Purpose
This instruction describes the safety requirements when working from an EWP.
It does not attempt to replicate any detailed work practices or maintenance requirements contained in Power Training Services training documents or other relevant documents.
Instructions
EWP operators, occupants and safety observers
• All EWP operators must possess a licence to perform high risk work.
• All EWP operators and safety observers must be trained and competent in the use of emergency retrieval systems relevant to the EWP they are using (e.g. Leguan 110 has a manual recovery system).
Note:
Refresher training is to be undertaken every 12 months – a grace period of six weeks applies at the end of the 12 month period.
• The EWP basket operator must be competent in emergency descent rescue.
• The EWP ground-based operator:
o must be competent in the operation of the EWP
o must be qualified to perform the role of safety observer if a separate observer is not present
• In addition to operational personal protective equipment, all occupants of the EWP basket must wear an approved fall protection harness.
• The safety observer must be competent in the recognition of workplace hazards relevant to EWPs.
Using the EWP
• Perform the log book pre-start EWP operations check.
• The EWP must have an insulation rating equal to, or greater than, the voltage of any energised apparatus within the maximum reach of the boom and basket
Note:
• A minimum 132 kV insulated EWP must be used for 220kV and 330 kV transmission line and associated works.
• Adhere to the un-insulated clearances per Table 1 of field instruction 2.8 (Minimum approach distances) in this manual
• For vegetation works, refer to section 10 (Vegetation management work) in this manual.
o Insulated EWP’s must be electrically tested every six months (three week grace period) and the electrical test sticker in the cab of the vehicle must be replaced after the test is passed. An insulated EWP that does not display a current electrical test sticker or carry an electrical test certificate is classified as non-insulating and must not be used on the network.
• An EWP working within the HV minimum approach distance or close to low voltage must be fitted with an emergency descent device (EDD) that complies with Western Power specifications.
• Only operate an EWP when the wind velocity is less than 45 km/h, or 40 km/h when using a gin pole to lift conductors for live line high voltage (HV) work.
• Do not exceed the EWP basket safe working load. For Distribution aerial conductor weights, see the Conductor weights chart in Appendix 8 (Conductor weights).
• Always earth an insulated EWP at the vehicle earthing point to ground or a known earth when working in any of the following conditions:
o on or near live HV conductors
o on or near de-energised HV conductors Note:
EWPs with insulated booms working on or near de-energised and earthed/shorted conductors need not be earthed. However, the vehicle must be earthed when being used for the application of portable earths.
• Attach the fall protection harness to the EWP basket anchor point before operating the boom.
• Before operating an EWP, always ensure that:
o the EWP vehicle is level
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Work Practice Manual 2.6 Mobile elevated work platform (EWP) safety
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• When performing any work, stay inside the basket and have at least one foot on the basket floor.
• If transferring between an EWP basket and a tower structure or an approved working platform, always remain attached while transferring. All work processes are prohibited during the transfer movement.
• If more than one mobile plant is involved:
o if they are within a distance of five metres of each other, they should be connected (bonded) to a common earthing point
o if they are separated by more than five metres, each mobile plant should have its own direct earth connection applied
• When working near energised apparatus:
o Do not compromise the insulated fibreglass section of an EWP boom.
o Maintain minimum approach distances from live apparatus.
o Ensure portable earths are clear from the boom.
o Ensure extension leads for portable power tools are clear from the boom.
o Cover any exposed live conductors.
o Ensure that the spray-washing hose is disconnected to create a minimum 800 mm gap across the insulated section
• Everyone involved in EWP operations must maintain a ground approach distance around the base of the EWP (stabilisers/outriggers included) when used near live apparatus. If this is not possible, insulating gloves rated to the highest voltage within the boom reach on the structure must be used.
• Members of the public must not be allowed to come within the ground approach distance.
• A barrier must be in place around an EWP prior to the boom operation where inadvertent electrical contact may occur. For ground approach distances, see Table 1 (EWP ground approach distance (GAD)) and Figure 1 (Ground approach distance example).
• Earth stakes must be barriered to a minimum radius of one metre to guard against touch potential.
Table 1: EWP ground approach distance (GAD)
Voltage of conductor Ground approach distances (mm)
Low voltage 1,000
High voltage 1 kV up to 33 kV 1,200
66 kV 1,500
132 kV 1,800
Over 132 kV 3,000
(Based on industry practice, derived from step and touch potential calculations. If the above clearances cannot be maintained, insulating gloves rated to the highest voltage within the boom reach on the structure must be used.)
Figure 1: Ground approach distance example In an emergency
• If an EWP has mechanical failure and cannot be lowered, and the personnel are safe, they must remain in the bucket until a second EWP arrives onsite to effect a rescue.
• The EDD rope-style device is only to be used in time-critical, life threatening situations.
• Never tamper with the ‘deadman’ basket control to bypass its manual function.
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Uninsulated EWPs used in a substation
• Clearly define the worksite with barriers and signs. All assets within the worksite must be de-energised and earthed. Minimum approach distances (MADs) must apply between the worksite boundary and any live conductors to ensure the safety of personnel at all locations within the defined worksite.
• Observe the MAD of live or de-energised apparatus.
• Uninsulated EWPs working within substation sites must have the basket bonded to the hardware and the chassis connected to a known earth point using the approved earthing leads (either bolted or clamped).
• Uninsulated EWPs are not permitted to enter the MAD.
• Uninsulated EWPs can only be used on equipment that is earthed. Equipment under construction that is at risk of induced voltages must also be made safe by applying earths to ensure no potential rise is possible.
Travelling in EWP baskets
• A risk assessment must first be done to identify all foreseeable hazards and to ensure that risk controls are implemented.
• Comply with the conditions of Department of Transport exemption 46V11CP3TM.
• EWP booms must be kept in the stowed position.
• The vehicle must not exceed the speed of six km/h or the posted road speed limit (whichever is lower).
• People travelling in the EWP basket must wear a suitable safety harness and lifeline arrangement at all times.
• A copy of the Department of Transport exemption 46V11CP3TM must be carried within the vehicle when undertaking the conditions within it, and must be produced on demand.
Escorting a person in an EWP basket
• An escorted person is defined as someone who is authorised to ascend in an EWP basket but is prohibited from performing any operational work. They may observe, take photographs or make a movie on behalf of Western Power.
• An accredited EWP basket operator must accompany the escorted person.
• The EWP basket operator must provide the escorted person with an induction that includes the operation of the EWP and the correct use of the fall arrest harness.
• The EWP basket must not encroach the MAD.
• Lower the EWP basket using the base controls.
Cleaning and maintenance of EWPs
• Wash and clean the inside and outside of insulated EWP boom sections every six weeks or more regularly if used in harsh conditions.
• Use recommended methods and substances to polish the fibreglass. (Contact Western Power Fleet Services for advice on cleaning products.)
• After cleaning, rinse well with water to remove any residue.
• Ensure the insulated EWP boom sections are completely dry before using for work on live equipment.
• Report cracks or damage found in the fibreglass section of an EWP boom to the formal leader and do not use the EWP.
Contract EWP
A hired EWP operating on Western Power assets must be inspected prior to use in accordance with the Combined Elevated Work Platform and Crane / Borer External Hire Checklist (for an example, see Appendix 2 (Standard forms)).
References
• Work Practice Manual:
o field instruction 2.8 (Minimum approach distances) o section 10 (Vegetation management work)
o Appendix 2 (Plant hire sheet for contractor use) (DM# 6617609) o Appendix 8 (Conductor weights) (DM# 8735859)
• AS 2550.10—2006 – Cranes, hoists and winches—Safe use Part 10: Mobile elevating work platforms
• Department of Transport exemption from 46V11CP3TM (DM# 7438793)
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Work Practice Manual 2.7 Fall prevention equipment Page 1 of 2
2.7 Fall prevention equipment