On low voltage electricity networks with a phase to neutral voltage exceeding 240 V to 690 V, which are mostly used in industry, mining equipment and machines rather than publicly accessible networks, the earthing system design is equally important from safety point of view as for domestic users. Also, TT networks do not pose any serious risks in the case of a broken neutral. In some countries (such as the UK) TT is recommended for situations where a low impedance equipotential zone is impractical to maintain by bonding, where there is significant outdoor wiring, such as supplies to mobile homes and some agricultural settings, or where a high fault current could pose other dangers, such as at fuel depots or marinas. There is no 'earth wire' between the two. For similar reasons, most countries have now mandated dedicated protective earth connections in consumer wiring that are now almost universal. In a TT (Latin: terra-terra) earthing system, the protective earth connection for the consumer is provided by a local earth electrode, (sometimes referred to as the Terra-Firma connection) and there is another independently installed at the generator. Laboratory rooms, medical facilities, construction sites, repair workshops, mobile electrical installations, and other environments that are supplied via engine-generators where there is an increased risk of insulation faults, often use an IT earthing arrangement supplied from isolation transformers.
The main attraction of a TN network is the low impedance earth path allows easy automatic disconnection (ADS) on a high current circuit in the case of a line-to-PE short circuit as the same breaker or fuse will operate for either L-N or L-PE faults, and an RCD is not needed to detect earth faults. If the fault path between accidentally energized objects and the supply connection has low impedance, the fault current will be so large that the circuit overcurrent protection device (fuse or circuit breaker) will busbar machine open to clear the ground fault. When current flows from a line conductor to an earth wire, as is the case when a line conductor makes contact with an earthed surface in a Class I appliance, an automatic disconnection of supply (ADS) device such as a circuit breaker or a RCD will automatically open the circuit to clear the fault. In most developed countries, 220 V, 230 V, or 240 V sockets with earthed contacts were introduced either just before or soon after World War II, though with considerable national variation.
Where the earthing system does not provide a low-impedance metallic conductor between equipment enclosures and supply return (such as in a TT separately earthed system), fault currents are smaller, and will not necessarily operate the overcurrent protection device. Busbars are typically made of copper or aluminum and used to conduct electricity within electrical equipment. Radio antennas may require particular grounding for operation, as well as to control static electricity and provide lightning protection. In the event of a surge, a lightning arrester, a surge arrester or a SPD will divert the excess current to the Earth before it reaches an appliance. Tall structures may have lightning rods as part of a system to protect them from lightning strikes. Telegraph lines may use the Earth as one conductor of a circuit, saving the cost of installation of a return wire over a long circuit. In the distribution networks, where connections are fewer and less vulnerable, many countries allow the earth and neutral to share a conductor. In low-voltage networks, which distribute the electric power to the widest class of end users, the main concern for design of earthing systems is safety of consumers who use the electric appliances and their protection against electric shocks.
They manufacture equipment for various industries, including power generation, oil and gas, and chemical production. This was permitted for plug-in equipment and permanently connected equipment. While the national wiring regulations for buildings of many countries follow the IEC 60364 terminology, in North America (United States and Canada), the term "equipment grounding conductor" refers to equipment grounds and ground wires on branch circuits, and "grounding electrode conductor" is used for conductors bonding an Earth/Ground rod, electrode or similar to a service panel. Regulations for earthing systems vary among countries, though most follow the recommendations of the International Electrotechnical Commission (IEC). Regulations may identify special cases for earthing in mines, in patient care areas, or in hazardous areas of industrial plants. In addition to electric power systems, other systems may require grounding for safety or function. The company has a rich history dating back to 1898 and has become one of the leading names in the power industry. They are one of the largest busbar machine manufacturers in the world, and they offer a wide range of products used in various industries.
