All Stories
Showing posts with label Earthing System. Show all posts
Showing posts with label Earthing System. Show all posts

Saturday, October 19, 2013

Earth Electrode
What is Earth Electrode?
The term electrode means "a way in or a way out for electricity". The bare copper conductor plate or strip or water pipe or gas pipe or any other conductors are used for earth electrodes.The electrode must be an underground, cold water, metal piping system. The earth electrode is the way into the earth for the electrons. In general we use the one or more electrodes in earthing system for efficient earthing purpose. A good earth electrode is that to maintain a good contact with the earth. The one responsibility of earth electrode is that it maintains zero potential between ground and the non-current carrying metal parts of electrical equipment and enclosures. The earth continuity conductor in an electrical installation must be connected at the main intake to an earth electrode which affords a path of low resistance to the earth. Generally in domestic wiring system, we use a mains, water pipe as an earth electrode and a factory or commercial premises (over 12kv) have a its own individual electrode.
The main purpose of an electrode is to provide and maintain good continuity with earth at all times. The following are the types of electrodes such a 'copper plates, copper rods, and strips.

 Pipe Earthing:
In Pakistan generally for earth electrode G.I pipe and copper plates are used. A Galvanized iron pipe of minimum 40mm diameter and minimum length of 2.7m is buried in the earth. It may be more in case of dry and rocky soil. The pipe is provided with the tapped casing at the lower end so that it can be driven into the soil easily. Alternate layers of salt and charcoal are placed around the pipe up-to 2 meter from the bottom end and 15cm around the pipe. The layer of salt and charcoal increases the resistance. An arrangement is made to pour water into the pipe periodically so that soil remains moist. Another pipe of 1.9em diameter is connected at the top of that pipe through a reducing socket. water pipes offer good conductance to earth. The actual resistance usually a fraction of an ohm. The low resistance of such systems is due to their size and the fact that the pipes, are in contact with a great volume of earth.

Rod Earthing:
Artificial grounding electrodes should also be used. Such electrodes may be rods, pipes, plates or conductor embedded in the earth. They should be of no-corrosive metal, such as copper or copper bearing steel. Copper electrodes are widely used as electrode. It is made in a range of diameters from (1/2in) to (1in). These copper rods are available to many parts length. The minimum length of copper rod at 8 feet with a minimum diameter of 1/2 inch. The driven grounds consist of rods driven into the ground deeply enough so that they are in contact with perpetually moist soil. A G.I-steel rod or copper rod is driver into the ground. The rod should be driven until the top end is 4 to 6 inch below the ground level. If driving is difficult, a bar may be used to make the hole before the rod is driven.
A person can accommodate a rod at any length, as the driving hammer slides over the rod. If many ground rods have to be driven, a power hammer can be used. After the rod is driven in place, connection is made with the ground wire. A bronze clamp is used for connection. The clamp is placed over the ground rod and end the round wire end.
The sectional grounding rods are also used. The section are threaded at each end. The usual section length is 8, 10 or 12ft. The installation procedure of sectional ground rods is as follows. The coupling and driving stud are screwed on the top end of the sectional rod. The assembly is then driven until the coupling on the rod reaches the ground level, and then driving stud is removed coupling. Another coupling is screwed onto the top end of the second sectional rod and then driving stud is screwed into the second coupling. And finally, the driving is now continued until the second section reaches ground level.

Plate Earthing:
The plate is also used for electrode. The electrode plate is installed below water level. The plate should be installed in vertical position and completely surrounded by a bed of at least 1ft of charcoal mixed with lime, salt, charcoal, chalk power etc. This mixture increases the size of plate and also maintains moisture surrounded by the plate. The electrode plate is buried at least 1ft below of the water level. If we use double earthing, then the distance both two plates in 20 to 30ft.
In Pakistan two types of earthing plates are commonly used. A copper  plate, which is 2 feet in length and fraction width, the thickness of copper plate, is 1/8 inch (600*600*3). The other plate which is used for electrode is iron made. The thickness of this plate is 6mm. The Plate is connected to a G.I pipe of 12.7mm diameter for pouring water around the plate. The earth wire is either bolted or welded to plate and is taken out along with G.I pipe.

Strip Earthing:
A copper strip (25mm*1.6mm) and (25mm*4mm)in case of G.I are buried horizontally in trenches of sufficient depth (8m or higher). This type of earthing is most suitable for places having rocky soil.

What is Earth Electrode?

Earth Electrode
What is Earth Electrode?
The term electrode means "a way in or a way out for electricity". The bare copper conductor plate or strip or water pipe or gas pipe or any other conductors are used for earth electrodes.The electrode must be an underground, cold water, metal piping system. The earth electrode is the way into the earth for the electrons. In general we use the one or more electrodes in earthing system for efficient earthing purpose. A good earth electrode is that to maintain a good contact with the earth. The one responsibility of earth electrode is that it maintains zero potential between ground and the non-current carrying metal parts of electrical equipment and enclosures. The earth continuity conductor in an electrical installation must be connected at the main intake to an earth electrode which affords a path of low resistance to the earth. Generally in domestic wiring system, we use a mains, water pipe as an earth electrode and a factory or commercial premises (over 12kv) have a its own individual electrode.
The main purpose of an electrode is to provide and maintain good continuity with earth at all times. The following are the types of electrodes such a 'copper plates, copper rods, and strips.

 Pipe Earthing:
In Pakistan generally for earth electrode G.I pipe and copper plates are used. A Galvanized iron pipe of minimum 40mm diameter and minimum length of 2.7m is buried in the earth. It may be more in case of dry and rocky soil. The pipe is provided with the tapped casing at the lower end so that it can be driven into the soil easily. Alternate layers of salt and charcoal are placed around the pipe up-to 2 meter from the bottom end and 15cm around the pipe. The layer of salt and charcoal increases the resistance. An arrangement is made to pour water into the pipe periodically so that soil remains moist. Another pipe of 1.9em diameter is connected at the top of that pipe through a reducing socket. water pipes offer good conductance to earth. The actual resistance usually a fraction of an ohm. The low resistance of such systems is due to their size and the fact that the pipes, are in contact with a great volume of earth.

Rod Earthing:
Artificial grounding electrodes should also be used. Such electrodes may be rods, pipes, plates or conductor embedded in the earth. They should be of no-corrosive metal, such as copper or copper bearing steel. Copper electrodes are widely used as electrode. It is made in a range of diameters from (1/2in) to (1in). These copper rods are available to many parts length. The minimum length of copper rod at 8 feet with a minimum diameter of 1/2 inch. The driven grounds consist of rods driven into the ground deeply enough so that they are in contact with perpetually moist soil. A G.I-steel rod or copper rod is driver into the ground. The rod should be driven until the top end is 4 to 6 inch below the ground level. If driving is difficult, a bar may be used to make the hole before the rod is driven.
A person can accommodate a rod at any length, as the driving hammer slides over the rod. If many ground rods have to be driven, a power hammer can be used. After the rod is driven in place, connection is made with the ground wire. A bronze clamp is used for connection. The clamp is placed over the ground rod and end the round wire end.
The sectional grounding rods are also used. The section are threaded at each end. The usual section length is 8, 10 or 12ft. The installation procedure of sectional ground rods is as follows. The coupling and driving stud are screwed on the top end of the sectional rod. The assembly is then driven until the coupling on the rod reaches the ground level, and then driving stud is removed coupling. Another coupling is screwed onto the top end of the second sectional rod and then driving stud is screwed into the second coupling. And finally, the driving is now continued until the second section reaches ground level.

Plate Earthing:
The plate is also used for electrode. The electrode plate is installed below water level. The plate should be installed in vertical position and completely surrounded by a bed of at least 1ft of charcoal mixed with lime, salt, charcoal, chalk power etc. This mixture increases the size of plate and also maintains moisture surrounded by the plate. The electrode plate is buried at least 1ft below of the water level. If we use double earthing, then the distance both two plates in 20 to 30ft.
In Pakistan two types of earthing plates are commonly used. A copper  plate, which is 2 feet in length and fraction width, the thickness of copper plate, is 1/8 inch (600*600*3). The other plate which is used for electrode is iron made. The thickness of this plate is 6mm. The Plate is connected to a G.I pipe of 12.7mm diameter for pouring water around the plate. The earth wire is either bolted or welded to plate and is taken out along with G.I pipe.

Strip Earthing:
A copper strip (25mm*1.6mm) and (25mm*4mm)in case of G.I are buried horizontally in trenches of sufficient depth (8m or higher). This type of earthing is most suitable for places having rocky soil.

6 comments
Posted at 8:15 AM |  by Unknown

Saturday, October 5, 2013

earthing lead

The earthing lead is the final conductor to earth electrode. The color  of earthing lead insulation is green. This is the final conductor which makes the connection between the earth connecting point and earth electrode. The copper wire and strip can be used as earthing lead. When we use the copper wire enclosed in (G.I) pipe and then made connection to earth electrode. It is recommended that the earthing lead is jointed with earth electrode at least two places. The joint between earthing lead and earth electrode should be covered with bitumen before burying the plates in ground. The joints must be tight and clean for sound earthing. The (earth electrode) is mechanically sound and protected against mechanical damage and collision. The earthing lead must have a minimum size of 66 m2, with a maximum of 20 mm2 according to circuit conductor size. The earthing lead actually completes two grounding paths to the grounding electrode.
(1) The path from the earth continuity conductor.
(2) The path from the equipment grounding conductor when a wire is used as the equipment grounding conductor.
The material for earth lead is copper, aluminum etc are commonly used. When we install a earthing lead without an enclosure, it must be securely fastened to the construction surface on which it is carried.

What is Earthing Lead?

earthing lead

The earthing lead is the final conductor to earth electrode. The color  of earthing lead insulation is green. This is the final conductor which makes the connection between the earth connecting point and earth electrode. The copper wire and strip can be used as earthing lead. When we use the copper wire enclosed in (G.I) pipe and then made connection to earth electrode. It is recommended that the earthing lead is jointed with earth electrode at least two places. The joint between earthing lead and earth electrode should be covered with bitumen before burying the plates in ground. The joints must be tight and clean for sound earthing. The (earth electrode) is mechanically sound and protected against mechanical damage and collision. The earthing lead must have a minimum size of 66 m2, with a maximum of 20 mm2 according to circuit conductor size. The earthing lead actually completes two grounding paths to the grounding electrode.
(1) The path from the earth continuity conductor.
(2) The path from the equipment grounding conductor when a wire is used as the equipment grounding conductor.
The material for earth lead is copper, aluminum etc are commonly used. When we install a earthing lead without an enclosure, it must be securely fastened to the construction surface on which it is carried.

2 comments
Posted at 4:40 AM |  by Unknown

Friday, October 4, 2013

3 core cable

In every electrical installation, unless it has no metal in it other than the current carrying conductors, has an earth-continuity conductor in it which is electrically continuous through out the installation. This is a cable or any other conductor, which is connected together all metal parts of an electrical installation. e.g switch fuses, fuse distribution board, steel conduit, metal frame work on which electrical apparatus is mounted. The earth continuity conductor is connected to earthing lead at a connecting point.
In a metal conduit system the conduit itself may act as a earth continuity conductor. It may be meta sheathing of cables or special continuity wire enclosed in the cable sheath. In  the case of portable appliances the third end larger pin of the plug socket outlets is used for this purpose. When the metal sheathing of cables or metal conduit is used as an earth-continuity conductor then all joints should be tight and bonded together and be protected where necessary against corrosion.
According to I.E.E.E regulation, the following shall be connected to the earth-continuity conductor, the earthing terminal provided at every lighting point and exposed metal parts of the apparatus.
The (e.c.c) shall be connected to jointed point. This bonding or jointing point must be in and this accessible point accessible point can be anywhere?
I.E.E regulation (E3) require that where earth-leakage protection relies on the operation of fuses or excess current circuit earthing terminal and the remote end of every (e.c.c) shall not exceed one ohm (1 ohm). When (e.c.c) is bonded to casing of apparatus, it should be tightly clamped by the special screw provided on the casing. In  Pakistan the electrical apparatus (e.f motors transformers, generators, machinery using, electrical power apparatus used for regulating or controlling electrical energy and all medium voltage apparatus) must be earthed by the two  separate to connections with earth. The both two earth leads are not joined to one earth electrode, while separately jointed two earth electrodes. The distance between two earth electrodes is 5 ohms to 8 ohms. Remember that, where the (e.c.c) is connected in a flexible cable or cord it should have a cross-sectional area equal to the largest current-carrying conductor of that cable or cord. Every (e.c.c) which is not contained in a composite or flexible cable must me insulated by the color green or yellow. Where the sheath of a composite cable is removed adjacent to joints, the (e.c.c) must be insulated. The resistance of the consumer's (e.c.c) should not exceed (1 ohm).

Earth-Continuity Conductor

3 core cable

In every electrical installation, unless it has no metal in it other than the current carrying conductors, has an earth-continuity conductor in it which is electrically continuous through out the installation. This is a cable or any other conductor, which is connected together all metal parts of an electrical installation. e.g switch fuses, fuse distribution board, steel conduit, metal frame work on which electrical apparatus is mounted. The earth continuity conductor is connected to earthing lead at a connecting point.
In a metal conduit system the conduit itself may act as a earth continuity conductor. It may be meta sheathing of cables or special continuity wire enclosed in the cable sheath. In  the case of portable appliances the third end larger pin of the plug socket outlets is used for this purpose. When the metal sheathing of cables or metal conduit is used as an earth-continuity conductor then all joints should be tight and bonded together and be protected where necessary against corrosion.
According to I.E.E.E regulation, the following shall be connected to the earth-continuity conductor, the earthing terminal provided at every lighting point and exposed metal parts of the apparatus.
The (e.c.c) shall be connected to jointed point. This bonding or jointing point must be in and this accessible point accessible point can be anywhere?
I.E.E regulation (E3) require that where earth-leakage protection relies on the operation of fuses or excess current circuit earthing terminal and the remote end of every (e.c.c) shall not exceed one ohm (1 ohm). When (e.c.c) is bonded to casing of apparatus, it should be tightly clamped by the special screw provided on the casing. In  Pakistan the electrical apparatus (e.f motors transformers, generators, machinery using, electrical power apparatus used for regulating or controlling electrical energy and all medium voltage apparatus) must be earthed by the two  separate to connections with earth. The both two earth leads are not joined to one earth electrode, while separately jointed two earth electrodes. The distance between two earth electrodes is 5 ohms to 8 ohms. Remember that, where the (e.c.c) is connected in a flexible cable or cord it should have a cross-sectional area equal to the largest current-carrying conductor of that cable or cord. Every (e.c.c) which is not contained in a composite or flexible cable must me insulated by the color green or yellow. Where the sheath of a composite cable is removed adjacent to joints, the (e.c.c) must be insulated. The resistance of the consumer's (e.c.c) should not exceed (1 ohm).

3 comments
Posted at 7:34 AM |  by Unknown
A ground is a conducting connection. whether intentional or accidental between an electrical circuit or equipment and earth or to come conducing body which serves in place of the earth.
Earthing system

 An earthing is defined as a connection to the general mass of earth. The term 'ground' is used in electrical work to refer to the earth as the zero of potential. Actually, a ground consists of artificial connection to the earth. having a very low resistance. The resistance of ground is low, therefore maximum current flow through it. The principle of earthing is always followed in electrical installation for the following reasons. Every electric supply electric distribution system has one of its conductors connected to earth at some control point. Water mains and cable sheath's are the best grounds obtainable. The best connection main is obtained by welding or soldering the connecting wire so as to eliminate any possibility of the connection loosening or burning off.
The  earth rarely serves as a part of the return circuit. The I.E.E regulations require that every item of electrical apparatus and every conductor apparatus and every conductor operating at a voltage exceeding extra-low voltage must be effectively prevented by use of earthing. Earthing conductor's need to satisfy two main requirements, namely to be strong enough to withstand any mechanical damage and also to be of sufficiently low impendence to meet the need to carry an earth fault current without danger.
An efficient earthing arrangement is an essential part of every electrical system to guard against the effects of leakage currents. short circuit, etc. The protective devices in the circuit (e.g fuses or C.B's) must operate so as to disconnect the fault within the maximum times specified in the regulations. The term earthed is used in electrical work to refer is connected to earth or to some conducting body which serves in place of the earth. The practice of earthing any metal which may come into contact with a live conductor  means that the leaking current is offered a path of much lower resistance than the human body. which carries is away safely.
The term 'earth' includes any type of floor which is hygroscopic e.g concrete, quarry, marble or other stone tiles. I.E.E regulation DI states that every item of apparatus and every conductor shall be prevented from giving rise to earth leakage currents by all-insulated construction by double insulation, by isolation or by earthing of exposed metal parts.Grounding in interior wiring systems is done for safety purpose and two classes of ground are connected in a system is connected to ground.

Equipment grounding is the connection between non-current carrying motor frames metallic parts in electrical installation to earth. (e.g metallic conduit, switch boxes etc.) Solid grounding or effective grounding means that the neutral is directly connected to ground without any resistance, inductor or capacitor in between neutral and ground.

What is Earthing system?

A ground is a conducting connection. whether intentional or accidental between an electrical circuit or equipment and earth or to come conducing body which serves in place of the earth.
Earthing system

 An earthing is defined as a connection to the general mass of earth. The term 'ground' is used in electrical work to refer to the earth as the zero of potential. Actually, a ground consists of artificial connection to the earth. having a very low resistance. The resistance of ground is low, therefore maximum current flow through it. The principle of earthing is always followed in electrical installation for the following reasons. Every electric supply electric distribution system has one of its conductors connected to earth at some control point. Water mains and cable sheath's are the best grounds obtainable. The best connection main is obtained by welding or soldering the connecting wire so as to eliminate any possibility of the connection loosening or burning off.
The  earth rarely serves as a part of the return circuit. The I.E.E regulations require that every item of electrical apparatus and every conductor apparatus and every conductor operating at a voltage exceeding extra-low voltage must be effectively prevented by use of earthing. Earthing conductor's need to satisfy two main requirements, namely to be strong enough to withstand any mechanical damage and also to be of sufficiently low impendence to meet the need to carry an earth fault current without danger.
An efficient earthing arrangement is an essential part of every electrical system to guard against the effects of leakage currents. short circuit, etc. The protective devices in the circuit (e.g fuses or C.B's) must operate so as to disconnect the fault within the maximum times specified in the regulations. The term earthed is used in electrical work to refer is connected to earth or to some conducting body which serves in place of the earth. The practice of earthing any metal which may come into contact with a live conductor  means that the leaking current is offered a path of much lower resistance than the human body. which carries is away safely.
The term 'earth' includes any type of floor which is hygroscopic e.g concrete, quarry, marble or other stone tiles. I.E.E regulation DI states that every item of apparatus and every conductor shall be prevented from giving rise to earth leakage currents by all-insulated construction by double insulation, by isolation or by earthing of exposed metal parts.Grounding in interior wiring systems is done for safety purpose and two classes of ground are connected in a system is connected to ground.

Equipment grounding is the connection between non-current carrying motor frames metallic parts in electrical installation to earth. (e.g metallic conduit, switch boxes etc.) Solid grounding or effective grounding means that the neutral is directly connected to ground without any resistance, inductor or capacitor in between neutral and ground.

3 comments
Posted at 7:32 AM |  by Unknown
Subscribe to: Posts (Atom)
back to top