FAQ
Most frequent questions and answers
BASIC
A deep pit is first dug by an electrode for chemical earthing. After digging the pit, a little bit of water is sprinkled in it. The pit is then filled with 40% to 50% chemical powder and the electrode is properly set in it. The end of the electrode is kept a little out of the hole so the reason for keeping it out is that the earthing wire can be easily attached to it. The remaining pit is then filled with chemical powder, after which the earth wire is connected to the reducing socket of the earth electrode. The reducing socket has new welding that we attach to the earthing wire. Your Chemical Earthing is ready which we can start using in the next 2 to 3 days.
A backfill compound is a product which can consist of various materials that help to retain moisture levels in the soil around earthed electrodes. This backfill compound will help to prevent electrical currents from leaking from your earthing system, keeping your property, its contents and occupants safe.
The benefits of Chemical Earthing are as follows:
- Reduces the resistance of the soil.
- It does not need water like earthing like salt and coal so it is also called maintenance-free earthing.
- Chemical earthing life is longer.
- It gives us stable earth resistance in all seasons.
Functional earthing is a type of earthing, that forms a functional part of an electrical installation and is vital to ensuring its trouble-free operation. Interference current can be discharged, testing adapters earthed, and common reference potentials defined for electrical devices and equipment.
Why do I need Earthing?
Unfortunately, our electrical ecosystem is not perfect. It is constantly attacked by high voltages, fault currents,surges, short circuits & lightning all of which can turn deadly. So, any structure which has electricity running through it needs earthing for the protection of property and life.
In that case, we suggest you have the earthing tested. The traditional earthing methods have been plagued with corrosion and low conductivity problems for decades. The conventional earthing system methods have a very short service life. They become ineffective and are as good as no earthing at all.
Our earthing systems have proven over the last decade that a circular cross section is the best suited design for equal & fast dissipation of current through the electrode and into the earth. We have carried out developmental work on the plate – in – pipe design earlier, but dropped it as it was inefficient and prone to long term problems.
Yes, you can install earth electrode without back fill compound. As you are aware that earth resistance value depends on soil characteristics which varies from place to place with seasonal variation, the earth pit without back fill compounds may exhibit different resistance value at different places in different soil conditions.
Since the earthing system works underground, lot of environmental factors come into play to decide the life of the earthing system. They include
- Soil conditions
- Moisture content
- Climate changes
- Soil resistivity
- Types of soil (normal, sandy, semi rocky, rocky etc.)
- Acidity levels of the soil
- Basic maintenance schedule
Apart from the above, it is very crucial that the installation of the earthing system is done as per specifications, non adherence will not only drastically reduce service life of the system but also hinder earth resistance results.
Anyplace where electricity is used, earthing is important for safety of life and property. This can include
- Homes
- Offices
- Telecommunication towers
- Power transmission towers & HT/LT lines
- Power generation plants
- Mines
- Transformers
- High rise buildings
- Production plants
- Refineries
- Windmills etc.
Vivek Earthing Systems is a trusted name in the industry. They have been in the business of earthing systems for over 10 years and have provided solutions to many industries.Vivek Earthing Systems provides a complete range of earthing systems to suit all your needs. Whether you are looking for an earthing system for your home or office, they have it all.Vivek Earthing Systems are the best solutions for your home. Our systems are designed to make your house a healthy and happy place where you can live a life of peace and tranquility.
Resistance is a measure of the opposition to current flow in an electrical circuit. Resistance is measured in ohms, symbolized by the Greek letter omega (Ω). … Insulators: Materials that present high resistance and restrict the flow of electrons. Examples: Rubber, paper, glass, wood and plastic.
Ohm’s Law is a formula used to calculate the relationship between voltage, current and resistance in an electrical circuit. When spelled out, it means voltage = current x resistance, or volts = amps x ohms, or V = A x Ω.
Resistance is defined as inversely proportional to current, or. I∝1R I ∝ 1 R . Thus, for example, current is cut in half if resistance doubles. Combining the relationships of current to voltage and current to resistance gives. I=VR I = V R.
Resistance is a measure of the opposition to current flow in an electrical circuit.
Resistance is defined as the property of the conductor which opposes the flow of electric current. … Resistivity is defined as the resistance offered by the material per unit length for unit cross-section. The SI unit of resistivity is Ohm.
Current is the rate at which electric charge flows past a point in a circuit. In other words, current is the rate of flow of electric charge. Voltage, also called electromotive force, is the potential difference in charge between two points in an electrical field. … Voltage is the cause and current is its effect.
Voltage generates the flow of electrons (electric current) through a circuit. The specific name for the source of energy that creates the voltage to make current flow is electromotive force. … Electrical energy is the energy released when a charge ‘falls’ through a potential difference (voltage)
The ampere, symbol A, is the SI unit of electric current. It is defined by taking the fixed numerical value of the elementary charge e to be 1.602 176 634 ×10−19 when expressed in the unit C, which is equal to A s, where the second is defined in terms of ∆νCs.
Voltage is a measure of the pressure that allows electrons to flow, while amperage is a measure of the volume of electrons. … In this analogy, voltage is equated with the steepness, or pitch, of the river, while amperage is equated with the volume of water in the river.
The N & L stand for Neutral and Load. With your AC line in you should have three wires. Neutral, Load, and Ground. If your wires are color coded for the US then the black wire is Load or Hot, the white wire is Neutral, and the green wire is Ground.
The definition of an insulator is something that is used to keep heat or sound contained, or something that does not conduct electricity. Soundproofing material is an example of an insulator. … Air, cloth and rubber are good electrical insulators; feathers and wool make good thermal insulators.
Electrical insulators are materials with a high resistivity (resistivity is a property of the material) so they can make objects with a high resistance. This allows insulators to prevent electric current from flowing where it’s not wanted. … Air (like in the atmosphere) is actually an excellent electrical insulator.
A conductor is a material which electricity, heat or sound can flow through. An electrical conductor conducts electricity. The ability to conduct electricity is called electrical conductivity. Most metals, like iron and copper, are electrical conductors.
Conductors:
- Silver, copper, gold, aluminum, iron, steel, brass, bronze, mercury, graphit, dirty water, concrete.
Insulators:
- Glass, rubber, oil, asphalt, fiberglass, porcelain, ceramic, quartz, (dry) cotton, (dry) paper, (dry) wood, plastic, air, diamond, pure water.
Earthing
is the process of instant discharge of electrical energy into the earth through a low resistance wire.
Functions of substation earth electrode system. Substation earth electrode systems provide a means to carry and dissipate electric currents into earth under both normal and short-circuit conditions.
Earth Electrode: When a conductor (or conductive plate) is buried in the earth for an electrical earthing system It is known to be Earth Electrode. Earth electrodes are in different shapes like, conductive plate, conductive rod,metal water pipe or any other conductor with low resistance.
TT earthing system :
The T-T system uses an earthed neutral at the supply transformer and an earth electrode at the user’s installation. The electricity supplier provides no earth conductor therefore an electrode is used. The earth electrode is connected to the main earth terminal of the installation.
IT earthing system :
Earthing systems, or grounding systems, are used to connect specific parts of a power system to the earth or ground. These systems are used to protect personnel and electrical systems from shock or damage by providing a direct path for electric currents to flow to the earth.
TNS earthing system :
TN-S: separate protective earth (PE) and neutral (N) conductors from transformer to consuming device, which are not connected together at any point after the building distribution point. TN-C: combined PE and N conductor all the way from the transformer to the consuming device.
TN-C Earthing System :
The Neutral and the protective earth are combined into a single conductor throughout the system. All the exposed & conductive parts of the installation are connected to the PEN conductor. As per the 8(4) of the Electricity Safety, Quality and Continuity Regulations 2002, “Consumer shall not combine the neutral and protective functions in a single conductor in his customer’s installation”.
Earthing is used to protect you from an electric shock. It does this by providing a path (a protective conductor) for a fault current to flow to earth. It also causes the protective device (either a circuit-breaker or fuse) to switch off the electric current to the circuit that has the fault.
The earth wire will be green and yellow (or sometimes bare in old systems). The live wire is brown in new systems and red in old systems.
The earthing wires are essentially made from best quality copper or GI that can be used in various electrical, electronic and automobile instruments. They are made from top quality galvanized metals that provides high durability and great shock resistance.
Soil resistivity (ρ) is expressed in Ohm metres (Ω. m). This corresponds to the theoretical resistance in Ohms of a cylinder of earth with a cross-section area of 1 m2 and a length of 1 m. By measuring it, you can find out how well the soil conducts electric currents.
An earth electrode and earth electrode resistance are defined in BS 7671 as: Earth electrode – conductive part, which may be embedded in the soil or in a specific conductive medium, e.g. concrete or coke, in electrical contact with the Earth.
Earth rods and their fittings are used to provide the interface to ground in all soil conditions in order to achieve satisfactory earthing systems in overhead and underground electricity distribution and transmission networks – providing high fault current capacity on low, medium and high voltage substations, towers.
Earthing is used to protect you from an electric shock. It does this by providing a path (a protective conductor) for a fault current to flow to earth. It also causes the protective device (either a circuit-breaker or fuse) to switch off the electric current to the circuit that has the fault.
Neutral-to-earth voltage (N-E), sometimes called “stray voltage,” is a condition that results when an electrical current flows through a neutral conductor. Most (2 volt) electric lines contain three wires- one “hot” or powered, one neutral and the ground wire.
Rule what is good earthing voltage? is about earthing and states that all metal supports and metallic fittings should be permanently and efficiently earthed. Each stay-wire should be efficiently earthed or an insulator provided in it at a height not less than 3.0 m from the ground.
The principle of grounding is simple: it diverts an electric current which might escape from a device to a metallic conductor (cable) that ends with a stake (rod) buried in the ground.
A Protective Earth (PE) connects the exposed metallic parts of the consumer’s electrical installation, it ensures that all exposed conductive surfaces are at the same electrical potential as the surface of the Earth, to avoid the risk of electrical shock if a person touches a device in which an insulation fault has .. IE earthing Grounding Principles. Grounding is very Importent, ensuring smooth operation of our control systems and to minimize upon electrical shock hazards, noise, static electricity, etc. Therefore, we always should create two separate paths to ground for our Protection Earth (PE) and our Instrumentation Earth (IE).
Earth rods are available in various lengths and diameters. Typical sizes are 17.2 x 3mtr (fixed) and 17.2 x 2mtr (extendable) using an earth rod coupling and driving head.
current dissipated by one Earthing Pipe = Current Density x Surface area of electrode. Max. current dissipated by one earthing pipe = 889.419x 0.942 = 837.83 A say 838 Amps. Number of earthing pipe required = Fault Current / Max.
Thumb Rule for Calculate Number of Earthing Rod
- ρ = Resistivity of earth in Ohm-Meter.
- L = Length of the electrode in Meter.
- d = Diameter of the electrode in Meter.
- K = 0.75 if 25< L/d < 100.
- K = 1 if 100 < L/d < 600.
- K = 1.2 o/L if 600 < L/d < 300
Drive the rod into the ground . Using your hammer, drill, or driving tool, gradually drive the rod vertically into the ground. You need to drive your rod all the way into the ground. The electrical code states that it must have 8 feet (2.4 m) of contact with the ground, so you need to drive it all the way down.
Low resistance grounding is normally used on medium voltage to high voltage systems to limit the ground return current to a high level, typically 100 A or more [1]. … That means it is set up so that the charging current will be less than the ground return current through the neutral resistor.
For measuring soil resistivity Earth Tester is used. It is also called the “MEGGER”. It has a voltage source, a meter to measure Resistance in ohms, switches to change instrument range, Wires to connect terminal to Earth Electrode and Spikes. It is measured by using Four Terminal Earth Tester Instrument.
Neutral-to-earth voltage (N-E), sometimes called “stray voltage,” is a condition that results when an electrical current flows through a neutral conductor. Most (2 volt) electric lines contain three wires- one “hot” or powered, one neutral and the ground wire. … These leaks produce only small amounts of electricity.
Equipment earthing is a connection done through a metal link between the body of any electrical appliance, or neutral point, as the case may be, to the deeper ground soil. The metal link is normally of MS flat, GI flat, GI wire which should be penetrated to the ground earth grid.
Equipment Earthing : This is the prime type of earthing for homes and other buildings. It deals with the afeguarding of noncurrent carrying apparatus and metallic conductors.
Adding charcoal and water in earthing pit decreases soil resistivity. The layer of charcoal and salt helps to maintain low resistance for earth fault currents. Because of the ionic behaviour of salt and charcoal, they will maintain moisture content around the earth pit.
It is crucial for any home to prevent a small short circuit from turning into an electrical fire. In the event your electrical systems malfunction, the grounding rod will vanish all the released current away from your property and down into the ground. … Earthing is used to protect you from any kind of electric shock.
Earth rods and their fittings are used to provide the interface to ground in all soil conditions in order to achieve satisfactory earthing systems in overhead and underground electricity distribution and transmission networks – providing high fault current capacity on low, medium and high voltage substations, towers …
Characteristics of a Good Grounding System
- Good electrical conductivity.
- Conductors capable of withstanding available electrical fault currents.
- Long life – at least 40 years.
- Low ground resistance and impedance.
Take a light bulb holder, connected with two wires i.e., for positive and negative terminals of the bulb. Now insert one of the wires in phase and the other in neutral. The bulb glows indicating the power supply. Take out the wire from neutral and insert it into the Earth’s hole.
Grounding, also called earthing, is a therapeutic technique that involves doing activities that “ground” or electrically reconnect you to the earth. This practice relies on earthing science and grounding physics to explain how electrical charges from the earth can have positive effects on your body.
Earthing means connecting to the dead component (to the part that does not carry current) under normal conditions to the earth. Grounding means connecting the live part, it means the constituent that carries current under normal condition to the earth.
The phase line is the one that carries current, the neutral line provides the return path to balance the flow of current, and finally earthing is purely used for safety purposes.
Difference Between Earthing and Neutral:
Earth : It provides a grounding point for the flow of electricity.
Neutral : It provides a returning point to the flow of electricity.
It is never safe to use the earth wire as a neutral. Consider the ground wire has broken and anything else connected to it will become life once S1 is switched on. It’s just too dangerous. It will cause potentially fatal confusion to the next person to modify the system.
The neutral is always referenced to ground at one, and ONLY one, point. If you touch the neutral to ground anywhere else, you will create the aforementioned ground loop because the grounding system and the nuetral conductor are now wired in parallel, so they now carry equal magnitudes of current.
Without the earth wire, if a fault occurs and the live wire becomes loose, there is a danger that it will touch the case. The next person who uses the appliance could get electrocuted . … As a result, the casing cannot give an electric shock, even if the wires inside become loose.
The earth’s surface has a negative electric charge, and when it comes in contact with human tissue, there is an equalization. The body can take on extra electrons and build up a static electric charge. This is called the Earthing hypothesis. … This could cause a potentially dangerous electrical shock.
Distance From House to Ground Rod
To ensure there is no interference from the footing, the ground rod should be placed no closer than 2 feet from the exterior wall of the house.
10amp = 1rod 200amp ÷ 10amp = 20rod
20 Grounding rod for 200 amp service
50amp = 1 electrode 200amp ÷ 50amp = 4 electrode
4 electrode for 200 amp service
Pipe Earthing It is the most common type of earthing system. In this type of earthing system, a perforated pipe made of galvanized steel/iron of approved length and diameter is buried vertically. The size of the pipe used depends on the magnitude of current and the amount of moisture content in the soil.
The standard for electrical wiring color code in India is as follows. According to the old standard, Red is used for live (or line) power conductor, Black for neutral and Green for protective earth or ground.
There is not one standard ground resistance threshold that is recognized by all agencies. However, the NFPA and IEEE have recommended a ground resistance value of 5.0 ohms or less. According to the NEC, make sure that system impedance to ground is less than 25 ohms specified in NEC 250.56.
The earth resistance mainly implies the resistance between the electrode and the point of zero potential. Numerically, it is equal to the ratio of the potential of the earth electrode to the current dissipated by it. The resistance between the earthing plate and the ground is measured by the potential fall method.
Resistance of earth is the resistance between infinite earth and earth electrode. This depends upon mainly three factors. The resistance of the electrode itself, The contact resistance between electrode surface and soil, The resistivity of soil between the electrode and infinite earth.
An alternating current (I) is passed through the outer electrode C and the voltage is measured, by means of an inner electrode P, at some intermediary point between them. The Earth Resistance is simply calculated using Ohm’s Law: Rg = V/I.
The earth resistance re is normally very low since the earthing system of a commercial supply is usually bonded to the earthing system of the other power transformers (so called common earth).
Basic Methods to Reduce the Resistance to the Ground
- Increase the Rod Thickness. Let’s assume we bury a standard ground rod with L = 300 cm, and d = 1.270 cm, in soil with ρ = 10,000 Ω·cm. …
- Increase the Rod’s Length. …
- Use of Multiple Rods. …
- Treat the Soil to Decrease its Resistivity.
The most effective methods are to increase the depth of the electrode, place several electrodes, and perform a chemical treatment to the soil near the electrodes. Increasing the diameter of the ground rod does not result in a significant reduction in resistance to ground.
LIGHITNING ARRESTER
A lightning arrester is a device used on electric power transmission and telecommunication systems to protect the insulation and conductors of the system from the damaging effects of lightning. The typical lightning arrester has a high-voltage terminal and a ground terminal.
Though the real big difference is simple: an arrester is charged and “operates” when working, while the rod simply attracts and diverts incoming lightning. … When potentially dangerous lightning strikes, the arrester activates and diverts the lightning to ground, where it will disperse harmlessly.
A lightning arrestor is a device that is installed into your electrical panel. It absorbs the excess energy from the lightning strike, and assists in dispersing it to your grounding system. This absorption and movement of the added voltage to the ground prevents damage to your electrical wiring and devices.
Lightning arresters are generally located on both the high and low side of a substation transformer to protect it from strikes coming in either direction.
Surge arrester protects the installation from inside while lightning arrester protects the equipment from outside. Surge arrester protects the system from lightning, switching, electrical faults and other transients voltage and surges while lightning arrester are mainly used for lightning strikes and associated surges.
The types of lightning arresters are rod, sphere, horn, multi gap, electrolyte, and metal oxide. The types of surge arrestors are distribution, low-voltage, station, DC, neutral protection, fiber tube, signal, network, etc. This arrester can be used as a surge arrester.
There are three common types of lightning: cloud to ground, cloud to cloud and cloud to air. Cloud to ground lightning is the most dangerous. The ground is mainly consisted of positively charged particles while the bottom of violent storm clouds have negative charged particles.
Secondary Class
These arrestors cause high voltage overages to ground, though they do not short all the over voltage from a surge. Secondary class arrestors offer the least amount of protection to electrical systems, and typically do not protect solid state technology, or anything that has a microprocessor.
There is no good reason why lightning rods (and the associated assembly consisting of a connection to earth and a ground rod) are not routinely added to houses. … However, most high buildings and other structures do have some kind of lightning protection system incorporated into them.
Do lightning rods attract lightning? No. … Lightning protection systems and strike termination devices (rods) simply intercept a lightning strike and provide a safe and effective path that takes lightning’s harmful electricity to ground.
Advantages of Lightning Arrester:
Damage caused by lightning can be minimized. Easy to use. Provides protection of equipment outside the substation. Damage to the overhead line can be avoided.
Protect Yourself from Lightning Strikes
- Immediately get off elevated areas such as hills, mountain ridges, or peaks.
- Never lie flat on the ground. …
- Never shelter under an isolated tree.
- Never use a cliff or rocky overhang for shelter.
- Immediately get out of and away from ponds, lakes, and other bodies of water.
When You See Lightning, Count The Time Until You Hear Thunder. If That Is 30 Seconds Or Less, The Thunderstorm Is Close Enough To Be Dangerous – Seek Shelter (if you can’t see the lightning, just hearing the thunder is a good back-up rule). Wait 30 Minutes Or More After The Lightning Flash Before Leaving Shelter.
The 30/30 rule is a recommendation to prevent the risk of a lightning strike during a thunderstorm that tells us when it´s time to look for refuge and when the danger is over.
CABLE TRAY
In the electrical wiring of buildings, a cable tray system is used to support insulated electrical cables used for power distribution, control, and communication.
Cable trays are made of either steel, aluminium or fibber reinforced plastic (FRP) and are available in six basic types,
- Ladder Type Cable Tray.
- Solid Bottom Cable Tray.
- Trough Cable Tray.
- Channel Cable Tray.
- Wire Mesh Cable Tray.
- Single Rail Cable Tray
According to the National Electrical Code (NEC), a cable tray is a unit or assembly of units or sections and associated fittings forming a rigid structural system used to securely fasten or support cables and raceways.
Cable trays simplify the wiring system design process and reduces the number of details. Cable tray wiring systems are well suited for computer aided design drawings. A spread sheet based wiring management program may be used to control the cable fills in the cable tray.
Generally, cable ladders are preferred for supporting high volume or heavy cabling, especially if there are long spans between supports. Cable trays are typically used for light weight cable support, in addition to instrumentation and tubing.
Punching or perforated cable tray is used to lay of the control cables. 50 mm, 75 mm, 100 mm, 150 mm, 300 mm, 450 mm, 600 mm, 700 mm and 900 mm are the sizes of perforated tray. Perforated cable tray sizes: 50 mm, 75 mm, 100 mm, 150 mm, 300 mm, 450 mm, 600 mm, 700 mm and 900 mm. Constant height: 25 mm.
Weight of 25Sq.mm Cable = No of Cable X Weight of Each Cable. Weight of 25Sq.mm Cable =3X0. 5= 1.5 Kg/Meter. Total Weight of All Cables laying in Tray = (11.8+12.2+1.5) Kg/Meter.
Cable trays are for cables. A group of wires surrounded but an overall jacket. Wireways are for wires, Individual insulated conductors such as THHN. Wireways can also used for cables, but normally for low voltage cables.
Perforated cable trays have holes on bottom to provide enough ventilation and position for cable lines. Anti-corrosion, fire, moisture due to the pre-galvanized, hot-dipped powder coated, epoxy coated finish. … Safe and smooth edge protects cable lines from scratch.
Solid Bottom Cable Tray(SBCT) are typically used in applications that generate minimum heat, such as Electrical, Data & Telecommunications, they offer maximum protection for wires. SBCT is also known as Race Ways, Cable Trunking and Cable Ducting.
We are engaged in offering Perforated Type Cable Trays that have uniform holes and are suitable for cables that require both a degree of protection from external damages and ventilation. These are constructed from galvanized iron and mild steel.
Ladder Type Cable Tray are used to distribute cable and has been designed carefully keeping in mind industrial requirements. These trays are manufactured using top quality material and are available in various sizes.
CAST IRON
Cast iron is a group of iron-carbon alloys with a carbon content more than 2%. Its usefulness derives from its relatively low melting temperature.
Cast iron is iron that has been melted, poured into a mould, and allowed to cool. Typically cast iron contains 2-4% carbon, it is non-malleable, hard and brittle. … Wrought iron is iron that has been heated before being worked with tools to shape it.
The bearing surfaces of manhole frames and covers are machined to assure flatness and prevent them from becoming dislodged by traffic.
Plastic Earth Pit Cover are provided over earthing top to do health check as well as checking and recording Earthing Resistance value.In order to avoid masonry work at site ready made earth pit covers were introduced. … Earthing Covers are made of high density poly Polypropylene.
Purpose of Earthing :
To protect buildings, machinery & appliances under fault conditions. To ensure that all exposed conductive parts do not reach a dangerous potential. To provide safe path to dissipate lightning and short circuit currents.