Brick by Brick
This electrical metallic tubing (EMT) runs more than 75 ft from a main distribution panel located at the rear of a commercial store in a downtown area. There were no required supports along the entire run — outside of this beautiful red brick.
Article 358 covers the requirements for EMT. As noted in 358.12, “EMT shall not be used, where, during installation or afterward, it will be subject to severe physical damage.” More importantly, Section 358.30 states, “EMT shall be installed as a complete system in accordance with 300.18 and shall be securely fastened in place and supported in accordance with 358.30(A) and (B).” As per 358.30(A), “EMT shall be securely fastened in place at least every 3 m (10 ft). In addition, each EMT run between termination points shall be securely fastened within 900 mm (3 ft) of each outlet box, junction box, device box, cabinet, conduit body, or other tubing termination.”
So Close, Yet So Far Apart
This PVC raceway for service lateral conductors has come apart at the connector because it was not designed with the correct transition or expansion fitting. As noted in 300.5(J), “Where direct-buried conductors, raceways, or cables are subject to movement by settlement or frost, direct-buried conductors, raceways, or cables shall be arranged so as to prevent damage to the enclosed conductors or to equipment connected to the raceways.” An Informational Note adds, “This section recognizes ‘S’ loops in underground direct burial to raceway transitions, expansion fittings in raceway risers to fixed equipment, and, generally, the provision of flexible connections to equipment subject to settlement or frost heaves.”
The “floating” grounding electrode conductor to the left of the raceway is also worth addressing. As per 250.64(B), "Where exposed, a grounding electrode conductor or its enclosure shall be securely fastened to the surface on which it is carried." Grounding electrode conductors shall be permitted to be installed on or through framing members. A 4 AWG or larger copper or aluminum grounding electrode conductor shall be protected if exposed to physical damage. A 6 AWG grounding electrode conductor that is free from exposure to physical damage shall be permitted to be run along the surface of the building construction without metal covering or protection if it is securely fastened to the construction; otherwise, it shall be protected in rigid metal conduit (RMC), intermediate metal conduit (IMC), rigid polyvinyl chloride conduit (PVC), reinforced thermosetting resin conduit (RTRC), electrical metallic tubing (EMT), or cable armor. Grounding electrode conductors smaller than 6 AWG shall be protected in RMC, IMC, PVC, RTRC, EMT, or cable armor.”