Isolation and tag-out procedures26 November 2020

Equipment that is offline for maintenance must be properly isolated from power, water, air and other sources to protect the safety of the people working on it, as well as the integrity of the process and equipment. But what are the essential steps in getting this right? By Brian Wall

All too often, people working on construction sites, and on refurbishment and maintenance activities, suffer electric shocks and burn injuries, some of which prove life-changing and sometimes fatal. “Electrical contractors should be aware that many of these accidents are a direct consequence of electricians not implementing safe isolation procedures of low-voltage installations [that is, those operating at up to 1,000V AC/1,500V DC],” cautions Martyn Allen, technical director of UK electrical safety experts Electrical Safety First, in the company’s best practice guide on the subject, produced in conjunction with the HSE (available via

“It’s vital that everyone in the industry adopts safe working practices and procedures, and it’s important that this is established right at the start of an electrician’s career. We undertake a range of activities to support best practice by the industry, including sponsoring free lockout kits to young electricians. In this way, we not only give them crucial safety equipment, we also hope to help them make safe working an ingrained habit. Because, as we know, it could mean the difference between life and death.”


Fortunately, such incidents are becoming increasingly rare. Figures collected by the Joint Industry Board on behalf of electrotechnical trade body ECA and Unite the Union reveal that, under RIDDOR (Reporting of Injuries, Diseases and Dangerous Occurrences Regulations), the rate of reportable accidents for electrical contractors has been falling ( No fatalities were reported during 2018 and the rate of specified (major) accidents was also lower than in 2017 at just over 52/100,000.

While greater awareness and practices across industry, along with tighter regulation, have played a major part in securing these improvements, the perils never go away. Hence, the introduction of the ‘Electricity at Work Regulations’ 1989, which require the isolation of electrical equipment and systems to prevent such dangerous occurrences (see also The regulations state that all electrical systems or equipment must be ‘DEAD’ before installation or maintenance is carried out: a system is any part of an electrical installation, from the source of supply to the equipment installed. The regulations also state that no person shall take part in any work activity, unless he/she possesses the necessary technical knowledge and experience to prevent danger or is under suitable supervision.

Electrical Safety First’s Allen also notes that, whatever the utility in question –power, water, air, gas – “one commonality is that those undertaking regular maintenance, or cleaning of the equipment or installation, must also be aware of the need for safe isolation”.


For many years, training provider JTL has offered apprenticeships in plumbing, as well as maintaining its electrical opportunities through professional short courses. It has also launched a number of initiatives, including free, bite-size digital courses through its new resource Power Up – including one focusing on isolation and tag-out procedures, with the company’s ‘An Introduction to Safe Isolation’ course offering clear guidance to apprentices and qualified electricians on best industry practices for safe working ( The course proposes seven stages of safe isolation, and introduces the legislation governing this process. It also pinpoints the potential risks that can be avoided by following up with additional tests and checks.

“The importance of following the safe isolation process correctly cannot be stressed enough,” says Ali Bullough, JTL technical trainer. “Failure to follow this process significantly increases risk of electric shock or fire, damage to the electrician, people in the area and the building, as well as its systems. Simply switching a circuit or distribution board off is not enough.”

She also references the stipulation in the Electricity at Work Regulations that systems be isolated and secured in the ‘off’ position to prevent inadvertent re-energising while they are being worked on. “Not verifying that the supply to a piece of equipment/circuit/distribution board is properly disconnected is also a dangerous thing to do.

“The supply may have been mislabelled or incorrectly wired; there could be dual supplies or timers in the circuits. As a result, the equipment could either still be live or re-energise while it is being worked on, and this could injure or kill the electrician. It is vital to note that, when verifying that a supply is dead, it is essential to test all live conductors against each other and all live conductors against earth.”

On a broader note, she points to how other trades follow their own processes for isolating supplies of gas, water and air, for example. “These include ensuring that the consumer’s side of the pipework remains connected to the main earthing terminal via a main protective bonding conductor. It is good practice to label a disconnected gas supply and, where it has been capped, it will need to be checked for leaks. When gas or water pipes are reconnected following work, pressure and tightness tests are conducted to ensure they are safe.”


“Isolating equipment (lockout) is only part of the story, though,” points out Alex Baker, safety business development manager at Spectrum Industrial. “Equally important is ‘tagout’, where a highly visible written warning is attached to the locked-out device, indicating that the equipment should not be used until the lockout is removed.”

For Spectrum Industrial, which provides solutions to help identify, manage and reduce safety risks and hazards in the workplace, ‘lockout-tagout’ (LOTO) go arm-in-arm to detail all of the steps necessary to ensure equipment energy is safety isolated. “The backbone of this is preparing a written LOTO policy and implementation plan, describing all processes required for a successful hazardous energy control programme,” he adds.

“The policy will cover responsibilities, training, isolation procedures and restoring equipment to normal operation, contractor control, LOTO products, permits to work and so on. Other steps include equipment appraisal and equipment-specific procedures, as well as training, procedure awareness and equipping authorised employees with the relevant lockout products and tags, as detailed in the audit.”

Padlocks are an essential part of a lockout tagout programme. “There are various types of keying systems that can be used as part of an effective LOTO programme. Choose the type that is suitable for the intended process, bearing in mind its place within the overall company lockout procedure.”

In addition to the tagout section is the ‘try-out’ element, LOTOTO (lockout tagout tryout), which is becoming increasing prevalent as best practice in high-risk industries, such as quarries, oil rigs, power stations, waste and heavy manufacturing. “Try-out creates an added safety measure by trying to turn back on a machine once isolated and operatives are in a safe position,” says Baker. “This either confirms a successful lockout, ready for the task commencement, and discounting any faults or potential stored energy that haven’t been otherwise relieved. Alternatively, it will highlight a problem where the operatives should then retreat from the task and record a near miss before an investigation is conducted.”

Brian Wall

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