Proper Grounding and Bonding Techniques
The Problem
Improper earthing and bonding of electrical systems is a hidden danger on many New Zealand worksites. Without proper earthing, workers are at risk of electric shock, equipment failure, and even fire. Inadequate earthing is a leading cause of electrical incidents in construction. Today, we’ll focus on safe earthing and bonding practices to eliminate these hazards and ensure compliance with WorkSafe NZ standards.
Identify the Hazards
- Electric Shock: Occurs when earthing is faulty or missing, allowing current to pass through a person’s body.
- Arc Flash and Fires: Poor earthing can lead to electrical arcing, potentially resulting in fire or explosion.
- Equipment Damage: Ungrounded systems may short circuit, overheat, or become unstable.
- Electrocution in Wet Conditions: Without proper earthing, working in damp environments becomes especially dangerous.
Safety Practices and Preventative Measures
Understand the Basics:
- Earthing provides a safe path for electrical current to discharge into the ground in the event of a fault.
- Bonding ensures all conductive metal components are electrically connected to reduce the risk of voltage differences between them.
Inspect Earthing Systems:
- Regularly check earth rods, conductors, clamps, and connections for wear, corrosion, or disconnection.
- Test continuity between bonded components using appropriate testing tools.
Use Approved Materials:
- Use only certified earth conductors, clamps, and connectors that are fit for purpose.
- Do not use chains, uninsulated wires, or makeshift connections.
Verify Earthing for Temporary Systems:
- Ensure all temporary power systems (e.g., generators, site boxes) are earthed correctly.
- All temporary installations must meet AS/NZS 3012 (Electrical installations – Construction and demolition sites).
Protect Earthing Equipment:
- Route earth conductors away from traffic areas to avoid damage.
- Use covers or barriers when possible.
Work Safely in Wet Conditions:
- Wear insulated boots and gloves when working around electricity in wet areas.
- Confirm the earth connection is in place and tested before beginning work.
Real-Life Case or Scenario
On one site, a worker received a serious shock due to a corroded earth connection on a temporary power box. No testing had been done prior to use. A simple continuity check would have revealed the fault and prevented the incident.
Employee Responsibilities
- Test and visually inspect earthing and bonding systems before use.
- Use only certified and undamaged earthing materials.
- Report any damage or concern with electrical connections immediately.
- Never carry out makeshift repairs or adjustments—leave it to a registered electrician.
Employer Responsibilities
- Provide compliant and well-maintained earthing and bonding equipment.
- Ensure all temporary and permanent electrical systems meet AS/NZS 3000 (Wiring Rules) and AS/NZS 3012 standards.
- Train all workers in identifying and responding to electrical earthing hazards.
- Conduct regular inspections and testing of electrical systems.
Discussion & Questions
- “Have you come across poor earthing or bonding on-site before?”
- “What checks do you carry out to confirm safe electrical earthing before starting work?”
Encourage employees to share experiences or raise concerns about electrical safety and inspection practices.
Commitment/Action Plan
Let’s commit today to always inspecting and verifying earthing systems before starting any job involving electrical systems or equipment. Report all concerns immediately and never cut corners—electrical safety depends on us all.
Wrap-Up
Proper earthing and bonding are essential to electrical safety. By understanding these systems and applying safe work practices, we protect ourselves, our teammates, and our equipment. Thank you for your continued focus on safety.
Standards Overview
Under the Health and Safety at Work Act 2015 (HSWA), PCBUs must ensure electrical installations and systems are safe to use. Key references include:
- AS/NZS 3000 (Wiring Rules): Provides standards for safe design and installation of electrical systems, including earthing and bonding.
- AS/NZS 3012: Covers the safety of temporary electrical installations on construction and demolition sites.
- WorkSafe NZ’s Electrical Safety guidance highlights the need for proper testing, inspection, and maintenance of all electrical earthing systems.
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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