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.

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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

earth or PE 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.

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For measurement purposes, the Earth serves as a (reasonably)

constant potential reference against which other potentials can be measured.

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Earthing & Bonding specific to Static Electricity & Lightning

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Earthing is a practice where a static control system or lightning protection system is connected to an earth network such as an appropriate PE or Protective Earth or an independent earth network such as an SE or Static Earth (in the case of static electricity) or a dedicated LE Lightning Earth (in the case of a Lightning Protection system). Note that AS/NZS 3000 Section 5.8, suggests that static control or lightning protection systems should be connected to an independent earth network (SE or LE).

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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 static shock or discharge. The bonded items can then be connected

to a verifiable acceptable earth (PE/SE/LE at or below 10 ohms) to

bring them to Earth potential.

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Isolated metallic conductors that have not been bonded to a verifiable,

acceptable earth network (PE/SE/LE at or below 10 ohms)

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.

 

 

​Most static control equipment is required by the manufacturer to

be earthed and bonded to process and come with dedicated

earth posts/connectors for optimum performance as well as

minimizing stray discharges. 

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​The electrical earth installed by your electrician (PE or Protective Earth)

is there to protect the internal workings of the electrical system in your

building to accommodate everyday electricity usage. The PE 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 specifically  for static electricity. 

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​IT IS CRITICAL THAT YOU UNDERSTAND YOUR RESPONSIBILITY AS THE SITE

OWNER AND THE COMPLIANCE REQUIREMENTS AS SET OUT IN AS 1768:, 

AS/NZS 3000:,  AS/NZS 1020: & TS 60079-32-1:

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​HOW CAN WE HELP?

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​STATIC ELECTRICITY CONTROL & LIGHTNING PROTECTION

SYSTEMS ARE COMPLEX AND REQUIRE EXTENSIVE ENGINEERING AND DESIGN.

 

STATIC ELECTRICITY CONTROL PLAN & LIGHTNING PROTECTION PLAN

 

​IT  IS ALSO IMPORTANT TO MAINTAIN/REGULARLY TEST THE EARTH & BOND NETWORKS.

 

IF YOUR EARTH & BOND NETWORK IS ONE OF YOUR PRIMARY CONTROLS FOR EITHER STATIC ELECTRICITY OR LIGHTNING THEN IT IS CRITICAL THAT IT IS INSTALLED AND MAINTAINED CORRECTLY.

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