How well do you know the Code? Think you can spot violations the original installer either ignored or couldn't identify? Here's your chance to moonlight as an electrical inspector and second-guess someone else's work from the safety of your living room or office. It's your turn to identify the violation.
Hint: If three’s a crowd, what’s four?
Find the Answer
After looking at the black, red, and blue phase wires feeding this panel, you should be able to easily spot the Code violation. Four wires connected to a lug designed for only two is a direct violation of Sec. 110.14(A), unless the terminals are specifically identified for that purpose. When you look at the neutral lugs, you see the same problem — two wires connected to a single barrel lug.
Connecting wires in this manner can result in a poor connection at the terminal, which, in turn, can cause a loose arcing connection or a connection that crushes the wires and causes a “hot spot” to develop. Either situation could eventually cause the connection to fail and burn up, resulting in damaged equipment or worse.
Section 408.41 similarly requires grounded conductors to terminate within the panelboard on individual terminals that are not used for another conductor. The Exception would permit paralleled grounded conductors to terminate on a single terminal if it is identified for connection of more than one conductor. The minimum wire bending space required at the terminals may also have been violated since Sec. 312.6 has different dimensions required at terminals for one conductor, two conductors, three conductors, and so forth.