Grounding: Connected (connecting) to grounding or conductive body that extends the grounding connection. Grounding should not be confused with gluing. Devices can be connected to each other, but they are not considered grounded unless they are reconnected to the ground. The size of the GEC should be consistent with table 250.66. The notes at the end of table 250.66 should be taken into account if there are multiple input managers or if there are no input managers. Taking into account the number of service line managers, the size is determined either by the largest non-grounded service line manager or by the corresponding area for parallel drivers. The size of the GEC also depends on the material of the conductor and its connection to electrodes specific to section 250.66(A) through (C). The permitted materials are copper, aluminum, copper-coated aluminum, and articles permitted under section 250.68(C). Concrete coated grounding electrode [250.52(A)(3)] Complementary vs. complementary. Do not confuse the requirements for additional electrodes (250.54) with those for additional electrodes, such as metal groundwater pipe [250.53(D)(2)]. Some errors often occur in design or during construction due to a lack of understanding or misunderstanding regarding grounding, gluing and section 250 of the NEC. Here are some common mistakes: We also have the requirements for the physical installation of each electrode.
In addition to the need to be in contact with the ground, there are specific requirements such as the digging depth that we must follow. Rod and tube electrodes must be at least 8 feet in contact with the ground and installed vertically, unless bedrock is encountered at a depth of less than 8 feet. In this case, the electrode can be installed at an angle or horizontally if necessary. In the event that a pole must be laid flat, it must be buried to a depth of 30 inches. This is a common digging depth for most “manufactured” electrodes. Plate and ground ring electrodes must also be installed at a minimum depth of 30 inches. Service: The ladders and equipment used to provide electrical power from the utility company to the wiring system of the staffed premises. The sweaters that connect. If your grounding electrode system is within 18 inches of the Earth, use copper to connect the grounding electrodes together [250.64(A)]. Cut it by 250.66. Secure the adhesive jumper securely to the surface on which it is worn and protect it from physical damage [250.64(B)]. Ground fault current path: An electrically conductive path from the point of a ground fault on a wiring system through conductors, equipment or ground normally not energized to the power source.
Examples of ground fault current paths are any combination of equipment grounding conductors, metal tracks, and electrical devices. Effective ground fault current path: A low-impedance electrically conductive path intentionally designed to conduct current under grounding fault conditions from the point of a grounding fault on a wiring system to the power source, and that facilitates the operation of the overcurrent protection device or grounding fault detectors. Earth is not considered an effective earth fault current path. NASCAR racers treat their tires with care that borders on fear. Even the most powerful engines are useless if the tires don`t fit properly on the track. And large grounding conductors are useless if your grounding electrode system doesn`t ground the ground properly. In the first case, start by choosing the right tires. In the second, you start by choosing the right electrodes.
Figure 1: The illustration of grounding systems shows the connection between the utility and the load. Courtesy of CDM Smith To repeat, the GEC is the connection of the grounded conductor of the system or equipment to a grounding electrode or to a point in the grounding electrode system. This leads to fault No. 2, defects in the grounding electrode system that often occur in design and construction. The grounding electrode system consists of grounding electrodes present on each building or structure and connected to each other. Elements that are considered grounding electrodes are listed in section 250.52, which includes a concrete coated electrode, a grounding ring surrounding the building or structure, rod and tube electrodes, plate electrodes and other listed electrodes. The NEC describes the minimum requirements, but not necessarily the design or engineering requirements, that allow for a functional system based on the scope of the project. First, we need to understand some of the terms used within CEN when it comes to grounding and linking so that we can fully understand the intent of what is required.