WHAT IS EARTHING & BONDING?

 

...AND HOW CAN WE HELP?

 

WHAT IS EARTHING & BONDING?

 

In electrical engineering, ground (USA reference) or earth (Australian reference not to be confused with "Earth") is the reference point in an electrical circuit from which voltages are measured, a common return path for electric current, or a direct physical connection to the Earth.

Electrical circuits may be connected to ground (earth) for several reasons. In mains powered equipment, exposed metal parts are connected to ground (earth) to prevent user contact with dangerous voltage when electrical insulation fails. In electrical power distribution systems, a protective ground conductor is an essential part of the safety earthing system. Connection to ground (earth) also limits the build-up of static electricity when handling flammable products or electrostatic-sensitive devices.

For measurement purposes, the Earth serves as a (reasonably) constant potential reference against which other potentials can be measured.

EARTHING/BONDING AND LIGHTNING

Earthing is a practice where a lightning protection system is connected to an earth network or independent or functional earth network. Note that AS/NZS 3000 Section 5.8, suggests that static control or lightning protection systems should be on an independent functional earth network.

Bonding is the practice of intentionally electrically connecting metallic items not designed to carry electricity. This brings all the bonded items to the same electrical potential as a protection from electrical shock. The bonded items can then be connected to a verifiable acceptable earth to bring them to earth potential.

Isolated metallic conductors that have not been bonded to a verifiable, acceptable, independent earth network can build up an electrical charge. In the case of static electricity on a tanker truck , this could result in disastrous consequences. Isolated conductors such as metallic pipes entering a building can become a conduit for lightning.

 

 

 

 

 

 

 

The electrical earth installed by your electrician is there to protect the internal workings of the electrical system in your building to accommodate everyday electricity usage. The electrical earth is not designed to handle the mega electricity (100 million + volts of power or 200 kA of electrical energy) that a typical lightning strike can pack. It is also not designed for static electricity.

IT IS CRITICAL THAT YOU UNDERSTAND YOUR RESPONSIBILITY AS THE SITE OWNER AND THE COMPLIANCE REQUIREMENTS AS SET OUT IN AS/NZS 1768: 2007.

 

HOW CAN WE HELP?

TALK TO AN EXPERT. LIGHTNING PROTECTION SYSTEMS ARE COMPLEX AND REQUIRE EXTENSIVE ENGINEERING AND DESIGN.