Your Complete Guide To Maintaining A Chainsaw

Maintaining a chainsaw

Proper maintenance is essential if a chainsaw is to be safe to use and will provide protection against ill health from excessive noise and vibration. Maintain the saw in accordance with the manufacturer’s recommendations with all the safety devices in efficient working order and all guards in place. It will need to be regularly serviced by someone who is competent to do so.

Operators need to be trained in the correct chain-sharpening techniques and chain and guide bar maintenance to keep the saw in safe working condition. Operators need to report any damage or excessive wear from daily checks on the following:

on/off switch;
chain brake;
chain catcher;
guide bar, drive sprocket and chain links;
side plate, front and rear hand guards;
anti-vibration mounts;
starting cord for correct tension.


Employers have duties concerning the provision and use of personal protective equipment (PPE) at work. PPE is equipment that will protect the user against health or safety risks at work. It can include items such as safety helmets, gloves, eye protection, high-visibility clothing, safety footwear, safety harnesses and respiratory protective equipment.

PPE should only be used as a last resort, ie when all other ways to eliminate or

reduce risks have been considered. When selecting PPE, make sure it’s CE marked and it suits the user in terms of

size, fit etc. If more than one item of PPE is worn at the same time, make sure they can be used together, eg wearing safety glasses may disturb the seal of a respirator, causing air leaks. Make sure that users of PPE are instructed and trained on its use and it is maintained and available at all times. Protective clothing complying with the appropriate standard should provide a consistent level of resistance to chainsaw cut-through. Other clothing worn with the PPE needs to be close fitting and non-snagging. Note: No protective equipment can ensure 100% protection against cutting by a hand-held chainsaw.

Relevant PPE standards:

Safety helmet to EN 397. It is recommended that arborists working from a rope and harness use a mountaineering style helmet. Hearing protection to EN 352-1. Eye protection: Mesh visors to EN 1731 or safety glasses to EN 166. Upper body protection: Chainsaw jackets to BS EN 381-11. Chainsaw jackets can provide additional protection where operators are at increased risk (eg trainees, unavoidable use of a chainsaw above chest height). However, this needs to be weighed against increased heat stress generated by physical exertion (eg working from a rope and harness). Gloves: The use of appropriate gloves is recommended under most circumstances. The type of glove will depend on a risk assessment of the task and machine. Consider the need for protection from cuts from the chainsaw, thorny material and cold/wet conditions. Where chainsaw gloves are required these need to be to EN 381-7.

Leg protection to EN 381-5. (All-round protection is recommended for arborists working in trees and occasional users, such as those working in agriculture.) Chainsaw boots to BS EN ISO 20345:2004 and bearing a shield depicting a chainsaw to show compliance with EN 381-3. (For occasional users working on even ground where there is little risk of tripping or snagging on undergrowth or brash, protective gaiters conforming to EN 381-9 may be worn in combination with steel-toe-capped safety boots.)

Lone workers

Lone workers should not be put at more risk than other employees. Think about and deal with any health and safety risks before people work alone. Consider the following:

whether there is a need to assess areas of risk including violence, manual handling, the medical suitability of the individual to work alone and any risks arising from the nature of the workplace itself;
whether there are any particular requirements for training and levels of experience needed;
what systems might be needed to supervise and keep in touch with lone workers where a risk assessment shows this is necessary. Avoid working alone with a chainsaw. Where this is not possible, make arrangements for raising the alarm if something goes wrong. These may include:
regular contact with others using either a radio or telephone;
someone regularly visiting the worksite;
carrying a whistle to raise the alarm;
an automatic signalling device which sends a signal at a preset time unless prevented from doing so;
checks to ensure operators return to base or home at an agreed time.

You are responsible for making sure your employees receive immediate attention if taken ill or injured at work. Your arrangements will depend on the particular circumstances in your workplace and you need to assess what your first-aid needs are. As a minimum, you must have:

a suitably stocked first-aid box;
an appointed person to take charge of first-aid arrangements;
information for all employees giving details of first-aid arrangements.

You might decide that you need a first-aider, ie someone trained by an approved organisation, and who holds a qualification in first aid at work or emergency first aid at work.There is no legal requirement for operators to hold an emergency first-aid at work certificate but we recommend they do so. Anyone working with chainsaws needs

to be trained in emergency first aid, and in particular how to control major bleeding and deal with crush injuries. In remote sites, people who have been injured may also be at risk of hypothermia. Make sure operators always carry a personal first aid kit (incorporating a large wound dressing) with them and have reasonable access to a more comprehensive kit.

Working with chainsaws-Fuelling and lubrication

Make sure petrol containers are in good condition, clearly labelled, and provided with securely fitting caps. Use containers specially designed for chainsaw fuelling and lubrication. Fit an auto-filler spout to the outlet of a petrol container to reduce the risk of spillage from over-filling. Operators need to:

avoid getting dirt in the fuel system (this may cause the chainsaw to be unreliable);
securely replace all filler caps immediately after fuelling/oiling;
wipe up any spilt petrol/oil;
keep fuel containers well away from fires and other sources of ignition, including the saw itself (at least 4 m is recommended) during starting and use.

Do not allow operators to use discarded engine oil as a chain lubricant – it is a very poor lubricant and may cause cancer if it is in regular contact with an operator’s skin. Starting the chainsaw and pre-use checks When preparing to use a chainsaw, operators need to check:

all nuts, screws etc are tight;
the saw chain is correctly tensioned;
the throttle cannot be squeezed unless the throttle lock-out is pressed;
they are wearing the correct PPE.

When starting the saw, operators need to maintain a safe working distance from other people and ensure the saw chain is clear of obstructions. When starting a chainsaw with a cold engine, operators need to:

place the saw on level ground;
secure the saw firmly, eg put a foot on the rear-handle base plate and a hand on the front handle;
set the controls as recommended by the manufacturer;
pull the starter cord firmly. Once the saw has started, operators need to rev the throttle to warm up the engine and check that:
the saw chain stops moving when the engine revs return to idle;
the chain brake is effective when applied at maximum revs or according to the manufacturer’s specification;
the engine continues to run when the saw is turned through 90° in any direction;
the stop switch works correctly;
lubrication to the guide bar and chain is working properly.

These checks need to be repeated at regular intervals throughout the day. When starting a chainsaw with a hot engine, operators may use the same method as above. Alternatively, they can grip the rear handle firmly between the knees and the front handle with their left hand, pulling the starter with their right hand. Once the saw is running, operators should apply the chain brake before moving off with the saw. Most modern chainsaws will allow hot starting with the chain brake applied.


Kickback is the sudden uncontrolled upward and backward movement of the chain and guide bar towards the operator. This can happen when the saw chain at the nose of the guide bar hits an object. Kickback is responsible for a significant proportion of chainsaw injuries, many of which are to the face and parts of the upper body where it is difficult to provide protection. A properly maintained chain brake and use of low-kickback chains (safety chains) reduces the effect, but cannot entirely prevent it. Make sure operators use the saw in a way which avoids

kickback by:

not allowing the nose of the guide bar to accidentally come into contact with any obstruction, eg branches, logs, stumps;
not over-reaching;
keeping the saw below chest height;
keeping the thumb of the left hand around the back of the front handle;
using the appropriate chain speed for the material being cut.

Using the chainsaw

Whatever the job, check the worksite thoroughly to identify any potential hazards. This is particularly important when carrying out felling or demolition work. Wherever possible, maintain a clear working area on the site. For any work with a chainsaw ensure:

the risks from the work have been assessed and controlled;
the operator is competent to do the job;
the operator wears the appropriate PPE;
the operator either stops the engine or applies the chain brake when not cutting with the saw.

Manual handling

Manual handling causes over a third of all workplace injuries. These include work-related musculoskeletal disorders (MSDs) such as upper and lower limb pain/disorders, and joint and repetitive strain injuries of various sorts. Manual handling covers a wide variety of tasks including lifting, lowering, pushing, pulling and carrying. If any of these tasks are not carried out appropriately, there is a risk of injury.

Manual handling injuries can have serious implications for both the employer and the person who has been injured. They can occur almost anywhere in the workplace and heavy manual labour, awkward postures and previous or existing injury can increase the risk. To help prevent manual handling injuries in the workplace, you should avoid such tasks as far as possible. However, where it is not possible to avoid handling a load, employers must look at the risks of that task and put sensible health and safety measures in place to prevent and avoid injury, using lifting aids where necessary. These simple rules will help operators:

only lift when it is really necessary;
only lift loads well within their capability;
don’t lift with the back bent, stretched or twisted;
always keep loads close to the body;
get help if they need it;
give themselves proper rest breaks.

Aid tools

Operators will find it a lot easier to follow these rules if you invest in a few simple bits of equipment such as pulp hooks, log tongs and high lift wedges. Used correctly they will help operators to do the job with a minimum of effort and with a straight back. Correct body position Whether on the ground or up a tree, it is vital that forces on the back are applied evenly. Before lifting, operators should take up a position which gives secure footing and doesn’t force them into an awkward posture. Place the feet apart with one leg slightly forward to keep balanced. If operators are levering over a tree, moving pieces of timber, or just picking up a chainsaw – the best way to do it is with bent knees, straight back and with the load as close to the body as possible.

That way they are lifting with their strong leg muscles, rather than their back. Operators should not lever over a tree with one hand pushing on the tree and one on the lever. The back will be stretched and twisted, and most of the load will be taken by the lower back muscles. It is very important that operators have a good grip when lifting and are free to adjust their position for the best lift. One of the best methods is to use properly sharpened pulp hooks or log tongs. This will also preserve their gloves and they won’t have to bend so far. They should use both hands, otherwise they will tend to twist their back. A log pick can also be a useful handling tool in some situations.

Using a chainsaw

Operators may not think of their chainsaw as a load – but it is! If they work in a stooped position, with the weight of the saw hanging from their arms, the strain on their back will be considerable. When operators are making the felling cut on a tree, they can support the weight of the saw by bracing their forearms on their thighs or knees. Resting the saw on the thigh when crosscutting and debranching takes the weight off the lower back muscles.

Operators should keep close to the saw – this will also reduce the risk of kick-back. They should aim to work at a height where they can easily support the saw on the tree without stooping.

Handling timber

Operators should cut the timber into manageable pieces, getting someone to help them with the larger sections. They can often avoid having to lift by rolling, pivoting or sliding the wood. The more thought put into felling and processing the trees, the easier this will be. Aid tools will help operators do the job safely. If they do have to carry timber, they should make sure the ground is free of obstacles and tripping hazards.

Heavy loads

Even good lifting techniques have their limitations when it comes to heavy loads. Wherever possible operators should use equipment which gives their body a big advantage. A portable winch is useful for applying large forces when felling large or awkward trees. It will also make it easier to turn over a large tree stem. Similarly high

lift wedges allow operators to apply forces well in excess of those from a breaking bar – their use will spare operators’ backs and give them much more control. Felling cushions are also available which can be used instead of wedges. Exhaust gas from the chainsaw is used to inflate the cushion and force the tree over. For some jobs, let a machine take the strain.

Correct manual handling is part of doing the job properly. Recognised training courses are available for chainsaw work and for some other tasks involving timber handling. These will teach operators how to do the job safely and efficiently without putting their back at risk. Before felling starts on the worksite:

contact the owners of any overhead power lines within a distance equal to twice the height of any tree to be felled to discuss whether the lines need to be lowered or made dead;
do not start work until you have reached agreement on the precautions to take;
check whether there are underground services such as power cables or gas pipes which could be damaged when the tree strikes the ground;
if there are roads or public rights of way within a distance equal to twice the height of the tree to be felled, ensure that road users and members of the public do not enter the danger zone. You may need to arrange warning notices, diversions or traffic control.

When felling a tree:

check if it is affected by rot;
assess what could affect the direction of fall, such as wind conditions and whether the tree is leaning, has uneven growth or branches which could foul other trees;
be especially careful to check for broken crowns and branches which might fall during the operation;
check both the tree to be felled and those nearby;
operators may need to use aid tools such as alloy or plastic wedges, a breaking bar, a can’t hook, a winch, or high-lift wedges and a sledgehammer;
make sure operators have the right equipment available and the skills to use it correctly.

If a tree is or is likely to become hung up on another during felling, operators will need to have the knowledge and the equipment to bring it down safely. Dealing with leaning trees or wind-blown trees also requires special skills.

How To Carry Out An Effective Ariel Tree Rescue

The Rescue Operation

This article covers the safe working practices to be used by those involved in aerial tree rescue, a minimum of two people should be present during all tree-climbing operations. One of the ground team must be available, competent and equipped to perform an aerial rescue without delay. Ensure a designated and responsible person knows the daily work programme and agree with them a suitable contact procedure. Where reasonably practicable, use a two-way radio or mobile phone and a pre-arranged call-in system. This is particularly important for remote sites where a check on the operator’s safety is important.

Before the rescue

The worksite

As part of the risk assessment, the worksite and planned operation must be evaluated to establish the necessary emergency procedures for recovery and evacuation of casualties. All operators on site should have received adequate instruction and information and be trained in these procedures. When an injured climber needs rescuing, ensure all possible precautions are taken to safeguard other members of the work team and any other people entering or approaching the worksite. If overhead cables are involved, do not approach the work area. Stop work, assess the situation and contact the relevant electricity company. Ensure no unauthorised people are within the work area.

The casualty

The casualty’s condition must be assessed. If necessary, call for the emergency services before starting the rescue, making sure you give appropriate information about the location of the site and any particular access problems. You will need to provide personal details about the casualty (names and any relevant medical history etc), as well as the approximate time of the accident, treatment given and any chemicals involved.

Rescue equipment

The following rescue equipment needs to be available at the worksite:

A suitable first-aid kit.
A suitable climber’s harness and associated equipment, eg ropes, strops, karabiners or any other equipment that the rescuer is familiar with to help their rescue technique.
Other items of equipment necessary for a rescuer to climb effectively, eg a ladder, climbing irons, ascenders or descenders.
A sharp knife with a retractable blade for cutting ropes etc. There is a risk of recoil when cutting ropes under tension, or cutting the wrong rope, as well as cut injuries to the rescuer or casualty. Consider other techniques for removing a casualty from a tensioned line.

Send for any additional rescue equipment that becomes necessary but is not available at the rescue site. If appropriate, other people in the vicinity may be directed to provide help.

The rescue

Helping the casualty

Reassure the casualty and encourage self-help whenever possible. Select a rescue method that does not put the rescuer at risk and minimises the risk of further injury to the casualty. Only trained operators should use equipment such as mobile elevated work platforms and cranes for an aerial tree rescue. Climbing to the casualty

Select an efficient method of climbing the tree to reach the casualty as quickly as possible.

If specialised climbing aids are available and rescue personnel are trained in their use, use them to speed up access to the casualty. Take account of hazards such as severed, broken or hanging branches, or the casualty’s equipment, that may create a risk.

Assess the tree(s) and select appropriate equipment to remove parts of the tree(s) that would impede the rescue operation. Other operators may do this if needed. Use other personnel, if available, to prepare the equipment ready for use in the tree(s). Make the area safe from immediate hazards as soon as possible. Assess the casualty’s condition and prioritise first-aid treatment. In some cases, especially those involving fracture, crush or possible spinal injury, only move the casualty under medical supervision (eg a paramedic or the ambulance service).

Descending with the casualty

The rescuer needs to maintain close contact with the casualty to monitor changes in condition and to calm and control them if necessary. Rescuers should be properly anchored at all times to ensure their own safety throughout the rescue operation. Anchor points must be selected to ensure they are capable of taking the anticipated loads during the rescue. The rescuer and casualty need to descend together to ease movement through the branches and to monitor the casualty’s condition. Densely branched trees may require alternative methods of rescue. Obstacles on the ground may dictate the most suitable method.

Completing the rescue

Continue to help the casualty under the direction of paramedics until the casualty is transported from the site. Ensure the site is safe and secure before all personnel leave. Note the contact details of any witnesses. Where possible, take photographs of the site. Do not use any of the equipment involved in the incident until it has been thoroughly examined by a competent person. Notify management of the incident and record the occurrence in the accident book.

The Dangers Of Overhead Power Lines Best Practices


Every year people at work are killed or seriously injured when they come into contact with live overhead electricity power lines. These incidents often involve:

machinery, eg cranes, lorry-loader cranes, combine harvesters, and tipping trailers;
equipment, eg scaffold tubes and ladders;
work activities, eg loading, unloading, lifting, spraying, and stacking.

If a machine, scaffold tube, ladder, or even a jet of water touches or gets too close to an overhead wire, then electricity will be conducted to earth. This can cause a fire or explosion and electric shock and burn injuries to anyone touching the machine or equipment. An overhead wire does not need to be touched to cause serious injury or death as electricity can jump, or arc, across small gaps.

One of the biggest problems is that people simply do not notice overhead lines when they are tired, rushing or cutting corners. They can be difficult to spot, eg in foggy or dull conditions, when they blend into the surroundings at the edge of woodland, or when they are running parallel to, or under, other lines. Always assume that a power line is live unless and until the owner of the line has confirmed that it is dead. This guidance is for people who may be planning to work near overhead lines

where there is a risk of contact with the wires, and describes the steps you should take to prevent contact with them. It is primarily aimed at employers and employees who are supervising or in control of work near live overhead lines, but it will also be useful for those who are carrying out the work.

Types of overhead power lines

Most overhead lines have wires supported on metal towers/pylons or wooden poles – they are often called ‘transmission lines’ or ‘distribution lines’. Most high-voltage overhead lines, ie greater than 1000 V (1000 V = 1 kV) have wires that are bare and uninsulated but some have wires with a light plastic covering or coating. All high-voltage lines should be treated as though they are uninsulated. While many low-voltage overhead lines (ie less than 1 kV) have bare uninsulated wires, some have wires covered with insulating material. However, this insulation can sometimes be in poor condition or, with some older lines, it may not act as effective insulation; in these cases you should treat the line in the same way as an uninsulated line. If in any doubt, you should take a precautionary approach and consult the owner of the line.

There is a legal minimum height for overhead lines which varies according to the voltage carried. Generally, the higher the voltage, the higher the wires will need to be above ground. Equipment such as transformers and fuses attached to wooden poles and other types of supports will often be below these heights. There are also recommended minimum clearances published by the Energy Networks Association.

What does the law require?

The law requires that work may be carried out in close proximity to live overhead lines only when there is no alternative and only when the risks are acceptable and can be properly controlled. You should use this guidance to prepare a risk assessment that is specific to the site. Businesses and employees who work near to an overhead line must manage the risks. Overhead line owners have a duty to minimise the risks from their lines and, when consulted, advise others on how to control the risks. The line owner will usually be an electricity company, known as a transmission or distribution network operator, but could also be another type of organisation, eg Network Rail, or a local owner, eg the operator of a caravan park.

Preventing overhead line contact

Good management, planning and consultation with interested parties before and during any work close to overhead lines will reduce the risk of accidents. This applies whatever type of work is being planned or undertaken, even if the work is temporary or of short duration. You should manage the risks if you intend to work within a distance of 10 m, measured at ground level horizontally from below the nearest wire.

Remove the risk, the most effective way to prevent contact with overhead lines is by not carrying out work where there is a risk of contact with, or close approach to, the wires. Avoiding danger from overhead power lines. If you cannot avoid working near an overhead line and there is a risk of contact or close approach to the wires, you should consult its owner to find out if the line can be permanently diverted away from the work area or replaced with underground cables. This will often be inappropriate for infrequent, short-duration or transitory work. If this cannot be done and there remains a risk of contact or close approach to the wires, find out if the overhead line can be temporarily switched off while the work is being done. The owner of the line will need time to consider and act upon these types of requests and may levy a charge for any work done.

Risk control

If the overhead line cannot be diverted or switched off, and there is no alternative to carrying out the work near it, you will need to think about how the work can be done safely. If it cannot be done safely, it should not be done at all. Your site-specific risk assessment will inform the decision. Things to consider as part of your risk assessment include:

the voltage and height above ground of the wires. Their height should be measured by a suitably trained person using non-contact measuring devices;
the nature of the work and whether it will be carried out close to or underneath the overhead line, including whether access is needed underneath the wires;
the size and reach of any machinery or equipment to be used near the overhead line;
the safe clearance distance needed between the wires and the machinery or equipment and any structures being erected. If in any doubt, the overhead line’s owner will be able to advise you on safe clearance distances;the site conditions, eg undulating terrain may affect stability of plant etc;
the competence, supervision and training of people working at the site.

If the line can only be switched off for short periods, schedule the passage of tall plant and, as far as is possible, other work around the line for those times. Do not store or stack items so close to overhead lines that the safety clearances can be infringed by people standing on them.

Working near but not underneath overhead lines – the use of barriers. Where there will be no work or passage of machinery or equipment under the line, you can reduce the risk of accidental contact by erecting ground-level barriers to establish a safety zone to keep people and machinery away from the wires. This area should not be used to store materials or machinery. Suitable barriers can be constructed out of large steel drums filled with rubble, concrete blocks, wire fence earthed at both ends, or earth banks marked with posts.

If steel drums are used, highlight them by painting them with, for example, red and white horizontal stripes.
If a wire fence is used, put red and white flags on the fence wire.
Make sure the barriers can be seen at night, perhaps by using white or fluorescent paint or attaching reflective strips.

Avoiding danger from overhead power lines

The safety zone should extend 6 m horizontally from the nearest wire on either side of the overhead line. You may need to increase this width on the advice of the line owner or to allow for the possibility of a jib or other moving part encroaching into the safety zone. It may be possible to reduce the width of the safety zone but you will need to make sure that there is no possibility of encroachment into the safe clearance distances in your risk assessment.

Where plant such as a crane is operating in the area, additional high-level indication should be erected to warn the operators. A line of coloured plastic flags or ‘bunting’ mounted 3-6 m above ground level over the barriers is suitable. Take care when erecting bunting and flags to avoid contact or approach near the wires. Passing underneath overhead lines, if equipment or machinery capable of breaching the safety clearance distance has to pass underneath the overhead line, you will need to create a passageway through the barriers, In this situation:

keep the number of passageways to a minimum;
define the route of the passageway using fences and erect goalposts at each end to act as gateways using a rigid, non-conducting material, eg timber or plastic pipe, for the goalposts, highlighted with, for example, red and white stripes;
if the passageway is too wide to be spanned by a rigid non-conducting goalpost, you may have to use tensioned steel wire, earthed at each end, or plastic ropes with bunting attached. These should be positioned further away from the overhead line to prevent them being stretched and the safety clearances being reduced by plant moving towards the line;
ensure the surface of the passageway is levelled, formed-up and well maintained to prevent undue tilting or bouncing of the equipment;
put warning notices at either side of the passageway, on or near the goalposts and on approaches to the crossing giving the crossbar clearance height and instructing drivers to lower jibs, booms, tipper bodies etc and to keep below this height while crossing;
you may need to illuminate the notices and crossbar at night, or in poor weather conditions, to make sure they are visible;
make sure that the barriers and goalposts are maintained.

Avoiding danger from overhead power lines

On a construction site, the use of goalpost-controlled crossing points will generally apply to all plant movements under the overhead line. Working underneath overhead lines. Where work has to be carried out close to or underneath overhead lines, eg road works, pipe laying, grass cutting, farming, and erection of structures, and there is no risk of accidental contact or safe clearance distances being breached, no further precautionary measures are required. However, your risk assessment must take into account any situations that could lead to danger from the overhead wires. For example, consider whether someone may need to stand on top of a machine or scaffold platform and lift a long item above their head, or if the combined height of a load on a low lorry breaches the safe clearance distance. If this type of situation could exist, you will need to take precautionary measures.

If you cannot avoid transitory or short-duration, ground-level work where there is a risk of contact from, for example, the upward movement of cranes or tipper trailers or people carrying tools and equipment, you should carefully assess the risks and precautionary measures. Find out if the overhead line can be switched off for the duration of the work. If this cannot be done:

refer to the Energy Networks Association (ENA) publication Look Out Look Up! A Guide to the Safe Use of Mechanical Plant in the Vicinity of Electricity Overhead Lines.2 This advises establishing exclusion zones around the line and any other equipment that may be fitted to the pole or pylon. The minimum extent of these zones varies according to the voltage of the line, as follows:
– low-voltage line – 1 m;
– 11 kV and 33 kV lines – 3 m;
– 132 kV line – 6 m;
– 275 kV and 400 kV lines – 7 m;
under no circumstances must any part of plant or equipment such as ladders, poles and hand tools be able to encroach within these zones. Allow for uncertainty in measuring the distances and for the possibility of unexpected movement of the equipment due, for example, to wind conditions;
carry long objects horizontally and close to the ground and position vehicles so that no part can reach into the exclusion zone, even when fully extended. Machinery such as cranes and excavators should be modified by adding physical restraints to prevent them reaching into the exclusion zone. Note that insulating guards and/or proximity warning devices fitted to the plant without other safety precautions are not adequate protection on their own;
make sure that workers, including any contractors, understand the risks and are provided with instructions about the risk prevention measures;
arrange for the work to be directly supervised by someone who is familiar with the risks and can make sure that the required safety precautions are observed;
if you are in any doubt about the use of exclusion zones or how to interpret the ENA document, you should consult the owner of the overhead line.

Where buildings or structures are to be erected close to or underneath an overhead line, the risk of contact is increased because of the higher likelihood of safety clearances being breached. This applies to the erection of permanent structures and temporary ones such as polytunnels, tents, marquees, flagpoles, rugby posts, telescopic aerials etc. In many respects these temporary structures pose a higher risk because the work frequently involves manipulating long conducting objects by hand.

Avoiding danger from overhead power lines. The overhead line owner will be able to advise on the separation between the line and structures, for example buildings using published standards such as ENA Technical Specification 43-8 Overhead Line Clearances.1 However, you will need to take precautions during the erection of the structure. Consider erecting a horizontal barrier of timber or other insulating material beneath the overhead line to form a roof over the construction area – in some cases an earthed, steel net could be used. This should be carried out only with the agreement of the overhead line owner, who may need to switch off the line temporarily for the barrier to be erected and dismantled safely.

Ideally, work should not take place close to or under an overhead line during darkness or poor visibility conditions. Dazzle from portable or vehicle lighting can obscure rather than show up power lines. Sometimes, work needs to be carried out near uninsulated low-voltage overhead wires, or near wires covered with a material that does not provide effective insulation, connected to a building. Examples of such work are window cleaning, external painting or short-term construction work. If it is not possible to re-route or have the supply turned off, the line’s owner, eg the distribution network operator, may be able to fit temporary insulating shrouds to the wires, for which a charge may be levied. People, plant and materials still need to be kept away from the lines.

Emergency procedures

If someone or something comes into contact with an overhead line, it is important that everyone involved knows what action to take to reduce the risk of anyone sustaining an electric shock or burn injuries. Key points are:

never touch the overhead line’s wires;
assume that the wires are live, even if they are not arcing or sparking, or if they
otherwise appear to be dead;
remember that, even if lines are dead, they may be switched back on either automatically after a few seconds or remotely after a few minutes or even hours if the line’s owner is not aware that their line has been damaged:
if you can, call the emergency services. Give them your location, tell them what has happened and that electricity wires are involved, and ask them to contact the line’s owner:
if you are in contact with, or close to, a damaged wire, move away as quickly as possible and stay away until the line’s owner advises that the situation has been made safe:
if you are in a vehicle that has touched a wire, either stay in the vehicle or, if you need to get out, jump out of it as far as you can. Do not touch the vehicle while standing on the ground. Do not return to the vehicle until it has been confirmed that it is safe to do so;

Avoiding danger from overhead power lines, be aware that if a live wire is touching the ground the area around it may be live. Keep a safe distance away from the wire or anything else it may be touching and keep others away.