Purpose
This document describes the methods required for carrying out work near overhead or underground electrical power lines within our company.
Scope
This procedure applies to all employees of the company who are performing work in the vicinity of overhead or underground electrical lines and includes its contractors.
Guidelines
This guideline should be read in conjunction with 2.2.8 Electrical Incident.
Overhead Powerlines
The risk of working near overhead power lines shall be assessed prior to starting work. The identification and assessment of the risk must be done as early as possible in the planning stage of works. Planners and other officers who may be involved in the process of work planning must identify work areas and processes that could require equipment to be operated in the Safety Observer Zone or Exclusion Zone. Notes on the risk are to be made in the work planning documents, and if required, the necessary approvals obtained prior to the work start date;
Risks to be considered may include:
- A person contacting live conductors;
- Equipment contacting live conductors;
- Equipment contacting and damaging overhead lines (live or de-energised) and associated equipment;
- Equipment being dropped from above onto exposed electric lines; eg. while operating a crane over powerlines.
- Overhead electric lines are to be treated as being live unless otherwise confirmed in writing by the Overhead Electric Line Owner;
- Communications cables such as those used by Optus and Telstra for the Internet and cable television carry up to 100 volts and are to be considered as insulated low voltage overhead electric line;
- A reduced Exclusion Zone of 1 m applies to communication lines;
- No person, including contractors, on a workplace is to enter the Exclusion Zone for overhead electric lines unless:
- Written “safety advice” is obtained from the Overhead Electric Line Owner; and
- The work is authorised by senior Management using a ‘Work Permit’.
No person, including contractors, on a controlled workplace is to operate any item of operating plant within the Safety Observer Zone for overhead power lines unless:
- authorised by the ‘Work Permit’; or
- the person is an “Authorised Person” or an “Instructed Person” and has approval for the work under a ‘Work Permit’. These persons have reduced Exclusion Zones, depending on the voltage and type of conductor.
- The supervisor has the responsibility to ensure that no person, item of operating plant, or vehicle enters an Exclusion Zone unless written notification has been made to the Owner of the overhead powerlines, and a written “safety advice” has been received from the Owner;
- The supervisor has the responsibility to ensure that no item of operating plant or vehicle enters a Safety Observer Zone unless adequate control measures are in place to minimise the risk of the plant entering the Exclusion Zone. Some of the control measures that should be considered include:
- An alternative way of doing the task may be found that eliminates the need to enter the Safety Observer Zone;
- Erect a physical barrier to prevent any part of the machine or equipment from encroaching the exclusion zone;
- Use limiting devices on the machine;
- Use a safety observer when the machine is operating in the safety observer zone; and/or
- Issue insulating gloves to anyone who may come into contact with the crane or the load being moved.
Exclusion Zone and Safety Observer Zone
- No vehicle is to be operated closer than 1m from overhead lines;
- Notice of the need to enter the exclusion zone must be provided to the Owner of the overhead electric line. In most cases, this will be (Regional) Ergon Energy or (Brisbane) Energex. Other owners of overhead power lines may be Powerlink.
Note: At the time of notification, the exact location of the overhead power lines will be required.
- The allowable time frame for the owner of the line to respond to the written notice is up to 7 days after receiving the notice. The response will be a site meeting between Ergon Energy (or another owner) and a company representative, the issue of a written advice and quotation for any work required. These timeframes are maximum times. Actual response times could be shorter. A similar process will apply for other Owners of electric lines;
- It is, therefore, necessary to notify the Owner well in advance of the start date of the work to be done;
- Work is not to start until the written advice from the owner is received and the required controls are implemented; and
- After the lines have been de-energised, or other controls put in place to allow work to proceed in the Exclusion Zone, the risk of the plant contacting and damaging the overhead lines may still exist. In this case, it is necessary to provide a safety observer who can communicate with the operator of the equipment to ensure that the lines are not contacted and that a reasonable separation is maintained. Details of how this is to be achieved are to be shown on the Work Permit.
Underground Electric Lines
- Any excavating or driving implements (eg. star pickets) into the ground presents a risk of contacting underground services;
- Before any excavation is done, or any implement is to be driven into the ground to a depth greater than 300mm, the person intending to do the work is to obtain approval from the Supervisor;
- In the work planning phase, the supervisor is to call “Dial Before You Dig” on 1100 to determine whether electrical cables or other services are located near the work site;
- If the presence of underground electric lines is confirmed, the Supervisor is to contact the relevant owner of the underground line, advise them of the proposed work, and arrange for the lines to be positively located by the owner or by using Council locating devices if suitable;
- Depending on the advice from “Dial Before You Dig”, a number of organisations may be involved – eg. water, communications companies
Note: It is likely that some old underground electric services will be at a depth of only 75mm and covered by concrete. If any concrete is encountered while digging, it should be carefully checked to determine if there are electric lines or other services below it.
The location and alignment of the underground service must be clearly marked and advised to operators of equipment or work crews who may need to drive an implement into the ground.
Training of Personnel
Authorised Persons and Safety Observers may operate plant within significantly reduced exclusion zones.
- Training of these employees in those competencies is essential and is to arranged by the PCBU (preferably the WHSO) refer to Register on Attachment B;
- Relevant employees are to be advised of the Working near Electrical Powerlines through conducting a toolbox talk for ‘Working Near Electrical Powerlines’
Role of the Safety Observer
- Where a safety observer has been appointed they:
- Need to be an adequately trained to perform the role;
- Shall maintain a safe distance from the work, plant, equipment and/or load they are observing;
- Wear the appropriate personal protective equipment;
- Shall have a direct view of the work, plant, equipment and load if it is operating near or within the safety observer zone;
- Shall not perform any other duty or observe any more than one activity while acting as safety observer;
- Shall be able to communicate effectively with the worker or operator of the plant/equipment at all times;
- The safety observer must warn the operator if any part of the work, plant, equipment or load is about to enter the exclusion zone; and
- Where possible, shall where possible mark the border of the exclusion zone with suitable markers eg. red warning tape or a line painted on the ground.
Performance Indicators
Indicators of Conformance with this procedure are:
- Project planning identifies overhead powerlines at least three weeks before work is due to start;
- No work is done in the safety observer zone without a permit;
- Permits completed correctly for all work in the danger zones for power lines;
- Written safety advice obtained for all work within the exclusion zone of overhead electric lines;
- Authorised Persons and Safety Observers are trained; and
- Relevant employees are to be advised of the procedure.
Exclusion Zone
Exclusion Zone in Millimetres
Definitions
Act – Electrical Safety Act 2002
Electric Line is any conductor of electricity that carries a voltage of more than 50V AC RMS or 120V ripple-free DC.
Authorised Person is a person who:
- has enough technical knowledge and experience to do the work that involves contact with, or being near to, the overhead electric line; and
- has been approved by the person in control of the electric line to do work that involves contact with, or being near to, the electric line, or is authorised to act for the person in control of the overhead line.
- Instructed Person is a person who is acting under the supervision of an Authorised Person.
- Safety Observer, in relation to the observing of the performance of electrical work, means a person –
- who is competent to help with the electrical work; and
- who is competent to rescue the person performing the
- electrical work and to provide resuscitation; and
- whose competence has been assessed in the last 6 months.
Safety Observer Zone is an area in which it is possible that any part of operating plant, a person working on an elevating work platform, or a load being moved could enter the exclusion zone of live electric lines.
Exclusion Zone for plant or work being performed under or near an overhead power line is the zone in which you are not allowed to enter. The exclusion zones for overhead electric lines vary depending on circumstances. In general, the exclusion zone for all overhead electric lines is 3 m. The exclusion zone for overhead communications lines is 1m.
Operating Plant is plant being operated for its intended purpose; unless the operation of the plant cannot materially affect the distance between the plant and any electrical part in relation to which there is an exclusion zone under this part. eg. tip truck tipping a load; a mobile crane in use; a vehicle-mounted elevating work platform in use.
A vehicle is any vehicle that is not an operating plant; eg. a tip truck in transit to deliver a load; a utility travelling on a work site.
Overhead Electric Line Owner is the person in control of the overhead electric lines. This will usually be Ergon Energy but may be another entity such as Powerlink.
High Voltage is voltage greater than 1000 volts AC, or 1500 volts DC.
A supervisor is a person in control of a workplace (eg. supervisor,person-in-charge, ganger or leading hand.