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Topic: Earthing system

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In the News (Sat 20 Apr 19)

  Earthing system at VK1OD
Earthing is the system of connections to the general mass of earth.
Earth systems that are intended to form part of an RF radiating system (antenna) have different requirements to a protective earth system of a power distribution system or earthing for lightning discharge.
Measurements of the earth resistance of the 1.2m electrode approach 100 ohms after prolonged dry spells, so an extension of 1.4m was joined using a brass coupler and the combination driven to a depth of 2.6m, which at the time of driving reduced earth resistance from 75 ohms to 24 ohms.
www.vk1od.net /post/earthing.htm   (1981 words)

Earthing of electrical systems is required for a number of reasons, principally to ensure the safety of people near the system and to prevent damage to the system itself in the event of a fault.
The resistance of the earth path must be low enough so that the potential rise on the earth terminal and any metalwork connected to it is not hazardous; a value of 50 volts is often quoted, but some locations and circumstances require a lower limit.
The primary purposes of the earthing system of a building are to ensure that a safe environment is maintained for the occupants and to protect equipment from damage in the event of a fault.
www.cda.org.uk /megab2/elecapps/pub123/sec5.htm   (1710 words)

 Make A Well-Grounded (Earthed) Fence
Most farms seem to have earth systems which can't cope with the flow of electrons coming back to it from fences with poor insulation, leakage into vegetation, and the occasional wire which breaks and touches the ground or touches a non-insulated wire.
An inadequate earth system reduces the output of your energiser and increases the chances of shocks in milking parlors, yards and water troughs.
To avoid this, earth systems should be in a damp area well to the side of the milking parlor, or even have earth pipes well to both sides, but never in line with the parlor.
www.ibiblio.org /farming-connection/grazing/features/ground.htm   (3375 words)

 3.4 Code of Practice requirements
The earthing systems should be designed and installed to prevent any significant portion of the high voltage system voltage gradient being superimposed on the low voltage earthing system and as a result, transferred to the customer’s electrical installation through the MEN system.
When the two earthing systems are located where a person may make contact between the earthed exposed conductive parts or conductors connected to the earthing systems, adequate separation or insulation should be provided between the exposed conductive parts or conductors or both.
Where the two earthing systems are located so that personal contact may be made between the earthed exposed conductive parts or conductors connected to the earthing systems, adequate separation or insulation should be provided between the exposed conductive parts or conductors or both.
www.dir.qld.gov.au /electricalsafety/law/codes/works/earthing/requirement/index.htm   (1772 words)

 [No title]
I - indicates either that the supply system is not earthed at all, or that the earthing includes a deliberately-inserted impedance, the purpose of which is to limit fault current.
Protective conductor systems against lightning need to be connected to the installation earthing system to prevent dangerous potential differences.
Where a functional earthing system is in use, the protective requirements of the earthing will take precedence over the functional requirements.
www.tlc-direct.co.uk /Book/5.2.1.htm   (252 words)

Earthing of electrical networks and installations is important to ensure correct operation.
The general installation and design aspects for the earth electrode are similar throughout these applications, although the overall earthing system design will differ significantly amongst them.
Its successful application is reinforced in standards, such as BS 7430, ‘Code of Practice for Earthing’, which states "Copper is one of the better and commonly used materials for earth electrodes and underground conductors" In fact, some standards forbid the use of many other metals for this purpose - especially for the buried earth electrode.
www.cda.org.uk /megab2/elecapps/earthing/index.htm   (531 words)

 Copper Earthing System
Earth rods are commonly made from solid copper or stainless steel with copper bonding.
When a lightning protection system is struck, its electrical protection with respect to earth is significantly raised and if resistance offered by the down conductor becomes more then the other metalwork on the structure, the discharge seeks alternative path to earth by side flashing.
Earthing is the electrical drain path for stray energy in an electrical circuit.
www.mehtatubes.com /copperearthingsystem.html   (755 words)

 5.1.8 EARTHING AND EQUIPOTENTIAL BONDING   (Site not responding. Last check: 2007-10-13)
Note that earthing does not necessarily prevent anyone receiving a shock, but together with the time/current characteristics of the protective device (fuse, MCB or RCD) it should ensure that it is not lethal.
The bare tails of earth conductors must be insulated with green/yellow sleeving from the exit from the cable sheath to the earth terminal.
All metal boxes should be connected to the earth; either through a short tail covered with green/yellow sleeving to the socket earth terminal or directly by the earth conductor for a switch box.
www.borpin.co.uk /sbfaq/faq51172.htm   (1307 words)

 Grounding vs Bonding Part 2 of 12
Another function of this earthing is to “stabilize the voltage to earth during normal operation” by providing a common reference point.
In a grounded system, the supply transformer secondary windings may be wye-configured with the center tap grounded or it may be delta-configured with a corner grounded.
The lower the resistance of the utility grounding (earthing) system, the lower the secondary voltage surge.
www.ecmweb.com /mag/electric_grounding_vs_bonding_2/index.html   (1323 words)

 Earthing   (Site not responding. Last check: 2007-10-13)
T = Earth (from the French word Terre) N = Neutral S = Separate C = Combined I = Isolated (The source of a IT system is either connected to Earth through a deliberately introduced earthing impedance or is isolated from Earth.
This is because TN-C requires an exemption from the Electricity Safety, Quality and Continuity Regulations, and an IT system is not permitted for a low voltage public supply in the UK because the source is not directly earthed.
A TN-S system, shown in figure 1, has the neutral of the source of energy connected with earth at one point only, at or as near as is reasonably practicable to the source, and the consumer’s earthing terminal is typically connected to the metallic sheath or armour of the distributor’s service cable into the premises.
www.gadsolutions.biz /electrical-data/earthing.html   (283 words)

System earthing is essential to the proper operation of the system, whereas equipment earthing concerns the safety of personnel and plant.
A key function of equipment earthing is to provide a controlled method to prevent the build up of static electricity, thus reducing the risk of electrical discharge in potentially hazardous environments.
Part 1, section requires that delivery vehicles are earthed by use of a connecting lead to the earthing point of the fixed installation or by provision of a vehicle earth tread plate and/or a connecting lead to the vessel bonding connection.
www.hse.gov.uk /comah/sragtech/techmeasearthing.htm   (2063 words)

The potential increases on the earthing and on all earthed metal parts of the object relative to the zero potential at a distant point.
The objective of the earth electrode subsystem is to reduce ac and dc potentials between and within equipment.
"Systems and circuit conductors are grounded to limit voltages due to lightning, line surges, or unintentional contact with high voltage lines, and to stabilize the voltage to ground during normal operation.
www.lightningsafety.com /nlsi_lhm/rtaf3_recomended_ground_guide.html   (1187 words)

 System earthings in LV   (Site not responding. Last check: 2007-10-13)
System earthings in LV System earthings in LV This «Cahier Technique» proposes a survey of potential hazards that insulation faults may create for safety of persons and property.
It presents the three most common system earthings defined in standard IEC 60364 and used to varying degrees in all countries.
All system earthings are equivalent as far as safety of persons is concerned, but each system earthing has its own advantages and disadvantages regarding the operation of electrical installation.
www.schneider-electric.com /cahier_technique/en/abstracts/earthing_systems_LV.htm   (221 words)

 How to apply earthing equipment - Furse
An effective earthing system is a fundamental requirement of any modern structure or system for operational and/or safety reasons.
It is important that earthing conductors should be correctly sized for their application, as they may be required to carry a considerable current for several seconds.
Earth plates are used to attain an effective earth in shallow soils with underlying rocks or in locations with large amounts of buried services.
www.keison.co.uk /furse/apply_earthing_equipment.htm   (590 words)

The function of an earthing and bonding system is to provide an earthing system connection to which transformer neutrals or earthing impedances may be connected in order to pass the maximum fault current.
The earthing system also ensures that no thermal or mechanical damage occurs on the equipment within the substation, thereby resulting in safety to operation and maintenance personnel.
The earthing system also guarantees eqipotential bonding such that there are no dangerous potential gradients developed in the substation.
www.eng.uwi.tt /depts/elec/staff/alvin/ee35t/notes/Substation-Design.html   (2053 words)

 Earthing system - Wikipedia, the free encyclopedia
The choice of earthing system has implications for the safety and electromagnetic compatibility of the power supply.
In a TN earthing system, one of the points in the generator or transformer is connected with earth, usually the star point in a three-phase system.
In single-ended single-phase systems where the Earth and neutral are combined (TN-C and the part of TN-C-S systems which uses a combined neutral and earth core) if there is a contact problem in the PEN conductor, then all parts of the earthing system beyond the break will raise to the potential of the L conductor.
en.wikipedia.org /wiki/Earthing_system   (1784 words)

 Light Education - educazione alle tecniche della luce
In industrial applications the DPR547/55 prescribes that an efficient earthing system must be present in all work places; this does not mean that, in case of verified functional needs, the protection against indirect contacts cannot be obtained with methods that differ from the classic earthing system/automatic breaking combination.
As already mentioned, whenever we are not sure of the presence of an efficient earthing system, it is necessary to protect the equipment with a double insulation of live parts; in this way, even in the case of the giving in of the main insulation, the supplementary insulation remains reliable.
Eventual accessible metal parts (which form part of the external wrapping) must not be connected to the earthing system (if existing) in order to avoid the danger of the extraneous earth, that is the introduction of dangerous electrical potentials caused by failures in other equipments connected to the system.
www.lighteducation.com /print.php?sid=65   (697 words)

 Power Quality - Lightning Protection, Earthing - South Africa
A Surge Suppression earthing system must offer a low impedance at high frequencies and be in close proximity to the TVSS units.
This earthing system must be at the same potential as the mains earth and offer multiple paths into the body of the earth.
Note the lightning protection system must be at the same potential as the mains earthing system.
www.powerquality.co.za /faq.htm   (333 words)

 Grounding vs Bonding Part 6 of 12
You don't have to ground the supplementary electrode to the grounding electrode system of the structure, and you don't have to size the grounding (earthing) conductor for it per 250.66.
If you use a grounding electrode for a lightning protection system, you can't use it as a grounding electrode for the structure grounding electrode (earthing) system required by 250.50.
The concern that bonding the lightning protection system to the building grounding system may create a path for lightning into the electrical wiring or equipment within the structure doesn't justify keeping the two systems separate; separation creates a dangerous potential between them.
www.ecmweb.com /mag/electric_grounding_vs_bonding_6/index.html   (1357 words)

 WRICON   (Site not responding. Last check: 2007-10-13)
Safe and effective electrical earthing is the essential requirement of all electrical installations, and the use of reinforced concrete foundations is an excellent method of achieving this aim.
The WRICON Earthing System permits the installation of an indestructible, totally reliable and constant electrical earth.The heart of the WRICON Earthing System is the unique Earthing Terminal Plate which allows earthing to the building frame (foundations or rebar) to be installed easily, simply and very professionally by any person who can weld proficiently.
Earthing to the building frame (foundations or rebar) is permitted under the E.W.R. of New Zealand and the use of WRICON Earthing System has obvious advantages:-
www.contractconnections.co.nz /wricon.shtml   (300 words)

 The IT Earthing System (unearthed neutral) in LV   (Site not responding. Last check: 2007-10-13)
The IT Earthing System (unearthed neutral) in LV The IT system earthing (unearthed neutral) in LV Although all Earthing Systems offer users the same degree of safety, they do not all have the same operating characteristics.
After a brief introduction of the electrical hazard and the various earthing systems, the first fault situations, followed by the double fault specific to the IT system, are studied, and the advantages and disadvantages of this particular earthing system are developed.
Standardised earthing systems, calculation of fault current and of contact voltage, first fault and double fault, fault tracking and elimination means.
www.schneider-electric.com /cahier_technique/en/abstracts/IT_earthing_system.htm   (288 words)

 Surge Two (Grounding)
For good measure, the metal 'earth plane' is at ground level and connected to ground by a system of rods driven into the soil so that it is at local ground potential.
For a 50-60Hz electrical supply, the purpose of the protective earth conductor is to provide a ‘low impedance’; to supply frequency fault currents, so that voltages developed across a length of cable are insufficient to cause a serious electric shock to any people within the installation.
The SPD is connected to the equipment earth conductor (typically the protective earth conductor) which, in turn, is ultimately connected to ground.
www.keytelemetering.com /Surge_Tutorial2.htm   (1027 words)

 SYSTEM EARTHING   (Site not responding. Last check: 2007-10-13)
The general purpose of earthing is to protect life and property in the event of 50/60 Hz faults (short circuit) and transient phenomena (lightning switching operations).
The regulation that one point of every system shall be earthed is designed primarily to preserve the security of the system by ensuring that the potential on each conductor is restricted to such a value as is consistent with the level of insulation applied.
As per IEEE-32 for neutral earthing resistor made from stainless; steel resistance material, the allowable temperature rise for 10,30 or 60 sec time rating is 760°K, 610°K for extended time rating and 385°K for continuous rating.
www.mdresistor.com /mdus/resistances2US.htm   (355 words)

 TT earthing system - Education - Information - Educational Resources - Encyclopedia - Music   (Site not responding. Last check: 2007-10-13)
A TT earthing system is one where there is no connection at all between the customers earth and the neutral terminal of the transformer in the suppliers network.
In most cases the high earth loop impedence means that a RCCB must be used on the whole install.
Bonding of pipework to the earthing system is important because of the rasie in earth potential during a fault but because of the low currents involved this bonding doesn't need to be very big (6mm^2 in the UK).
education.music.us /T/TT-earthing-system.htm   (388 words)

 Grounding versus Bonding Part 2 of 12
The NEC requires you to ground (earth) system windings to limit the voltage imposed on the system from lightning, unintentional contact with higher-voltage lines, or line surges.
You accomplish this grounding (earthing) by electrically connecting the building or structure disconnecting means [225.31 or 230.70]-with a grounding (earthing) electrode conductor [250.64(A)]-to a grounding (earthing) electrode [250.52, 250.24(A) and 250.32(A)].
Grounding (earthing) of electrical equipment doesn't serve the purpose of "providing a low-impedance fault-current path to clear ground faults." In fact, the Code prohibits the use of the earth as the sole return path-because it's a poor conductor of current at voltage levels below 600V [250.4(A)(5) and 250.45(B)(4)].
www.mikeholt.com /mojonewsarchive/GB-HTML/HTML/Grounding-versus-Bonding-Part-2-of-12~20041014.php   (1508 words)

EARTHING - The process of making a satisfactory electrical connection between the structure, including metal skin, of an object or vehicle, and the mass of the earth, to insure a common potential with the earth.
ENTROPY - In communications, a measure of communications system efficiency; that is, entropy is a measure of the random errors (noise) occurring in the transmission of signals, and from this a measure of the efficiency of transmission systems.
The system uses a knowledge base, which is separate from the part of the program that does the inferencing using the knowledge base.
www.sew-lexicon.com /gloss_e.htm   (7284 words)

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