(b) Stainless steel rod and copper or galvanized steel grounding electrodes shall be at least 5 to 8 inches (15.87 mm) in diameter unless otherwise specified. (NEC 2017) In your home`s wiring system, the grounding system is an essential safety feature. In the event of a system failure, the grounding system provides a path with the least resistance, ensuring that the current returns safely to the ground itself. Thus, it reduces the likelihood that a short circuit can cause a fire or a potentially fatal shock. The last and most important part of a home`s grounding system consists of a metal grounding rod driven deep into the ground, wiring that connects this rod to a service disc or grounding tab on the power meter, and the connection terminal between the wiring and the rod. Section 250 contains general requirements for grounding and gluing electrical installations. Sections 250.52(A)(1) to (A)(7) instruct users that all grounding electrodes on each building or structure must be interconnected to form the grounding electrode system. If none of these grounding electrodes are present, one or more of the grounding electrodes specified in paragraphs 250.52(A)(4) to (A)(8) shall be installed and used (see Figure 3). Floor bars are available in lengths of 8 feet and 10 feet, with 8 feet being the most commonly used size in gated communities. As a general rule, floor bars should be at least eight feet long and should not be cut. In very dry soil, which offers more resistance than wet soil (meaning it doesn`t accept electricity as easily), soil stems are sometimes stacked and connected by special pliers to allow them to reach deeper into the soil. Wow, did you see it? One of the sites indicates the use and installation of a 5-foot floor bar. But have you also seen the peculiarities of this language? First of all, this is only allowed if the building or structure does not have inter-system connection termination or grounding devices.
In this case, the use of a 5-foot floor bar is allowed. Section 250 of the NEC does not specify a minimum or maximum distance between the main panel and the grounding rod. However, since the plate must be connected to the grounding rod by a buried copper wire, best practices suggest that the shorter the distance from the grounding rod, the more efficient the soil. The standard size of copper wire should not be smaller than that of No. 6 wire, and most codes recommend No. 4 wire. If the grounding rod is located away from the main board, a thicker No. 3 wire may be required. In areas where codes require two grounding rods due to high electrical resistance in the soil, the rods must be spaced at least 6 feet apart and connected by a buried starter wire. Grounding rods are an important part of a safe electrical system.
They create a route for the stray current that occurs during a brief or other malfunction to have an effective route out of a building. To start the installation, you need to find a suitable place to install them, and then push them into the ground. Once the poles are in the ground, you need to make sure they are properly connected to the electrical system they ground. With a little planning and care, you can install grounding rods for a new electrical panel or for an existing electrical panel to minimize the risk of fires and electrical injuries. [1] X Research source The NEC consists of different parts; Next, we must look at Part IV, “Grounding Methods.” Section 800.100 deals with the bonding and grounding of cables and primary protectors. It states that the primary protection and metal bond(s) of the cable sheath shall be glued or grounded in accordance with standards 800.100 (A) to 800.100 (D). This “grounding” is a very important part of your electrical system to ensure electrical safety. According to the National Electrical Code (NEC), a grounding system must have a ground resistance of 25 ohms or less.
To do this, more than one grounding rod may be required. Rod and tube electrodes must be driven into the ground to establish the best contact. If a grounding rod or tube electrode is installed, it must be in direct contact with earth for a distance of at least 8 feet. Sometimes it is difficult to drive an 8- or 10-foot grounding rod or tubular electrode. The solution is not to cut off the exposed part of the stem. This results in NEC values lower than the minimum NEC values required for the electrode to contact with the earth. Section 250 of the NEC does not specify a distance between a house and a grounding rod. But the 8-foot pole should be driven deep enough from the house into the ground so as not to touch the concrete underground base of the house, which protrudes horizontally about 1 foot from the base of the foundation. To ensure that there is no interference from the base, the earthen rod should not be placed less than 2 feet from the exterior wall of the house. Whenever possible, floor rods should penetrate into the moist soil around your home.
Normally, the area near the foundation contains enough moisture from downspout runoff. For 200 amp services, a #4 grounding electrode conductor (grounding wire) is required. It is unwise and dangerous to install the shorter 4-foot grounding rods often sold for grounding TV antennas and other individual devices. These are not legal for home electrical service grounding and can cause your grounding system to fail when it is most needed. For more information about grounding electrodes, see 250.52. In this section, different types of grounding electrodes are explained in detail. This article describes the one found at 250.52(A)(5). See language below and Figure 4. The answer is: “Yes, no and not so fast.” It is necessary to have a thorough understanding of the NEC to understand where these 5-foot floor bars are permitted and under what specific circumstances. Well, here`s the information you`ve all been waiting for.
Where can I find this “member only, strictly classified” information where I can install a 5-foot grounding rod? I`m tired of driving 8-foot floor posts into the ground. This information could save me years of back and shoulders, not to mention money. Would it be that simple? Is there a place where I can install shorter grounding rods for my electrical service? Note: Most local governments and local energy companies require the 2-foot rod method to pass the inspection. Some counties also allow or require a foundation or foundation floor connection for new construction. These are grounding electrodes that must be installed if necessary. If installers choose to use rod, tube or plate electrodes because there are no electrodes, only one electrode must be supplemented with an additional electrode of a type specified in paragraphs 250.52(A)(2) to (A)(8). The auxiliary electrode can be connected to the rod, tube or plate electrode; the conductor of the grounding electrode; the grounded department head; a non-flexible running track on the ground; or a grounded service enclosure. The NEC recognizes this challenge and offers alternatives if the electrode cannot be driven due to an impact on bedrock. The first step in this hierarchy of alternatives is to install the electrode at an angle not exceeding 45 degrees from the vertical. Often, this solves problems with the installation of grounding rods. (3) In buildings or structures without intersystem terminations or grounding devices.
If the service building or structure does not have an inter-system connection termination or grounding device as described in 800.100(B)(2), the grounding electrode conductor shall be connected to one of the following connections: While researching the history of the NEC, I also discovered that the first length of 8 feet indicated for a grounding rod is in the NEC of 1940. In the 1937 NEC, there was language for acceptable grounding electrodes at 2571 for water pipes and 2572 for artificial grounding. The text here refers to an artificial floor as a person whose electrode consists of a driven tube, rod, buried slab, or other device approved for that purpose.