Need electrical code

[Tom Rollins]

I need some help here from some wise old electrician or wise old code inspector. I need a code from the NEC that will back up my statement in my report saying: “A double wire (two wires or more under a single lug) exists within the panel on the grounded neutral conductors.â€

[hausdok]

Hi Tom,

I owe you an apology. You'd posted this in the wrong place under the 'post a new article for submission to TIJ' and I didn't see it because it was during the time I went back east to bury my little sister.

Doubtless, you've probably got your answer by now, but I've moved it over here to the electrical forum so that you can get it answered anyway. By the way, this particular issue has been discussed many times here and can probably be found by searching the previous posts in this particular forum category.

Shooting from the hip, the builder is full of it up to his eyebrows, unless (There's always an exception to everything, it seems.) the breaker is designed and approved for use with more than one conductor. Square D and one other manufacturer whose name escapes me at the moment make these.

So, if the breakers were one of these two particular types and are approved for use in that particular panel and no more than two conductors are being used for each, his eyebrows wouldn't be so encrusted.

ONE TEAM - ONE FIGHT!!!

Mike

[hausdok]

Okay,

It's early morning and I just got up and moved this post. Now that I've re-read it, I notice that you said that your talking about grounded neutral conductors, so it looks like you aren't referring to breakers but are referring to the practice of placing more than one conductor under the same lug at the neutral bus - not at a breaker. If that's the case, consider the builder once again encrusted, because grounded (neutral) conductors may not be doubled under a single lug in the panel. Here's what one code body says:

2002 NEC 408.21 Grounded Conductor Terminations.

Each grounded conductor shall terminate within the panelboard in an individual terminal that is not also used for another conductor.

Exception: Grounded conductors of circuits with parallel conductors shall be permitted to terminate in a single terminal if the terminal is identified for connection of more than one conductor.

Here's some further discussion on the topic:

Log from the NEC Code Panel, regarding the new clarifying language in the Code.

(Log #3287) 9- 113 - (384-21 (New) ): Accept

SUBMITTER: James T. Pauley, Square D Co.

RECOMMENDATION: Add a new 384-21 to read as follows:

384-21. Grounded Conductor Terminations. Each grounded conductor shall terminate within the

panelboard in an individual terminal that is not also used for another conductor. Exception: Grounded conductors of circuits with parallel conductors shall be permitted to terminate in a single terminal if the terminal is identified for connection of more than one conductor.

SUBSTANTIATION: This revision is needed to coordinate the installation requirements with a long standing product standard requirement. Clause 12.3.10 of UL 67 (Panelboards) states “An individual terminal shall be provided for the connection of each branch-circuit neutral conductor.â€

[Richard Moore]

In addition to Mike's answer, the other piece of code you could refer to is is the last sentence of 110.14(A)...

"Terminals for more than one conductor and terminals used to connect aluminum shall be so identified."

That section is, I believe more about the quality of the connection, rather than the "isolating circuits" issue. A simple set screw in a round lug may or may not be applying sufficient pressure on both wires. No sure way to tell. The "double-tap allowed" Square-D (and CH) breaker terminals are designed specifically to spread that pressure equally on both conductors if two are installed. It is my understanding that 2 (or 3) grounding (but not grounded or neutrals) conductors are allowed (when identified on the panel) under neutral/ground terminals because any current they might carry would only be momentary before the OCPD trips.

Either way, the builder is wrong.

[Tom Rollins]

Thanks Mike and Richard for the information. Sorry about your little sister Mike, my condolence to you and your family. Apology accepted. I was able to obtain this information form an electrical contractor. Sorry I was not able to reply before now. Thank you both for the effect.

Tom