Electrical Awareness for Construction Activities. Overhead Power Lines & Underground Cables

Transcription

1 Electrical Awareness for Construction Activities Overhead Power Lines & Underground Cables

2 Electrical Awareness for Construction Activities Electrical appreciation Agenda Overview of the electrical distribution and supply network of SP Energy Networks The Consequences of getting it wrong & Emergency Procedures Basic overview of legislation & guidance Summary of applicable Health & Safety legislation GS6 & HS(G)47 requirements The HSE Approach

3 Distribution Network Power Station 400, ,000 Volts 400, ,000 to 132,000 Volts Grid Substation 132,000 Volts 132,000 to 33,000 Volts Bulk Supply Point DANGER KEEP OUT OF DEATH DANGER OF DEATH KEEP OUT DANGER OF DEATH KEEP OFF DANGER OF DEATH KEEP OFF 11,000 to Volts Secondary Substation 33,000 to 11,000 Volts Primary Substation DANGER OF DEATH KEEP OUT Heavy Industry 33,000 or 11,000 Volts 11,000 Volts Overhead Line Schools,Offices etc. 11,000 to Volts Pole Transformer Farm 415 Volts DANGER OF DEATH KEEP OFF 415 Volts Houses 230 Volts Street Lighting 230 Volts Volts Link Pillar DANGER OF DEATH DANGER OF DEATH Emergency Contact Numbers: Scotland England & Wales O Power Line & Cable Enquiries

4 400kV 275kV Transmission Line

5 132 kv Overhead Line 132kV to 33kV Bulk Supply Point

6 11000 to 415/230 Volt substations

7 11KV OVERHEAD LINE COMPONENTS INSULATOR: PREVENTS POLE/CROSSARM FROM BECOMING LIVE CONDUCTOR: CARRIES ELECTRICITY CROSSARM: SUPPORTS INSULATORS & CONDUCTORS JUMPER: CONNECTS ONE PIECE OF APPARATUS TO ANOTHER TRANSFORMER: REDUCES HIGH VOLTAGE to LOW VOLTAGE

8 OVERHEAD LINE APPARATUS POLE MOUNTED AUTO-RECLOSER (PMAR) Purpose to protect the line against faults

9 33kV Overhead Lines

10 Low Voltage Overhead Line

11 415kV 230 kv Link Pillars

12 Underground HV Cables

13 The Consequences of getting it wrong

14 Consequences of getting it wrong..

15 Consequences of getting it wrong..

16 June 1997,concrete pumping machine operator was electrocuted in Dumfries & Galloway volts Task - Construction of large silage pit Height of line complied with statutory requirements Site staff were aware of the presence of O/H line, concerns had been raised but driver was satisfied with the safety distance Immediate treatment for electric shock may have prevented fatality

17 Examples of Non Compliance

18 House with an unusual feature

19 Scaffold built adjacent to LV overhead line

20 Plant & equipment adjacent to overhead lines Storing materials below overhead lines

21 Emergency Procedures Central & Southern Scotland Power Loss & Emergencies Telephone: Cheshire, Merseyside & North Wales Power Loss & Emergencies Telephone:

22 Basic overview of legislation & guidance

23 Guidance Guidance Note GS 6 & HS(G) 47

24 Guidance & Information for those in control of any kind of work under or near to overhead electric lines Legal Obligations Hierarchy of control Precautions (specific to site activities) Pictorial examples of setting up your site Can be downloaded Free of Charge from the HSE website

25 Dedicated Point of Access / Egress 6m Minimum

26 Access/ Egress to be defined either side of OHL

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29 Consequences of Getting it Wrong

30 Consequences of Getting it Wrong

31 Consequences of Getting it Wrong

32 Consequences of Getting it Wrong

33 Consequences of Getting it Wrong

34 Obtain Plans Write Data Management Correspondence, SP Energy Networks 55 Fullerton Drive, Cambuslang, G32 8FA Phone Write - Data Management Correspondence (England and Wales), SP Energy Networks, Prenton Way, Prenton CH43 3ET Phone

35 Locating Underground Apparatus Check the plans by tracing the cables and mark their position using paint, crayon, chalk or pegs. Always scan the area you intend to excavate with a cable locator before you start to dig.

36 NOW DIG SAFELY Take trial holes by hand to find the exact position of cables before you use a mechanical excavator. Remember cables can be found at any depth - even just below the surface. If you find a cable embedded in concrete don t try to break it out, ask for help from EnergyNetworks If you cannot find the cables shown on the plans never assume they re not there, ask for help from EnergyNetworks Remember Electricity Can Kill

37 NOW DIG SAFELY If you do damage a cable keep everybody clear and immediately ask for help from EnergyNetworks Never attempt to move or repair a cable, treat all cables as LIVE

38 HSE Overview

39 What is the Overall Goal for HSE? Prevention of approximately 25 deaths and anywhere between 1000 and 3000 serious incidents per year as a result of electric shocks, electric burns, flashover/arc burn injuries, electrical fires and explosions. From HSCs Statistics of fatal injuries 2005/06 : 11 Fatal injuries to workers from contact with electricity/ electrical discharge

40 Hazards & Risks from Overhead Electric Power Lines Risks Personal contact with overhead electric lines can result in fatal injuries due to electric shock and/or burns sustained as current flows through the human body; Contact or close approach to lines made by metal parts such as a crane jib, raised tipper lorry, agricultural sprayer, etc can result in current flow through the vehicle frame with risk of shock and burns to persons in the immediate vicinity; Can also occur with non-conducting materials if damp or dirty. Actual contact with overhead line is not necessary to result in electric shock close approach may allow a flashover or arcing to take place.

41 Legislative Framework (3) Electricity at Work Regulations 1989 Regulation 4(3) requires all work on or near electrical system to be carried out so as to prevent danger, so far as is reasonably practicable; and Regulation 14 requires that no person should work on or near any exposed live conductor unless specific criteria can be satisfied, namely: Unreasonable for it to be dead; and Reasonable for persons to be at work on or near conductors whilst live; and Suitable precautions taken to prevent injury ABSOLUTE DUTY TO FULFIL REGULATION 14

42 Legislative Framework (4) Electricity Safety Quality & Continuity (ESQC) Regulations 2002 Specify requirements for overhead line construction for generators/distributors; minimum heights of lines and cables e.g. for voltages < 33kV: 5.8m(over roads)/5.2m(other locations) position, insulation and protection of lines; precautions against access and warnings of dangers.

43 What happens if non-compliant? Range of sanctions: Verbal or written advice; Improvement Notice; Prohibition Notice; Prosecution of company, directors and or employees. Actual action depends upon a range of factors: severity, previous history, attitude of employer or individual, public interest etc.

44 GS6