Groundwork – electrical safety
Posted on 19th August 2022
We recently took a trip into Central London to isolate power ready for soil test drilling works.
It’s important to do this when you are carrying out work that involves digging or disturbing the ground. If you come across buried cables there’s a risk that someone could be injured or die due to electric shock, or electrical arcs that could lead to explosions and burns, even if protective clothing is worn.
What you need to know
Damage can be caused when a cable is:
cut through by a sharp object such as the point of a tool
crushed by a heavy object or powerful machine.
Previously damaged cables might not have been reported or repaired and these can be a real danger. There are regulations about the steps you must take to use electricity safely at work.
Health and Safety Executive (HSE) guidance highlights how to manage the risks of digging near underground cables and the Electricity Networks Association (ENA) has published ‘Watch Out! Cables About’ with advice about the risks of underground electric cables.
What you need to do
Underground electrical cables aren’t always easy to see and many can look like pipes, so a visual inspection isn’t enough. Here are the steps you should take:
Planning – although cables will normally belong to a Distribution Network Operator (DNO) some could belong to organisations such as the highways authority or Network Rail, for example. Your risk assessment should include how to work safely taking in to account local conditions.
Before you start groundwork look for equipment nearby that might require electricity, find out who it belongs to, check whether there are underground cables and ask for plans of their location. You might need to ask the owners to visit the site to show you where the cables are.
Suitable equipment should be used to detect any underground cables and you might need to make them ‘dead’ before you start work. Electricity companies must give their customers five days' notice if their supply is going to be disconnected.
Cable plans – before you start work you will need to collect plans and details of all buried services in the area. If it’s an emergency you will need to work as if they are live.
Utility companies might not all use the same symbols on electricity cable plans so it is important to check their meaning. High-voltage cables might be shown on separate plans from low-voltage cables.
Cable locating devices – to be safe you should assume that plans only give an indication of location, so a competent person should trace cables using suitable equipment which should be used regularly while the work is taking place. Underground cables should be identified and clearly marked before any work begins.
Safe digging – work should follow safe digging practices once cable positions and routes have been identified with trial holes and final cable exposure should be dug using suitable insulated hand tools as necessary.
Please get in touch if you need advice or assistance about electrical safety when you are carrying out groundworks.
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