Electrical Safety Construction: The Basics Explained

Electrical safety on a construction site means making sure electrical systems and equipment are safe, kept in good condition, and that nobody works on or near live parts without proper control. The Electricity at Work Regulations 1989 set out these duties in law. Electric shock and burns can kill or seriously injure, and site conditions such as damp, damaged cables and heavy plant make the risks higher. This guide explains the rules in plain English and the habits that keep you safe.

Key takeaways

What the Electricity at Work Regulations 1989 require

The Electricity at Work Regulations 1989 apply to all work activities involving electricity, and they place duties on employers, the self-employed and employees. They are written in terms of preventing danger, so the standard is whether the risk has been properly managed. In plain English, the main ideas are:

• Systems must be safe. Electrical systems must be constructed and maintained so as to prevent danger, as far as is reasonably practicable.
• Equipment must be suitable. It must be fit for the conditions where it is used, including weather, damp, dust and mechanical damage.
• Protection must be provided. Systems need suitable protective measures, such as devices that cut off the supply in a fault.
• Live work is a last resort. Work on or near live conductors must be avoided unless it is unreasonable for them to be dead, and unless it is reasonable to work live. Where live work does happen, suitable precautions must be taken.
• People must be competent. Anyone working on electrical systems needs the technical knowledge or experience to prevent danger, or must be properly supervised.

The legislation page gives the exact wording of each regulation. The HSE electricity pages explain what these duties mean in practice for different kinds of work.

Hazard and risk with electricity

The main hazards are electric shock, burns, fire and explosion. Shock can happen through direct contact with a live part, or through a fault that makes metalwork live. Burns can come from an arc as well as from direct contact. If you want to refresh the distinction between a hazard and a risk, the guide on hazard vs risk explains it. For electricity, the hazard is the energy in the system, and the risk depends on how likely you are to be exposed to it and how serious the harm would be.

Site conditions raise the risk. Wet ground, damp surfaces, temporary supplies, cables lying in walkways and tools used hard day after day all make faults more likely. This is why site electrical equipment has to be chosen, installed and checked with those conditions in mind.

Everyday electrical safety on site

Tools and equipment

• Check tools, leads and plugs for damage before use. Look for cuts, exposed wires, cracked casings, loose connections and signs of burning.
• Do not use any equipment that is damaged or that has been repaired in a makeshift way, including with tape. Take it out of use and report it.
• Use equipment designed for site conditions and for the supply provided. Ask if you are not sure whether a tool is suitable.
• Make sure the supply is protected so that a fault cuts off power quickly. A residual current device is a common way to do this.
• Unplug tools before changing accessories or adjusting them.
• Keep cables off the ground where they can be crushed, cut or tripped over, and keep connections out of water.

Maintenance and inspection

Portable electrical equipment must be maintained so that it does not become dangerous. The Electricity at Work Regulations 1989 set no fixed inspection interval. Check the HSE electricity pages for the current guidance on maintaining portable equipment. As a user, your part is a quick visual check before use, and reporting anything wrong.

Competence

Only competent people should carry out work on electrical installations, including temporary supplies. A quick fix by someone who is not competent can create a hidden danger for the next person. If a socket, board or supply looks faulty, do not try to repair it. Tell your supervisor.

Buried cables and overhead lines

Two hazards cause serious incidents when they are overlooked.

Buried cables. Underground electrical cables can be struck by excavation work. Before digging, find out what is below the surface by checking available plans and records, and using suitable locating equipment as part of a safe system of work. Dig carefully, using hand tools to confirm the position of services where needed. Assume a cable could be live and do not rely on a plan being complete. HSE gives guidance on avoiding danger from underground services.

Overhead power lines. Plant, scaffolding, materials and long items can come into contact with overhead lines, or get close enough for electricity to arc across a gap. Know where the lines are before work begins and plan the work so that nobody and nothing gets too close. Never assume a line is dead. HSE guidance covers the precautions for working near overhead lines, so follow the site rules and the information your employer provides.

If a vehicle or object touches an overhead line, the situation is dangerous for everyone nearby. Stay clear, warn others and call the emergency services, as set out in your site emergency procedures.

Checklist before you use electrical equipment

Worked example: a temporary supply on a damp site

Consider a small site where a contractor sets up a temporary electrical supply for hand tools, and the ground is wet after rain. This is a general practice illustration, not an example taken from HSE or CITB.

1. Plan the supply. A competent person sets up the supply and the protective devices, because a poorly made temporary supply can create a hidden danger for everyone who uses it.
2. Choose the equipment. The tools and leads must be suitable for site conditions, including damp and mechanical damage, as the Electricity at Work Regulations 1989 require equipment to be fit for its environment.
3. Route the cables. Cables are kept off the ground where they could be crushed, cut or sit in water, and away from walkways.
4. Check before use. Each worker looks over the lead, plug and tool body before starting, and reports anything that looks wrong.
5. React to faults. When a cable is found cut, the tool is taken out of use and reported. Nobody covers the damage with tape.
6. Keep looking. The supervisor checks the arrangement again if conditions change, for example after more heavy rain or when plant is moved near the cables.

The example shows that electrical safety is not one check but a series of small habits and decisions, each supported by competent people.

Common questions on site

• Can I plug my tool into any socket I find? No. Use a supply that has been set up for site use and protected by a suitable device. If you are not sure, ask first.
• Can I repair a lead myself? If you are not competent to do the work, no. Take the item out of use and report it.
• What if I am not sure whether a cable is live? Treat it as live and keep clear until a competent person has made it safe.
• Who do I tell about a damaged socket or board? Your supervisor, as set out in your site procedures.

For more on equipment worn or used to protect you, see PPE on site. The hazard vs risk guide also helps with judging how serious an electrical problem is.

Practice check

These are original practice questions written for this site. They are not official CITB questions and do not predict your result. This site is independent and not affiliated with CSCS or CITB. To see how the real test is arranged, visit the operatives test format page.

Question 1. You notice that the outer cable of a power tool is cut and the wires are partly visible. What should you do?

• A. Wrap tape round the damage and carry on
• B. Use the tool only for short jobs
• C. Stop using it, take it out of use and report it
• D. Keep it but switch it on at the socket only when needed

Correct answer: C. Damaged equipment must not be used. Makeshift repairs do not make it safe.

Question 2. Before digging near a footpath you are told there may be buried services. What is the sensible approach?

• A. Start with a mechanical digger to save time
• B. Find out what is underground using plans and locating equipment, then dig with care
• C. Assume nothing is there if you cannot see it
• D. Dig only in the evening

Correct answer: B. Find out what is there first and dig with care, because a plan may be incomplete.

FAQ

Sources

• HSE: Electricity at work
• Legislation.gov.uk: Electricity at Work Regulations 1989

Independent guide, not affiliated with, authorised by, approved by or endorsed by CSCS or CITB. Last updated 2026-10-08.