Below – illustration showing a simple example of equipotential bonding.

Equipotential bonding – commonly referred to as bonding –  is a very important measure in reducing the risk of equipment damage and personal injury. Bonding involves joining together all metalwork and conductive items that are or may be earthed so that it is at the same potential (voltage) everywhere. If a component failure occurs, all circuits and conductors in a bonded area will have the same electrical potential, so that an occupant of the area cannot touch two objects with significantly different potentials. Even if the connection to a distant earth ground is lost, the occupant will be protected from dangerous potential differences resulting in injury or death from electric shock.

The earthng system is an important part of a lightning protection system. The structure of buildings often includes reinforcing bars, steel frames and deck slabs as the main components. These components can also be used to form a low impedance grounding system.

Earthing vs. Bonding

Earthing is intended to limit the duration of voltages, while bonding is intended to limit the magnitude of voltages. The danger of electric shock due to indirect contact arises from the following voltages which may occur under earth fault conditions in an installation:

  1. voltages between exposed conductive materials and other exposed conductive materials
  2. voltages between peripheral conductive materials and other peripheral conductive materials
  3. voltages between exposed conductive materials and peripheral conductive materials
  4. voltages between exposed conductive materials and Earth, or peripheral conductive materials and Earth.

The purpose of earthing, where used for protective purposes within a building or other facility, is to limit the duration of the voltages in the above examples. This is achieved by the operation of a protective device (such as a fuse or circuit-breaker) under earth fault conditions, which removes the voltages by causing an automatic disconnection of the supply to the faulty circuit.

Without an adequate earthing system in place, the protective device could not operate as required under earth fault conditions. In contrast, the purpose of bonding is to limit the magnitude of the voltages in examples 1, 2 and 3 above. This is achieved by electrically connecting (bonding) those conductive parts.


Bonding of services


Cadweld Exothermic Bonding


Bonding of services

Equipotential bonding is done from the switchboard (also known as the fuse box, breaker box, or distribution board) to incoming water and gas services. It is also done in bathrooms where all exposed metal that leaves the bathroom (including metal pipes and the earths of electrical circuits) must be bonded together to ensure that they are always at the same potential. Isolated conductive objects (including metal fittings fed by plastic pipe) do not need to be bonded.

In Australia, a house’s earth cables must be connected both to an earthing rod driven into the ground and also to the plumbing.

Earthing and bonding are an integral part of any modern electrical protection system. It is crucial in ensuring personnel safety, as well as providing reliable protection for vital equipment
and to minimise interruptions of service and costly down time.

The design at right identifies a typical grounding system and the components necessary for the job. However, this amounts to very little if the design is ineffective.

We don’t know where or when lightning will strike..

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About us

Lightning fatalities

Lightning is responsible for between 6 to 10 fatalities and over 100 injuries to Australians annually,

Lightning & Surge Technologies

specialist organization which strives to provide innovative and engineered solutions, which minimize

Distributor for ERICO

world leaders in Lightning and Surge Protection, we distribute their CRITEC range of high


Lightning & Surge Technologies

can provide a variety of services to help ensure that your business operations suffer the least amount of disruption and downtime due to lightning strikes, or power surges.

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To maintain the highest level of service and performance, Lightning & Surge Technologies collaborates with our friends at PhysElec Solutions Pty Ltd.

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There are a number of key areas that are focused on when conducting a site audit at a facility. We follow and work to a 6 point plan that allows us to methodically audit your facility. It is based on:

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We can provide Lightning Protection Design service to AS1768 “Rolling Sphere”, and “Collection Volume” methodology.

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We can provide Earthing Design Service and component calculations for use in Lightning Protection applications.

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AS1768 recommend that Lightning Protection Earthing systems are to be checked for compliance every 12 months, and that earth resistance is no greater than 10 ohms.

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Lightningman thunderbolt 2

System 3000

Solar Power

Strike guard


Lightningman LightningMat EPR Safety Mat

Electrical discharge events such as lightning strikes and electrical power system faults present serious electrocution hazards to any person in close proximity to the “Earth Potential Rise” (EPR) that accompanies such high potential events. It is widely estimated that 85% of all Lightning related injury and fatality statistics are attributed to this EPR condition, whilst outdoor workers represent one of the highest percentages within the lightning injury statistics.

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Lightningman LightningMat EPR Safety Mat

The purpose of this document is to provide a guide for personal safety during thunderstorms.

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Anticipating a Thunderstorm

Keep a constant lookout for thunderstorm clouds in the region. They can develop in as little as 15 minutes. If thunder is heard and

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Hazardous locations

Avoid these if possible:
• Explosives magazines
• Munitions storage

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