Illustrated Code Catastrophes: Article 358, Section 300.5 and 250.64

More Code catastrophes uncovered in these faulty installations

More Code catastrophes uncovered in these faulty installations

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.”

Discuss this Article 3

Anonymous (not verified)
on Aug 28, 2012

Doesn't a #4 awg fall under the exact same category as a #6 awg? Both require conduit if exposed to physical damage. Assumption: all gec conductors larger than #8 can be run on surface without conduit if not exposed to physical damage. It appears repetitive and confusing.

Jose A. Guillen (not verified)
on Sep 29, 2012

it is a judgment call if you knowingly see its location. Think if it is exposed to damage yes protect it but if it is secured correctly and not in the path of being damaged yes it doesnot have to be encased or protected that is what the code is trying to say my friend.

Anonymous (not verified)
on Oct 11, 2012

"4 AWG or larger copper or aluminum grounding electrode conductor" doesn't even need to be mentioned. The reason #4awg is mentioned is because in the 2002 Nec a #4awg only required protection when exposed to"severe" damage, the word "severe" was taken out in 2005. The whole sentence should have been taken out. This is interpreted differently by local AHJ's.

Post new comment
Sign In or register to use your Electrical Construction & Maintenance (EC&M) Magazine ID
(optional)

White Papers
EC&M Learning Center
Webinars
EC&M TV
Apr. 15, 2013
video

The Westex Difference

Learn what sets Westex apart from other flame resistant fabric manufacturers....More

Newsletter Signup

Connect With Us