of insulating material, and the pressure rating of such hoses shall be sufficient for the normal operation of the equipment.
The special regulations applicable to this type of equipment shall also be observed.
All pneumatic tools used on live lines and equipment, or in their vicinity, shall: (a) be fitted with hoses made of insulating material, the pressure rating of which shall be sufficient for the normal operation of the equipment; and (b) be equipped with a moisture-collecting device on the compressor.
Mechanical Equipment
General
Before using mechanical equipment, it is necessary to inspect it to ensure that it is in proper working order.
At the start of each work shift, the operation of the brakes and operating systems shall be tested to ensure that the equipment is in a suitable condition for work.
No worker shall be permitted to operate a motor vehicle whose rear view is obstructed, unless: (a) the vehicle is equipped with an audible reversing alarm whose sound is audible above the surrounding ambient noise; or (b) the vehicle is reversed only under the guidance of another person.
Aerial-Lift Boom
When working near live lines or equipment, vehicles equipped with an aerial-lift boom shall either be electrically earthed, or a barrier or obstruction shall be erected around them to prevent contact by persons (in which case the vehicle shall be deemed to be live), or the vehicle shall be insulated from earth for the purpose of the intended work.
If the person or persons in the bucket are in a position where a live line or live equipment is within their reach and they are not protected by insulating equipment, no materials or other equipment shall be passed between the pole, tower, or similar structure and the boom bucket.
Other regulations relating to aerial-lift booms shall also be observed.
Boom Trucks, Cranes, and Other Lifting Equipment
Except for equipment and tools specifically intended for work on live lines and equipment, other equipment and tools shall not approach live parts closer than the values given in Table 1 of Chapter One of these regulations, except in the following cases: (a) An insulating barrier is installed between the live part and the mechanical equipment. (b) The mechanical equipment is earthed; or (c) The mechanical equipment is insulated; or (d) The mechanical equipment is deemed to be live, in which case the relevant safety precautions shall be mandatory.
Other regulations relating to boom trucks, cranes, and other lifting equipment shall also be observed.
Earthing of Equipment and Lines for the Protection of Personnel
Installing the Earth Connection
When making an earth connection (for work on both live and de-energized lines), the end connected to earth shall be attached first, after which the other end shall be connected or disconnected using insulating equipment or other suitable means.
When removing an earth connection, the earthing device shall first be disconnected from the lines or equipment using insulating tools or other suitable means.
Earth Electrode
To remove hazards to workers and to ensure the rapid operation of protective devices, the earth resistance of earth electrodes, when used, shall be sufficiently low.
Earthing via the Tower
Earthing via towers shall be carried out using a tower-specific clamp capable of carrying the anticipated fault currents.
Earthing Conductor
An earthing conductor connected to the tower earth or to a buried or driven earth electrode shall be capable of carrying the anticipated fault currents, and its minimum conductivity shall be equivalent to that of a copper conductor with a cross-section of 35 square millimetres.
Overhead Lines
General
Before climbing poles, ladders, scaffolds, and other similar elevated structures, the necessary examination shall be carried out to determine their strength against the additional or leverage forces that will be applied to them.
In cases where climbing poles or similar structures may not be safe, before proceeding, they shall be made safe by guying, bracing, or other acceptable methods.
Before installing or removing a conductor or cable, the forces that will subsequently be applied to poles or similar structures shall be taken into account, and the necessary measures shall be taken to prevent the failure of load-bearing members or objects. (a) When planting, transporting, or removing poles from the ground near live lines or equipment with the aid of a boom crane, a tripod, or other mechanical means, the necessary precautions shall be taken to prevent these means from contacting the lines or equipment, except in cases where the work on the live lines is carried out using the bare-hand method or where barriers or other protective equipment are used. (b) Equipment and machinery used near live lines or equipment shall conform to the provisions of Chapter Three. (c) Except where protective equipment appropriate to the operating voltage is used, workers on the ground shall refrain from contact with machinery and equipment located near live lines or equipment. (d) Lifting equipment shall be reliably and effectively earthed; otherwise, such equipment shall be deemed to be live, and barriers and obstructions shall be erected around it when it is used near live lines or equipment.
Ropes used near live lines shall be made of non-conductive material.
When erecting towers with the aid of lifting equipment near live transmission lines, the lines shall, where possible, be de-energized. Where this is not practicable, strict care shall be taken to maintain the minimum permissible clearances required under Table 1 of Chapter One.
When strong winds are blowing, or under the influence of other unusual natural factors that give rise to greater hazards, operations shall be suspended, except in cases of emergency repairs.
To ensure that permissible clearances are maintained while moving equipment under or near live lines, a responsible person shall be designated.
Work on Live Lines Using the Bare-Hand Method
In addition to observing the instructions set out in the other Chapters of this Regulation, Articles 48 to 68 shall also be observed when carrying out bare-hand-method work on live lines.
All workers shall have received training and practice in bare-hand-method work and in observing the related safety regulations before they are authorised to carry out work on live lines using the bare-hand method.
Before using the bare-hand method on high-voltage live lines or components, the following matters shall be examined: (a) the operating voltage of the circuit on which the work is to be carried out; (b) the permissible clearances of the lines and other live parts, on which work will be carried out, from the ground; (c) the permissible working voltage limits of the lifting equipment.
Only equipment that has been designed, manufactured, and tested for bare-hand-method work on live lines shall be used.
All operations shall be personally supervised by a person who has been trained in the bare-hand method and has acquired the necessary skill to carry out this work.
Automatic reclosing devices for circuit breakers shall, wherever practicable, be disabled before commencing work on live lines or equipment.
If there is a likelihood of lightning occurring at the workplace, the relevant operations shall be suspended.
In the bucket of the lifting device, a conductive shell or other suitable conductive means shall be provided for connecting the insulated section to the live line or equipment: (a) Workers shall be connected to the bucket shell by means of conductive footwear with leg straps, or by another suitable method. (b) Where necessary, having regard to the working voltage, an electrostatic shield appropriate to conductive clothing shall be used.
Before workers make contact with the live part on which they will be working, the conductive shell of the bucket shall be reliably connected to the live part and shall remain so connected until work on that part is completed.
Only tools and equipment designated for bare-hand-method work on live lines shall be used, and such tools and equipment shall be kept clean and dry.
Before raising the boom of the lifting device, the outrigger supports of the vehicle shall be adjusted to maintain its balance and stability, and the vehicle body shall be reliably and effectively earthed. Where making the earth connection is not practicable, protective barriers shall be erected around the vehicle, and the vehicle shall be deemed to be part of the live equipment.
Before placing the aerial-lift boom into working position, all controls (whether on the vehicle or in the bucket) shall be inspected and tested to establish that they are free of defects and to ensure that they are ready for operation.
Every day before starting work, or on each occasion during the day when work is to be carried out at a higher voltage, or when a change in working conditions requires an additional test, a leakage-current test of the boom shall be carried out. Aerial buckets used for bare-hand-method work on live lines shall be subjected to a leakage-current test. The test is carried out by placing the bucket in contact, for a minimum of 3 minutes, with a source whose voltage is equal to the voltage of the work to be performed; the leakage current shall not exceed 1 microampere per kilovolt (nominal phase-to-phase voltage). If any fault is observed in the operation of the equipment, the relevant operations shall be stopped immediately.
All lifting devices used in bare-hand-method operations on live lines and equipment shall have duplicate controls (lower and upper), in accordance with the provisions of paragraphs (a) and (b) of this Article. (a) Access to the upper controls shall be readily practicable for workers located in the bucket; if a lifting device fitted with two buckets is used, the controls shall be readily accessible from both buckets. (b) The lower controls shall be located near the base of the boom and shall take priority over the upper controls in issuing commands, such that, at any time, even while the upper controls are in operation, their commands can be overridden and cancelled from below and operated as desired.
Use of the lower controls of the boom is prohibited except when the person in the bucket has given permission for such use, or in emergency situations.
The minimum permissible aerial clearances for bare-hand-method work on live lines and equipment shall conform to Table 2. The aforementioned minimum clearances shall be maintained between the aerial device (bucket) and earthed objects, and likewise between the aerial device and lines and equipment whose voltage differs from the voltage connected to the bucket, unless the earthed objects or the lines and equipment referred to above are covered with insulating shields.
The minimum permissible aerial clearances in question shall also be observed while approaching, withdrawing, and while the bucket is connected to the live line.
When approaching or withdrawing from a live circuit, or making the connection between the bucket and the circuit, the clearances given in Table 2 shall be observed between all insulated sections of the aerial-lift boom and any other earthed parts (including the lower section of the boom and the vehicle).
When positioning the boom bucket near a live pin insulator or a live string of disc insulators, the minimum distance between all parts of the bucket and the earthed end of the insulator or string shall be observed in accordance with Table 2.
The use of any device (such as a rope or the like) to hoist equipment from the ground to the bucket or boom is prohibited.
Table 2 – Minimum Permissible Aerial Clearances for Bare-Hand-Method Work on Live Lines, for Alternating Current
| Voltage between phases (kV) | Phase-to-earth clearance (m) | Phase-to-phase clearance (m) |
|---|---|---|
| 11 and below | 0.6 | 0.6 |
| Above 11 up to 33 | 0.7 | 0.7 |
| 63 | 0.9 | 0.9 |
| 132 | 1.0 | 1.5 |
| 230 | 1.5 | 2.50 |
| 400 | 3.5 * | 6.0 * |
* This clearance may be reduced, provided that the distance selected is not less than the clearance from the live parts to earthed parts.
In the bucket of the lifting device, no conductive object other than connecting wires (jumpers), reinforcing wires, or work tools, with a length exceeding 0.92 metres, shall be present.
Ropes made of non-conductive material may be used between the line and the ground, provided that they are not supported with the aid of the bucket.
The bucket and the upper insulated section of the boom shall not be subjected, for the purpose of lifting or holding a load, to forces exceeding the force recommended by the manufacturer. (a) The table of minimum permissible aerial clearances for bare-hand-method work on live lines (Table 2) shall be printed on a durable, non-conductive panel and installed inside or near the bucket in a manner visible to the boom operator. (b) It is recommended that insulating measuring rods be used to check the minimum permissible aerial clearances for work on live lines.
This Regulation, comprising 68 Articles and 2 Notes, was drawn up pursuant to Article 47 of the Labour Code, and received final approval at the 451st session of the Supreme Council for Technical Protection, held on Tuesday, 1353/12/6 (25 February 1975), and is enforceable.