Overhead power lines should be at a minimum clearance from the ground of 5.2 metres (17 feet). However, live equipment fitted on poles may be as low as 4.3 metres (14 feet).
If a machine or other conductive item of equipment comes into contact with a live overhead electricity power line, electricity will be conducted through it to earth. You do not need to touch the line, as in some circumstances electricity can flashover or arc (it can jump across gaps). Anyone touching a machine or equipment in these circumstances risks a serious or fatal electric shock.
UK Power Networks is urging extra vigilance and awareness of the risks of coming into contact with or getting too close to overhead power lines. Their free leaflet can be downloaded here ’Think before you work on your land and you can contact them on www.ukpowernetworks.co.uk/internet/en/safety to order free vehicle cab stickers to remind you to “Look up, Look out!”
If you follow these simple safety precautions when operating machinery, it could save your life:
- Find out the maximum height and maximum vertical reach of your own and your contractors’ machines;
- Find out the location of underground electricity cables and overhead electricity power lines on your land.
- Contact UK Power Networks, or your local distribution network operator, for copies of plans showing where equipment is. They can also provide advice on line heights, minimum vertical clearance distances and precautions to take. Distribution Network Operators can also arrange to have the height of the lines checked. Operating voltages are displayed on signs attached to steel towers.
- Always tell visitors, contractors or casual workers where electricity cables and lines are positioned.
- Always check around you when loading or unloading vehicles or stacking materials.
If you come into contact with an overhead power line:
- Stay in the cab of the machine and lower any raised parts in contact with the line or try to drive the machine clear, if you can
- Inform the Distribution Network Operator immediately (display the telephone number in the cab or keep it on your mobile phone).
- Electrocution is possible if anyone touches both the machine and the ground at the same time. If you need to get out jump well clear so that no simultaneous contact is made between you, the vehicle and the ground. Do not touch any wires. Stay clear and warn others not to approach.
- Get the Distribution Network Operator to disconnect the supply. Even if the line appears dead, do not touch it, or any part of the machine. Contact with the line may cause the power supply to trip out temporarily and it may be reconnected and re-energised automatically, without warning.
- Never touch an overhead line that has been brought down by machinery, or has fallen, eg in a storm. Do not try to disentangle equipment, until you have received confirmation that the line has been de-energised and made safe.