Know Your Energy Sources: Critical Steps Before LOTO

Energy Control
English (NZ)

The Problem

Imagine diving into a pool without checking its depth—it might seem safe, but hidden dangers could prove fatal. The same applies when workers begin lockout/tagout (LOTO) procedures without fully identifying all energy sources. Hidden or incorrectly isolated energy can result in serious injuries or fatalities. Today, we’ll cover the critical steps for identifying and controlling all energy sources before beginning LOTO procedures.

Identify the Hazards

Electrical Energy Hazards:

  • Capacitors retaining residual electrical charge
  • Secondary or backup power supplies remaining energised
  • Stored energy in rectifiers or other components

Mechanical Energy Hazards:

  • Flywheels or cams continuing to move after shutdown
  • Tensioned springs releasing unexpectedly
  • Parts shifting and causing unintended movement

Pressure Systems Hazards:

  • Residual pressure trapped in valves and piping
  • Incorrect valve shutdown sequence causing retained energy
  • Incomplete bleeding of systems leading to sudden pressure release

Safety Practices and Preventative Measures

Review Written Procedures

  • Familiarise yourself with machine-specific procedures for isolating all energy sources
  • Confirm the correct sequence for isolating and releasing energy
  • Ensure clear testing procedures are documented and followed

Verify Training

  • Only undertake LOTO if you’ve had formal training on the specific equipment
  • Understand all energy sources and potential hazards
  • Be confident with all isolation and verification techniques

Conduct an Energy Assessment

  • Identify all energy types present—electrical, mechanical, hydraulic, pneumatic, etc.
  • Understand the magnitude of each source and how to isolate it
  • Recognise hidden dangers such as stored energy or secondary feeds

Test and Verify

  • After isolation, verify all energy has been controlled before commencing work
  • Use appropriate testing methods to ensure zero energy remains in the system

Real-Life Case or Scenario

Where possible, use an actual incident that you have experienced or been involved in.

On one site, a worker assumed a machine was de-energised after switching off the main power. However, a backup supply remained energised and caused unexpected movement of the equipment. The worker was severely injured. This incident could have been prevented with a complete energy assessment and verification process.

Employee Responsibilities

  • Understand all potential energy sources before starting LOTO

  • Always follow written LOTO procedures and confirm isolation is complete

  • Never begin work until all energy sources have been verified as controlled

  • Report any unclear or missing procedures to your supervisor

Employer Responsibilities

  • Provide written LOTO procedures for all plant with multiple energy sources

  • Ensure workers are trained in recognising and isolating various energy types

  • Supply appropriate tools and testing equipment

  • Maintain equipment and ensure compliance with WorkSafe NZ guidelines

Discussion & Questions

  • What hidden energy sources exist in our plant or equipment?

  • How do we verify complete isolation before work begins?

  • What challenges do we face when controlling multiple energy sources?

  • What improvements could be made to our LOTO procedures?

Commitment/Action Plan

Let’s commit to never starting LOTO until we’ve completed a thorough energy assessment and verification. Before every task, review the procedure, identify every energy source, and confirm full isolation.

Wrap-Up

Taking shortcuts with LOTO can lead to serious injury or worse. By understanding all energy sources, using correct isolation procedures, and verifying control, we can significantly reduce the risk of incidents. Thank you for committing to safe work practices and protecting yourself and your team.

Standards Overview

Under WorkSafe New Zealand’s guidance on energy isolation and LOTO, employers must:

  • Provide clear isolation procedures

  • Train workers on identifying and isolating all energy sources

  • Ensure verification processes are used before any maintenance or servicing

  • Maintain compliance with the Health and Safety at Work Act 2015 and related regulations

Disclaimer

These toolbox talks are provided for informational and educational purposes only and are not a substitute for professional legal, health and safety, or regulatory advice.

The content reflects recognised best practices and general industry standards as at the date of publication. However, it may not be applicable to all workplace environments or specific operational contexts.

It is the responsibility of the Person Conducting a Business or Undertaking (PCBU), as well as officers, workers, and other duty holders under the Health and Safety at Work Act 2015 (HSWA), to ensure compliance with all relevant laws, regulations, and WorkSafe New Zealand guidance.

The authors, presenters, and distributors of this toolbox talk disclaim all liability for any loss, damage, or injury arising from the use or reliance on the information provided. Users should seek advice from a suitably qualified health and safety professional or legal advisor for guidance tailored to their specific circumstances.

Always follow your organisation’s policies, procedures, and safe work practices to manage risks and maintain a safe and healthy workplace.

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Last Updated:
April 28, 2025