concrete encased duct bank bare ground sizing

#CONCRETE ENCASED DUCT BANK BARE GROUND SIZING MANUAL#
#CONCRETE ENCASED DUCT BANK BARE GROUND SIZING CODE#

Ufer confirm the validity and reliability of concrete-encased electrodes. The issue of the word “available” being replaced with the term “if installed and present” is a concept that definitely is in need of further review. The word “available” relative to the coordination of installation concrete encased electrode is a matter of a point in time when the building is being constructed.

#CONCRETE ENCASED DUCT BANK BARE GROUND SIZING MANUAL#

The word “available” is not enforceable and according to the NEC Style Manual for 2000 should be avoided. Sometimes, depending on how the section is interpreted, the word “available” and the word “existing” work against one another.

#CONCRETE ENCASED DUCT BANK BARE GROUND SIZING CODE#

The Code requires that if an electrode is available, then it must be used as part of the grounding electrode system. As used in Section 250-50, the word “available” can lead to inconsistency. Most entities involved in the electrical industry, either as electrical contractors, designers, engineers or inspectors, agree that it is important to inspection departments and jurisdictions to strive for the most consistency and uniformity possible when enforcing the requirements of the Code. Reinforcing bars shall be permitted to be bonded together by the usual steel tie wires or other effective means.1 (12.7-mm) diameter, or consisting of at least 20 ft (6.1 m) of bare copper conductor not smaller than No. (50.8 mm) of concrete, located within and near the bottom of a concrete foundation or footing that is in direct contact with the earth, consisting of at least 20 ft (6.1 m) of one or more bare or zinc galvanized or other electrically conductive coated steel reinforcing bars or rods of not less than ½-in. The concrete-encased electrode is described in Section 250-50(c) of the NEC, which reads: The concrete-encased electrode is often referred to as a Ufer ground, although the word “Ufer” does not appear in the text of the Code. An effective, reliable grounding electrode or grounding electrode system is required to be used where electrical services and systems are employed. The grounding electrode system is the foundation of the electrical safety system. The grounding electrodes required to be used make up the grounding electrode system and are required to do so because they are inherent to the construction of the building. Electrical systems and metal enclosures are grounded to limit the voltage on them due to contact with higher voltage lines protect against lightning strikes and to stabilize the voltage during normal operations. The lowest possible impedance connection to the earth is sought from the grounding electrode or grounding electrode system. This is a characteristic of the building footings and foundation that are expected to be in place and continue to exist as long as the building is required to remain standing.Ī grounding electrode is defined as a conducting element that connects electrical systems and/or equipment to the earth. The word “permanent” is a substantial word related to something established to be in place for a long period of time. These structures have some commonalities both include concrete and reinforcing bars, which establish a good structural connection to the earth and are permanent elements required for the construction of either building. An example would be comparing a simple monolithic slab on grade for a single-family dwelling to a complex concrete and steel foundation for a multi-story high-rise structure. Concrete footings and foundations can vary from the elementary in design to the very complex.

The larger the building, the larger the footings or foundation will need to be to carry the structural load of the building. Footings and foundations are typically constructed using concrete and reinforcing rods or bars for structural strength. For the building to be structurally sound and stable, a substantial foundation must be established to bring the structure out of the ground. Most buildings or structures employ a structural design that includes a concrete footing or foundation, which connects the structure to the earth.

Concrete encased duct bank bare ground sizing