The stages of electrical lockout/tagout procedure

Electrical lockout is an essential procedure for ensuring the safety of workers when they carry out maintenance, repair or inspection work on electrical installations. It aims to eliminate any risk of electric shock or electrocution by ensuring complete control of energy sources. The various stages of electrical lockout must be followed to prevent the risk of electrocution and to comply with regulatory requirements and labour laws. 

This article details the steps involved in electrical lockout to help technicians, work supervisors, safety managers, and operators apply a reliable, traceable method that complies with standards.

Step 1: Shut down the installation

The first step in electrical lockout is to shut down the installation completely. This action must be carried out by an authorised person, usually an operations manager or lockout manager. It involves deliberately interrupting the operation of the equipment by activating the control devices provided for this purpose: emergency stop, local control, operational shutdown procedure, etc.

Before continuing with the procedure, it is essential to check that I have been switched off. This involves checking that the indicator lights are off, that the machines have stopped mechanically and that there are no characteristic operating noises. This phase prepares the entire system for physical separation, the first barrier against electrical risks.

Step 2: Physical separation

Once the installation has been shut down, the power sources must be physically separated. This step involves opening circuit breakers, disconnectors or switches and, if necessary, removing fuses in order to completely isolate the equipment or electrical panel. The objective is clear: to create a physical space between the installation and its power supply. This ensures that there is no possibility of current returning.

The authorised person performs this operation using the disconnecting devices designed to ensure visible and verifiable isolation. Physical separation is therefore a crucial step, as it eliminates the risk of accidental re-energisation. It must always be visually confirmed before proceeding with lockout.

Step 3: Lockout

Lockout is a measure designed to prevent any accidental or malicious operation of shut-off devices. It is carried out using dedicated lockout devices such as lockout padlocks, latches, locking clamps or multi-point systems. Each isolated device must be secured individually, and the user must identify each padlock to avoid any ambiguity.

Tagout plays a major role in this stage. A Tagout or standardised label must indicate the nature of the intervention, the name of the person who logged it and the date. The ultimate goal is to ensure effective protection against accidental reclassification before the intervention is complete.

Step 4: Checking for absence of voltage

Verification of absence of voltage is one of the most sensitive steps in electrical lockout. It must be carried out after locking out and before any contact with live parts. This verification must be carried out using a voltage absence verification device. This device complies with regulatory requirements and is governed by french standard NF C 18-510published by Afnor.

First, the procedure requires testing the device on a known source. Next, measurements are taken on the conductors concerned, and finally, the device is checked again. If no voltage is detected, the area is considered electrically safe. This step ensures that the separation is effective and that no residual voltage remains.

Step 5: Earthing and short-circuiting

Earthing and short-circuiting is an essential protective measure. It aims to discharge any accidental re-energisation that may occur on the installation. It protects workers against induced voltages, unexpected energy returns or upstream operating errors. This operation consists of connecting the conductors to a reliable earth connection using specially designed temporary earthing devices.

To be effective, earting and short-circuiting should be carried out as close as possible to the work area and on all active conductors. The equipment used must be in perfect condition and suitable for the voltage level of the installation. This step ensures maximum safety throughout the operation.

Monitoring and traceability of lockout stages: the role of Altsis’ Pégase solution

However, electrical logout/tagout procedure is not limited to technical actions: document tracking and traceability are just as essential. Each step, up to the end-of-work notification and power restoration, is logged in a dedicated register or software. This ensures compliance with standards and facilitates audits.

The Pégase solution offered by Altsis enables electrical network managers and, more generally, companies working in the electrical sector to centralise all data related to lockouts. This data covers a variety of elements : lists of locked-out equipment, intervention sheets, audit reports and maintenance histories. Thanks to its mobile application, it also offers immediate access to information in the field. This tool facilitates coordination between teams and ensures long-term security of the process through the use of collated messages.

The steps involved in electrical lockout : an essential procedure

The five steps of electrical lockout — shutdown, isolation, locking, verification of absence of voltage, and grounding — are essential to ensuring the safety of workers. In addition, consult the article dedicated to the Electrical Lockout Procedure to reinforce your best practices and overall understanding.