7Scheduled inspections and maintenance#

7.1Electrical#

Periodic inspections and tests are required on the electrical installation to ensure compliance with the Act. Inspections and tests are to be carried out at a maximum of every six years. Where the risk of degradation of the installation due to environmental or other factors is considered high, more frequent inspections are to be carried out. Spot check audits on parts of high-risk installations are be carried out at a maximum of 12-month intervals. Typical high-risk factors may include corrosive environments, susceptibility to flood / submergence, devices nearing end of life, vermin habitats and high pedestrian activity.

Periodic verification of electrical installations is to be carried out in accordance with Appendix E.

Immediate electrical risks (including exposed live conductors, unearthed equipment and incorrect polarity) must be made safe and rectified when discovered and the ESO and District / Regional Management notified.

7.1.1Point of supply maintenance#

The road lighting installation power supply is distributed by the Electricity Entity's network infrastructure. Supply or point of supply (POS) can typically be from:

overhead pole mounted transformer with fuse
underground pit with fuse
pillar box with fuse from an underground supply, or
street lighting column connection.

Maintenance is to include a visual inspection of the point of supply for signs of degradation. Where there is any concern about the integrity of the point of supply or the upstream network, the Electricity Entity is to be advised.

7.1.2Electrical switchboard verification#

Maintenance is to be carried out to ensure the electrical integrity of the switchboard. As the switchboard is the point where lighting circuits originate and are controlled, it is important that all the components are in good condition.

Inspection is to include but not necessarily be limited to:

ingress of water and vermin
deterioration of weatherproof seals and other components
damage by rodents
detection of poor connections and joints
correct earthing
protection against direct and indirect contact with LV terminals / surfaces
correct operation of components
correct internal labelling of components
mounting or support for the switchboard enclosure, and
correct enclosure labelling and nameplates.

Electrical tests are to be carried out and documented in accordance with the Wiring Rules.

7.1.3Cable and connection maintenance#

Electrical cabling and connections are to be maintained to ensure a low impedance path for the electricity supply. While road lighting cable is expected to last in excess of 25 years under standard operating conditions, a number of factors (such as those previously mentioned) can reduce service life. Consequently, scheduled visual observations and electrical tests are required to ensure continued safety of the installation. Where cable temperatures are significantly high due to poor electrical connections or other issues, insulation damage can occur, which may ultimately result in fire. Clean cable termination surfaces, correct fixing tightness and the application of a protecting grease to terminations can assist in maintaining the integrity of the termination. Thermal imaging equipment can be a cost-effective method for assessing increased temperatures within the installation or early detection of high resistant joints.

Transport and Main Roads Technical Specifications now specify the use of either XLPE / PVC or XLPE / HDPE mains and sub-mains cabling for new installations. PVC / PVC cabling is not designed to be submerged in water for periods of time. The new standard cables are more resilient. Where there is a known water retention problem, the better-quality XLPE / HDPE cable should be used to replace PVC / PVC cables that have reached end of life.

Where waterproof cable terminations are not properly installed and maintained, water ingress can be a problem with subsequent degradation of the cable. Within the cable termination enclosure, the sheath is to be carefully peeled back clear of the insulation, and the bottom of the enclosure filled with a proprietary sealant to fill the area around the cable and the enclosure. The sealant is to encase the

insulation / sheath interface so that any moisture tracking between the insulation and sheath cannot enter the enclosure. Proper closure of the enclosure and maintenance of seals will assist in maintaining a waterproof termination. Poorly fitting enclosures are to be replaced.

Rodent and vermin attack, as well as poor installation methods, can also affect the integrity of the cable sheath. Where damage has occurred, moisture ingress and cable degradation will occur.

Where the rate of insulation resistance degradation reasonably suggests that the cable insulation will not comply at the next periodic inspection interval, inspection frequency is to be increased or rectification undertaken.

Inspection items are to include, but not be limited to:

joints, connections and terminations for corrosion
poor, loose, overheated or unsecured connections
evidence of moisture ingress to cables and/or connections
damaged insulation
exposed conductors
general condition of cable, and
evidence of rodent / vermin activity.

In accordance with the Wiring Rules, electrical tests are to be carried out on cables and results documented.

7.1.4Pits and conduit maintenance#

Pits and conduits are to be inspected visually. Once it has been determined that the conduit installation complies with the required depth, this need no longer be checked except where work to the ground surface has been carried out in the vicinity of the conduit.

Pit lids are to be intact, undamaged and properly fitted to the pit. Pits are to be free of damage, with no collapse of ground around the pit, no collapse of the inside of the pit, and with the pit top level with the surrounding surface. Pits are to be free draining.

Maintenance of pits and conduits is to include but not be limited to:

ensuring adequate drainage
replacement of broken or chipped pit lids
rectifying collapsed pit side walls and other damage, and
maintaining ground / pit surface level and pit surrounds.

Cement pits and ducts that contain, or are suspected to contain, asbestos materials are to be handled using safe work practices and qualified persons in accordance with workplace health and safety legislation and Transport and Main Roads procedures. All asbestos materials are to be identified and recorded in District Regional registers.

7.2Lighting#

Transport and Main Roads has now phased out the use of mercury vapour luminaires for Rate 3 installations. The department is currently implementing a luminaire replacement program to replace conventional light sources with LED technology. LED technology provides benefits of improved light source life and reduced rate of lumen depreciation.

When combined with the connection of LED luminaires to a control and monitoring system (CMS), this technology eliminates the need to undertake periodic light outage patrols. Faulty LED lights will be reported by the CMS.

For conventional road lighting, periodic inspections of the lighting installation are to be undertaken to ensure the lighting is operating as designed.

The maximum level of luminaire outages at any one time is not to exceed 5% of the luminaire population.

Routine luminaire maintenance is to be carried out at the following intervals:

conventional lighting – when replacing lamps (typically three years), and
LED lighting – six years.

Maintenance of luminaires is to include but not be limited to:

cleaning of all optical surfaces of the luminaire, both internal and external
checking of gaskets for deterioration and replacement where necessary
replacement of damaged / weathered diffuser
a visual check of the electrical components and wiring for signs of overheating
checking of all accessible screws, nuts and fixings for tightness
where undone, application of non-corrosive gel to screw fixing
realigning of the luminaire as per design as required, and
cleaning of heatsinks where fitted to ensure luminaires do not fail prematurely.

Where luminaries are installed in high pollution areas, more frequent cleaning may be required.

Note that LED luminaires have a 10-year warranty. No internal repairs are to be undertaken during the warranty period. A like-for-like replacement is to be made for luminaires under warranty. Smart Lighting Controllers (SLCs) are provided by the CMS provider, not the luminaire provider, and have a separate 10-year warranty.

Outside the warranty periods, replaceable parts are surge protectors, LED drivers and SLC.

Where a luminaire is damaged as a result of a pole crash, the SLC should also be replaced.

7.2.1Bulk lamp replacement#

Bulk lamp replacement (BLR) of high-pressure sodium lamps is to be carried out every three years.

BLR is where all lamps are replaced at one time, irrespective of their operational status. This corresponds with the design specification and to satisfy the requirements of AS/NZS 1158 Lighting for Roads and Public Spaces.

Additional information is included in Appendix D Bulk Lamp Replacement Interval.

After bulk lamp replacement has been initiated, spot lamp replacement inspections are to be carried out at least twice during the replacement cycle and more frequently if warranted by the number of failures reported. The rate of lamp mortality is not linear over time.

Where possible, the BLR should take into account the planned LED replacement program.

7.3Structural#

Periodic visual inspections are to be undertaken to ensure at least the following items are examined for compliance with the relevant standards:

steel poles
concrete poles
other luminaire supports (for example, under overpasses)
vertical distance between the pole slip-plane and surface level, and
slip base high tensile clamping bolt tension.

Inspections are to be carried out 12 years after original installation and then every six years thereafter.

Environmental conditions to which the road lighting installation is subject may require the frequency of inspections to be increased – for example, bridges / overpasses, corrosive environment and areas prone to flooding.

Structural inspections are to be completed in accordance with Structures Section requirements. (Note that a separate ITS and Lighting Structures Inspection Manual is under development)

7.3.1Steel pole maintenance#

Generally, once steel poles have been installed and commissioned, minimal maintenance is required; however, the following aspects are to be inspected as a minimum:

testing the thickness of galvanic protection at the pole base and other areas in accordance with AS/NZS 4680 Hot-dip galvanized (zinc) coatings on fabricated ferrous articles
pole vertical alignment tolerance check, and
surrounding area assessment.

The immediate area around the base of the pole is to be kept clear of debris and soil build up to ensure that the steelwork does not corrode.

Road lighting poles can suffer damage from both major and minor incidents. They are to be replaced when any of the following damage is evident:

horizontal cut(s) or tear(s) exist and exceeds 20% of the pole circumference
deformation of pole due to impact exceeds 20% of the pole diameter, or
hatchway door cannot be securely fastened or is damaged to the extent it cannot be replaced or repaired (even if the pole is not damaged).

Where sharp edges are present, but it is not considered necessary to replace the pole, the edges are to be rectified to remove the risk of personal injury. Where hatchway doors and/or fixings are damaged and can be replaced without the need for replacing the pole, the damaged part(s) are to be replaced.

Welding on poles is only to be undertaken at the initial pole fabrication stage. No additional welding of poles is to be undertaken.

7.3.2Concrete pole maintenance#

Concrete road lighting poles are to be replaced when any of the following damage is evident:

where the concrete has been cracked or damaged to the extent that the reinforcing is subject to corrosion, or
if the hatchway door cannot be securely fastened or is damaged to the extent that it cannot be replaced or repaired (even if the pole is not damaged).

Where hatchway doors and/or fixings are damaged and can be replaced without the need for replacing the pole, the damaged part(s) are to be replaced.

7.3.3Pole slip-plane and surface level#

Some road lighting poles employ a ‘Slip’ base fixing type which enables the pole to be displaced safely in the event of being directly impacted by a vehicle during a road crash. The intent of this design is to limit the damage caused to the vehicle and potentially reduce injury to vehicle occupants.

To ensure that the slip base mechanism will continue to activate effectively in the event of an impact collision, the distance between the slip-plane and the ground surface is to be checked in accordance with the following:

Clause 8.3.5.2 of MRTS92 Traffic Signal and Road Lighting Footings
Transport and Main Roads Standard Drawing 1380 where no crossfall exists
Transport and Main Roads Standard Drawing 1381 where crossfall exists, and
Transport and Main Roads Standard Drawings 1382, 1429 for crossfalls between 1:6 and 1:3.

These checks are to be continued over time as the surrounding surface level may change, such as due to the following examples:

natural settling of surrounding earth
water erosion, and/or
landscaping.

Where the slip-plane height is not correct, this is to be prioritised for rectification works.

Any debris or soil build up in the slip base recess is to be removed to ensure that the steelwork does not corrode.

7.3.4Slip base high tensile clamping bolt re-tensioning#

The tension of the high tensile clamping bolts (HTCBs) are set at installation in accordance with MRTS92 Traffic Signal and Road Lighting Footings and Transport and Main Roads Standard Drawings 1380, 1381, 1382 and 1429. Over the life of the road lighting installation, the HTCBs may require re-tensioning to ensure that the integrity of the slip base safety mechanism is upheld.

Re-tensioning is to be done in accordance with Structures Section recommendations. Refer to TN64 Tensioning and Re-tensioning of Slip Base Lighting Pole Bolts.

Inspect clamping bolts and shear washer for visual signs of damage.

7.3.5Slip base pole clamping bolt tethering systems#

Clamping bolt tethering systems, where installed, prevent bolts from being projected at high speed or a long distance from the pole upon impact by errant vehicles.

Inspect the components of tethering systems for damage or deterioration and replace if required.

Tethering systems are to be installed in accordance with Standard Drawing 1755 Slip Base Tethering System for Transport and Main Roads Rate 3 Lighting Poles and Technical Note TN200 Slip Base Pole Clamping Bolt Tethering System Installation.

7.4Environmental#

7.4.1Vegetation management#

The growth of vegetation near luminaires has the potential to reduce significantly the effectiveness of road lighting installations. Where vegetation or other obstructions have, or may have an impact on road lighting performance, they are to be removed or otherwise treated to remove the risk.

Vegetation may also reduce security, increase the likelihood of vermin and/or hinder access to switchgear and electrical pits and is to be managed accordingly. Concrete surrounds should be installed around equipment, particularly switchboards.

7.4.2Vermin#

Evidence of vermin infestation is to be removed, and damage caused by vermin is to be rectified. The installation is to be treated / modified to prevent / minimise the likelihood of reinfestation.

7.4.3Maintenance access#

Where necessary, access to sites is to be remedied to allow safe, all-weather access by maintenance personnel.

7.4.4General tidy up#

Each site is to be cleaned of all waste / rubbish so as to present a clean, tidy area that reflects well on Transport and Main Roads.