Note that per NEC 362.6, ENT and associated fittings shall be listed see Electrical Nonmetallic Tubing Fittings (FKKY) on UL Product iQ (UL.com/piq). On this project, listed raceway connections from electrical nonmetallic tubing (ENT) to conduit fittings embedded in these slabs were used. Junction boxes may be used for splice points, floor receptacles, lighting outlets, as well as for data and communications. First, verify the separation of power circuits and emergency circuits as required by NEC 700.10.Īnother area of concern is the placement of junction boxes. Electrical nonmetallic tubing (ENT) rough-in ready for concrete.Īs the floors are being constructed, close attention is required to the layout locations for the electrical equipment, devices, and proposed conduit routing. Exothermic weld conductor splice within the concrete wall section. All of these runs were interwoven through the rebar within the building structure and not in raceways. While checking this particular installation, remember to verify that all are continued up to the intended locations. These also are installed up to the roof for connection to the air terminals. Size 3/0 AWG braided copper conductors are used for the connections as required by NEC 250.106. The lightning protection system was connected to the common grounding electrode conductor via the exothermic welding process. The generator and load bank are also connected to the common grounding electrode. By using this grounding and bonding riser system, we can connect all of the metallic piping and exposed structural steel required to be bonded by NEC 250.104. On the third floor, there are connections for the data server room and the battery backup system. On each floor, there are exothermic welds and incorporated ground bus bars for two electric rooms and two data communication rooms. This conductor was then installed up to the service located on the ground floor and continued up to the roof for the common grounding electrode conductor. This is not to be confused with a ground ring, which is to be in direct contact with the earth. The conductor was bonded to the rebar ( NEC 250.50 & 250.52) and was placed on top of a moisture retention layer of a concrete slurry seal. For this structure, the engineer chose to install a 3/0 AWG conductor ( NEC 250.66) around the entire perimeter down in the bottom under the foundation slab ( NEC 250.64). Let us start with the grounding electrode conductor. I’ve also checked the 2011 requirements against the 2020 edition and made any updates as necessary. This installation was originally reviewed per the 2011 National Electrical Code (NEC) and other applicable codes. We will show you both the complexity of the service and the simplicity of the receptacles. We will start at the bottom with the concrete-encased electrode (Ufer) and go all the way up to the first cup of coffee. This article will take you through the electrical construction of a nine-story high-rise structure with parking at three floors down and four floors up.
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