How electricians test continuity of protective conductors eep. All tests shall be carried out in the presence of the. This corresponds to the theoretical resistance in ohms of a cylinder of earth with a crosssection area of 1 m2. Soares book on grounding and bonding, 9th edition, for added information. Grounding electrode conductors are sized using section 250. All protective and bonding conductors must be tested to ensure that they are. The protective conductor may have a different crosssectional area to that of the phase and neutral. Earthing clamp earthing grid conductors are connected to the earth rods, already driven into the ground, by means of earthing clamps.
Code of practice for the electricity wiring regulations 2015 edition. Electrical testing with the use of electrical test meters, including. A combination of furse earth electrodes, soil conditioning, conductors and equipotential bonding bars provide an effective, low resistance dissipation from the lightning protection system to earth. The system earthing is the intentional connection of a circuit conductor typically the neutral on a three phase, four wire system protective earth pe to earth.
Also contains an example of calculating the minimum size of protective conductor. The testing of electrical installations hellermanntyton. The iee wiring regulations explained and illustrated. Qr code 1 main protective bonding test companion websites. Once a protection system is decided upon, it is verified whether the building in question is fully covered by the protection system, using the zone of protection principle. Safearth technical article earthing tests making the right choice. Size and price versus functionality is what the compromise has become. For all protective conductors, including main and supplementary bonding conductors, electricians must perform continuity test using a. Abb manuals ac circuit ac machines advance circuit. Earthing grounding quiz questions electrician exams. It does this by providing a path a protective conductor for a fault current to flow to earth. Earthing ranks right up there with the discovery of penicillin. General requirements for electrical earthing or grounding. Code of practice for the electricity wiring regulations.
Earth conductors are also referred to as earth or earth lines and are designated by the letters pe, which stand for protective earth. This book is probably the most important health read of the 21st centur ann louise gittleman, ph. The book emphasizes earthing, bonding, protection, and circuit design of electrical wirings. Mesh type of protection with a combination of vertical and horizontal air terminals, down conductors and earth electrodes is the most common type of protection adopted. Electrical installations level 3 pearson schools and fe colleges. View now we wrote the book on grounding and earthing. The iee wiring regulations explained and illustrated, second edition discusses the recommendations of the iee regulations for the electrical equipment of buildings for the safe selection or erection of wiring installations. That part of the earthing system which interconnects the overall metallic parts of electrical installation e. Earthing of generators and uninterruptible power supplies upss supplying low voltage installations bs 7430 defines the elements for creating an appropriate earthing arrangement for a low voltage installation, including a main earthing terminal, protective conductors, earthing conductors and circuit protective conductors, and the use of. For main equipotential bonding, there is no single fixed value of resistance above which the conductor would be deemed unsuitable.
Electrical installation handbook protection, control and. A 230v circuit containing a surge protection device is to be tested for insulation resistance and the device cannot be removed. Description of earthing, and a look at some of the regulations applicable to it. It typically involves checks of the presence, appropriate redundancy, suitability and visible condition of earthing conductors, connections, surface layer materials and connected equipment and is typically recommended at intervals of between 1 and 3 years. Protective earthing pe conductor sizing software cable. For all protective conductors, including main and supplementary bonding conductors, electricians must perform continuity test using a lowreading ohmmeter. The neutral and protective earth conductor enters the installation as a single combined conductor, up to a point mostly the meter box on the side of the house or the porch where the earth and neutral are connected together and then run into the rest of the installation as separate conductors. The results of these evaluations are a valuable data base during the test of the.
Earth electrode is to consist of one or more earth rods also earth plate or earth matt, interconnected by buried earthing tape or cable, which is to have a total combined resistance value, during any season of the year and before interconnection to other earthed systems or earthing means, not exceeding i ohm. Do not use high voltage testing equipment as it will destroy the. Protection against lightning a uk guide to the practical. Main protective conductor functional earthing conductors main earth terminal measurement bar earth conductor earth electrode metal pipes main equipotential bond soil resistivity soil resistivity. In this case multiply the resistance of the phase or neutral conductor by a factor of 1. Earth rods and conductor systems mechanical earth clamps and bonds soil conditioning agents earth bars and equipotential bonding. It is generally not insulated, and has a minimum crosssection of 25 mm 2 copper or 50 mm 2 galvanised steel. Since earthing has an influence on the levels of power system overvoltages and fault current, and the definition of protection systems, earthing system must be designed to ensure that there is proper operation of the protective devices such as protective relaying and surge arresters. They also have the greenandyellow colour combination, whereby both colours are reserved for this conductor type, and offer protective earthing for people and animals as well as electrical installations earth conductors in electrical installations are fitted. Types of earthing systems used in electrical installations. A practical guide to earth resistance testing weschler instruments.
This is a discussion of the basic principles behind grounding systems and how grounding is related to safety and the effective operation of circuit protection devices such as fuses and circuit breakers. The device is opened in order to measure the earth connection. For premanufactured assemblies, the test must be carried out at 10 a a. Using a long test lead, test between the earth bar in the consumer unit and the cpc at each accessory point. Read all about the earth s natural healing potential to alleviate their aches and pains, inflammation, sleep disorders and free radical damage in this ground breaking book. What you need is bs en602041, electrical equipment of machines part 1. This implies that five conductors need to be routed for a threephase consumer. Types of tests electrical equipment testing metrotest. Earth resistivity test shall be carried out in accordance with british standard code of practice of earthing.
The protectiveearthresistance test measures the impedance between the. Fusing occurs due to the heating effect of the test current the current flows, generating heat and the wire melts apart resulting in an open circuit. Many pat testers nowadays do not have the ability to test an earth by applying 10 amps or 25 amps through the protective earth conductor it is our belief that this is a step backwards as far at pat testers, and safety, are concerned. Protective earthing conductor sizing calculation is based on a selected standard such as nfpa 70 nec section 250. Lightning, surge protection and earthing of electrical. S denotes that the neutral conductor routed from the source is separate from the protective earthing conductor, which is also routed from the source. Now i have looked at gn3 and also bs7671 page 158 notes under table 61. It also causes the protective device either a circuitbreaker or fuse to switch off the electric current to the circuit that has. Design of earthing grounding system in a substation grid.
Earth leakage and earth fault currents 75 11a general 76 11b basic requirements 76 11c protective conductors 77 11d earthing of exposed conductive parts 78 11e equipotential bonding 79 11f supplementary bonding 80 11g main earthing terminal 81 11h earthing conductor 82. How electricians test continuity of protective conductors iaei. In the event of a damaged protective earthing conductor, where most strands are broken, a high current test may also detect the damage by fusing the cable. Global earthing systems one simple definition of a common grounding system. System grounding or earthing involves the ground connection of power services and separately derived systems. Code of practice for protective earthing of electrical installations isoiec 623053 protection. The basic understanding of an earthing protection system. In numerous test on soil with uniform soil resistivity it has been.
They include generator, transformers, uninterruptible power systems ups. C denotes that the neutral conductor and the protective earthing conductor are one and the same conductor. Tncs dc system earthed midpoint conductor m and protective conductor combined in one single conductor pe in a part of the installation. The entire electrical installation shall be subject to the final acceptance of the supervising engineer as well as the local authorities. This is not intended to be a theoretical document, nor a technical catalogue, but, in. In carrying out such inspection and test procedures, precautions must be taken.
Design of protection for electrical and electronic systems within a structure 91 10. Connection is essentially made by tightly clamping of the grid conductor to the rod using the bolt and nut assembly. Note below table 61 bs 7671 cminimum acceptable resistance. Proper earthing is a basic protection against ac line disturbances. Conductor providing the link with the earth electrode. Earthing is used to protect you from an electric shock.
How electricians test continuity of protective conductors. Earthground measurement guide chauvin arnoux metrix. In the uk, this system is also known as protective multiple earthing pme, because of the practice of connecting the combined neutralandearth conductor via the shortest practicable route to a local earthrod at the source and at each premises, to provide both system earthing and equipment earthing at each of these locations. For all protective conductors, including main and supplementary bonding conductors, electricians must perform a continuity test using a lowreading ohmmeter. Protection measures touch and step voltages 86 section 9. Principles of electrical grounding john pfeiffer, p.