Use of ‘goal posts’ and other measure to avoid contacts with overhead power lines – views invited

Monday 14 October 2013

A recent TV farming programme (BBC2 Scotland's 'Landwards', broadcast on 4 October 2013) featured an interesting item on avoiding contact with overhead power lines (OHPL).

This was in the same week that delegates at the Machinery Safety Workshop [organised by IOSH/RIG on behalf of the Farm Safety Partnership (FSP)] identified this hazard as a major concern of those working in the industry, especially as the height and reach of machines continues to increase.  This was reinforced by being told that ~1500 OHPL contacts on farms are already reported each year.

To reduce this risk, a power distributor’s Field Engineer interviewed on the programme suggested that temporary 'goal posts' should be erected (mid-span) to create a single safe route for a telehandler to cart bales across a field to a trailer under an 11kV power line and ensure the load and/or boom were kept 2.3 m below the line.   [nb. Remember that 5.2m is the legal minimum height of power lines up to 33kV in fields, but this might be less, eg within the ‘10m safety zone’ where ‘droppers’ (live wires and/or hardware such as transformers, etc) are fitted to poles.]

This specific advice does go further than current guidance from HSE and others,  and it has already generated some discussion within RIG about what is ‘reasonably practicable’ in such situations.  We would welcome your views, to inform a possible FSP/Energy Network Association (ENA) ‘OHPLs’ Working Group to review current guidance and identify any new methods to avoid contacts and ways to promote safe practice.

Whilst ‘goal posts’ provide a useful visual and mental prompt and some farmers do already install them at points of access to working areas in fields for trailers or lorries, some may consider erecting temporary goal posts in the middle of fields during harvest operations is not ‘reasonably practicable', eg due to the size or shape of fields or low frequency of access. 

One alternative ‘technical’ solution suggested at the recent Machinery Safety Workshop was the use of proximity sensors or alarms to alert operators as they approach OHPLs. However, suitable devices for in-field use are not known to be available.  These were discounted in previous discussions a few years ago because devices available at that time were unreliable and unsuitable for use on tractors and other machines, particularly where different voltage lines cross fields.

However, with the significant improvements in GPS and e-mapping systems over the past few years, together with automatic control and the potential to link these with machine electro-hydraulic control systems, such devices might now be feasible. Any thoughts on the potential for this are welcome.

Meanwhile, a more practical precaution is to identify safe working areas in fields and work each side of OHPLs to avoid crossing under them. Many farmers now align their tramlines with OHPLs to avoid crossing under them with high machines.

It is advised that this approach should be supported by a clear (written) SSOW, reinforced by briefing of any drivers – including contractors and visiting drivers. Particular situations should also be discussed and suitable precautions agreed with the appropriate ‘Distribution Network Operator’ (DNO).

Please let us know what you think and if you are willing to contribute to the proposed (possibly ‘virtual’) Working Group, by contacting Alan Plom, Chair of the FSP’s Machinery Safety Group.

Detailed guidance is available in HSE’s Agricultural Information Sheet (AIS8) Working safely near overhead electricity power lines and the leaflet Safety Focus on Electricity, now available on the FSP’s new website.

The Energy Networks Association leaflet Safety Information for Farmers & Agricultural Contractors has also recently been reissued.