ELECTRICAL PRACTICES FOR CONSTRUCTION WORK

Transcription

1 CONTRACTOR S CHECKLIST ELECTRICAL PRACTICES FOR CONSTRUCTION WORK 2007 WorkCover. Watching out for you. New South Wales Government

2 Disclaimer This publication contains information regarding occupational health, safety, injury management or workers compensation. It includes some of your obligations under the various workers compensation and occupational health and safety legislation that WorkCover NSW administers. To ensure you comply with your legal obligations you must refer to the appropriate Acts. This publication may refer to WorkCover NSW administered legislation that has been amended or repealed. When reading this publication you should always refer to the latest laws. Information on the latest laws can be checked at or contact WorkCover NSW

3 What is this checklist about? This checklist will help contractors and sub-contractors engaged in building and construction work understand and apply the provisions described in the Code of Practice Electrical practices for construction work (the Code) as it relates to their work. The checklist is intended to provide a general overview of the key provisions relating to switchboards, portable plug-in electrical equipment, residual current devices, inspection and testing, portable generators and other electrical practices for construction work. For more detailed guidance you must refer to the Code. 1. Are construction site switchboards properly constructed and set up? Ensure that construction site switchboards are of robust design, mounted securely and are constructed from materials able to withstand mechanical damage. Construction switchboards should have: a protective cover or door that will not damage power cables when closed a way of keeping the cover or door open for electrical installation work be connected to the incoming electricity supply by a direct method, eg wired to terminals and not by socket outlets or connecting devices an extension lead tie-bar to prevent strain on the plug and socket outlet connection insulated cables stands for the support of cables and extension leads off the ground weatherproofing if located outdoors or anywhere subject to water exposure a clear area of 1 metre at the front of the switchboard isolating switches/ circuits breakers and RCDs that are to be clearly marked to indicate their function a lockable cover over circuit breakers and RCDs. Note: Where the electrical installation comprises only one final sub-circuit the fitting of a lockable cover over the circuit breaker and RCD is not necessary. 2. Are RCDs (safety switches) fitted? All final sub-circuits of construction wiring must be protected by 30mA Residual Current Devices (RCDs). This includes construction lighting, socket outlets supplying hand held or portable equipment and relocatable structures (site sheds). The RCD must be located at the switchboard where the final sub-circuit originates. Where construction work supply can only be obtained from permanent wiring, the electrical equipment must be protected by an RCD located in accordance with one of the following: at the switchboard at the origin of the final sub-circuit supplying electrical equipment incorporated into the socket-outlet supplying the electrical equipment incorporated into a portable socket outlet assembly arranged for connection to a socket outlet either directly or by means of a flexible cord of maximum length 2m and a plug. Ensure that all fixed and portable RCDs are tested for tripping current and operating time by a licensed electrician or a trained competent person every three months. The tripping function of portable RCDs should be checked before use by operating the RCD s test button. 1

4 3. Is construction wiring identified and protected from mechanical damage? Construction wiring must not be tied to, bundled, or grouped with permanent installation wiring. Where a risk assessment identifies a risk of damage to cabling, and the cabling cannot be relocated to an alternative position, it must be protected from mechanical damage by a suitable enclosure or barrier not less effective than: medium duty rigid PVC conduit heavy duty corrugated conduit flexible electrical hose. The following are some examples of (but not limited to) situations where cabling would require mechanical protection: cabling run on exterior surfaces that may be subject to mechanical damage cabling run on perimeter construction fencing permanently secured in the ground Note: Cabling should not be attached to relocatable type port-a-fencing unless the fencing is permanently secured to the ground. cabling which may came into contact with unearthed metal structures being installed as part of the construction process, (ie scaffolding etc) cabling run across or over metallic roofs or edges cabling run in hostile environments, ie a trench filled with debris and/or water. Further examples of where cabling would require mechanical protection are found in clause 4.6 of the Code. Construction wiring should be readily distinguishable from permanent installation wiring by using cable of a different colour, or by attaching iridescent yellow tape printed with the words Construction Wiring. Also ensure that there is no unauthorised work on portable buildings, such as drilling, nailing, screwing and fixing attachments. 4. Are flexible extension leads being used safely? Check that leads are not lying in mud or water or in areas where they can be damaged or become tripping hazards. Leads should be run on hangers or stable stands to provide a safe route through the work area and passageways and to provide sufficient height clearance for personnel and vehicles. Clearances of at least 2 metres should be maintained in work areas where personnel work. Do not allow leads to be wrapped around scaffolds or falsework, use temporary hangers that are covered with a non-conducting material to prevent mechanical damage. Where the requirement to suspend flexible cables and extension leads may not be practicable because of construction sites being on open ground, precautions must be taken to prevent damage to the cables or leads that may be caused by the construction work activity. Where extension leads are linked together and used outdoors or in situations such as metal roofs or decks or where water may be present, the extension socket and plug should be protected by design or enclosure against separation of the plug and socket or the ingress of water. Note: There are proprietary manufactured weatherproof screw-type coupling accessories designed for this purpose. 2

5 In the case of a single unit dwelling house site, a risk assessment should be undertaken to determine the likelihood of the cabling being damaged. Where the risk assessment identifies a risk of damage to cabling, appropriate risk control measures should be used for example, running cables on hangers or stands. 5. Are the correct type of socket outlets being used? Check that only 230 volt 10 ampere sockets with double pole switches are used on relocatable structures and sockets outlets supplying portable electrical equipment. 6. Are portable outlet devices suitable? Double adaptors, three-pin plug ( piggy back ) adaptors and other types of domestic multi-plug power boards are not permitted for construction work and must not be used. Portable outlet devices, being a plug-in device commonly known as a power board that provides one or more socket-outlets, may be used for the connection of plug-in electrical equipment subject to the following conditions: robust double-insulated construction and a minimum rating of IP 33 switches controlling the socket outlets are to be double pole socket-outlets mounted on the assembly are protected against damage by extended sides or covers incorporates overcurrent protection device with a maximum current rating of the supply flexible cord incorporates RCD protection with a maximum residual or tripping current of 30mA. Note: The RCD may be fitted at the plug attached to the supply flexible cord fitted with a heavy-duty sheath type flexible cord having a maximum length of 2.0m and a three-pin plug. Note: The use of an extension lead is allowed when using a portable outlet device provided the extension lead is plugged into a socket outlet that is RCD protected at the power source. If the socket outlet is not protected by an RCD an extension lead cannot be used in this configuration and the portable outlet device (complying with the above requirements) must be plugged directly into the socket outlet. Refer to Figure Are electrical tools and flexible extension leads in a safe condition? Ensure that extension leads and power tools brought onsite are suitable and in good condition. Always visually inspect extension leads and tools for signs of damage before use. Make sure unserviceable tools or extension leads are immediately withdrawn from service. The following conditions apply to extension leads: plugs and sockets must be either a non-rewirable, (moulded) type or a transparent type ensure that plugs and cord extension sockets are wired identically and that the identity of actives, neutral and earth connections are preserved in a like manner flexible extension leads must be heavy-duty sheath flexible cords. Note: The types of cables normally used as construction installation wiring must not be used as flexible cords or extension leads where the flexible extension lead passes through scaffolding or other metal structures, they must be run on hangers covered with non-conducting material to prevent mechanical damage 3

6 the sheath of a flexible extension lead must not contain the colour green. This is to avoid potential confusion with individual earthing conductors The maximum length of a power tool lead is 5 metres when connected to a flexible extension lead The maximum length of the most common types of flexible extension leads are listed below: Current rating (A) Conductor size (mm 2 ) Maximum length (metres) Figure 1: Guide to electrical practices on site Switchboard fitted with isolating switch, over current protection and 30mA RCD s. Lockable cover to be closed with leads connected through bushed holes in the base. Bushed holes. Max length of 10 amp (1.5 sq mm) extension lead is 35 metres. Two extension leads can be joined together provided the total length does not exceed the maximum length described in Section 7. Portable outlet device must include over current protection and 30mA RCD. Board to be solid and robust, securely fixed. Insulated or non conductive electrical lead stands. Portable electrical equipment and extension leads must be regularly inspected, tested and tagged and records kept. Maximum length of power tool lead is 5 metres. Note: The use of a flexible extension lead, as illustrated in Figure 1 is allowed when using a portable outlet device provided the extension lead is plugged into a socket outlet that is RCD protected at the power source. If the socket outlet is not protected by an RCD a flexible extension lead cannot be used in this configuration and the portable outlet device (complying with the above requirements) must be plugged directly into the socket outlet. 8. Has the portable electrical equipment been tested and tagged? All portable electrical equipment, flexible extension leads and portable power tools must be visually inspected regularly for wear and be tested in accordance with the Australian/New Zealand Standard, AS/NZS Note: Tags must be legible and may be colour coded to identify the month in which the testing and tagging was performed. 4

7 Testing must be undertaken by a licensed electrician or a trained competent person not qualified in electrical work, but who has obtained competency to carry out inspection and testing of portable electrical equipment using a portable appliance tester. This class of person is restricted to only carry out testing and tagging activities as described in this checklist. Note: For further guidance on the competencies of a trained competent person refer to the WorkCover Guide Competent Person for Testing and Tagging Electrical Equipment. Testing must be undertaken in accordance with the following testing intervals: prior to its introduction to service on a construction site at regular three monthly intervals for single unit dwelling house sites at regular monthly intervals for all other construction work, except if an electrical equipment risk assessment report determines that inspection and testing shall be carried out by a licensed electrician at regular three monthly intervals. Refer to Clause in the Code for requirements when undertaking an electrical equipment risk assessment. 9. Have you kept records relating to your electrical equipment? A record register of inspections, tests (including Certificates of Compliance Electrical Work) and maintenance regarding electrical equipment must be kept by the contractor. A copy of records should also be kept on site. Records must be produced to an Inspector, electricity network operator, principal contractor, contractor, elected OHS representative or authorised representative within 24 hours of a request being made. Ensure that details in the record register are legible and show the: date of the inspection plant number or inspection number of the item inspected results of the tests and inspections details of any repair/maintenance work required as a result of the inspection license/certificate number, printed name of the competent person (licensed electrician or trained competent person) who carried out the inspections and tests. 10. Are portable generators suitable? Temporary electrical supply for construction work should as far as reasonably practicable be obtained from the electrical distribution network. If this source of electrical supply is not reasonably practicable, it can be obtained from alternate means such as portable generators. The use of portable generators should be limited to work of a short duration or one-off applications. If portable generators are used on site, ensure the generator: complies with Australian Standard AS 2790 and is fully serviceable and has been properly maintained where supplying a fixed installation has been installed and tested by a licensed electrical contractor in accordance with the requirements of the Australian/New Zealand Standard, AS/NZS Wiring Rules where supplying portable electrical power tools and electrical equipment is fitted with a 30mA RCD. For further guidance on the electrical installation and use of portable generators refer to Chapter 6 of the Code. 5

8 11. Are portable lights being used safely? Install adequate artificial lighting to illuminate the work area if there is insufficient natural lighting. Portable light fittings must be fitted with a mechanical guard for the lamp and be of adequate stability. 12. Are plant and temporary structures a safe distance from overhead power lines? Make sure there is always a safe distance between live overhead power lines and cranes, concrete boom pumps, earth moving equipment, elevating work platforms, hoists, scaffolds, falsework, portable ladders and materials by observing safe work clearances. For further guidance on safe work practices in close proximity to overhead power lines refer to the Code of practice Work near overhead power lines. Acknowledgement In developing this checklist WorkCover NSW has drawn on information contained in a similar electrical safety checklist issued by WorkSafe Victoria. WorkCover NSW acknowledges that publication, which has been incorporated in parts of this checklist. Further information Detailed guidance for safe electrical practices for building and construction work can be found in the Code of practice Electrical practices for construction work. For information about the wide range of other codes of practice, certification guides and publications on OHS, rehabilitation and workers compensation contact the the WorkCover Assistance Service on: or visit The following guides provide useful information about construction work: Competent Person for Testing and Tagging Electrical Equipment Hazpak! Making your workplace safer Identification Tool for Electrical Hazards on-site Subby Pack OHS contractor management tool Dangers of Power Lines when Pumping Concrete WorkCover Safety Alert Tiger Tails Information on the latest laws can be checked at or contact Australian Standards can be purchased from SAI Global by contacting the Customer Service Centre on or over the net at 6

9 SAMPLE ELECTRICAL HAZARDS INSPECTION CHECKLIST ELECTRICAL HAZARDS INSPECTION CHECKLIST Completed by: Date completed: / / Contractor: Address of construction work: Construction site Electrical switchboard Is the switchboard of robust construction, secured in place and fitted with an extension lead tie-bar? Is there clear space in front of the switchboard of at least 1 metre? Is there a main switch to isolate the power and is every switch and circuit breaker clearly labelled? Can the switchboard cover be closed without damaging the flexible extension cords when they are connected to the socket outlets? Is the switchboard door capable of being locked to prevent unauthorised access? If applicable, is the switchboard weatherproof? Is the construction wiring connected to the switchboard protected from mechanical damage? Socket Outlets (Power points) Are all socket outlets on the switchboard protected by 30mA RCDs? Are all socket outlets secured in position? Are all socket outlets free of obvious defects? (Not chipped, cracked or showing signs of overheating). Extension Leads and Power Boards Are flexible extension leads, power boards and portable power tools in a safe operating condition? (No damaged insulation, burn marks, bent or loose pins) Are extension leads heavy duty, of the correct length and current rating? If applicable, are extension leads run on hangers or stable stands? Are plugs and sockets of the non-rewireable (moulded) or transparent type? Have extension leads, power boards and other portable plant been regularly tested and tagged by a licensed electrician or a trained competent person? Are the tags on all electrical plant and equipment within the specified testing date? RCDs (Residual current device) Is there a 30 ma RCD fitted at the site switchboard or a portable 30mA industrial type RCD unit available to use with the electrical equipment? Have RCDs been regularly inspected and tested by a licensed electrician or a trained competent person? 7

10 General Are mobile plant, tools and temporary structures kept a safe distance from overhead power lines? Are portable generators suitable for the task and protected by a 30mA RCD? Are records kept of all inspections, tests, maintenance and if applicable electrical risk assessment reports? Are portable power tools regularly inspected for damage and wear and maintained in accordance with the manufacturer s instructions? OTHER INSPECTION ITEMS: If you have marked a NO box on the inspection checklist, you need to take appropriate action to eliminate or control the hazard. 8

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