Grounded Conductor & Equipment Grounding Conductor

[dtontarski]

I apologize if this topic has been covered to death...

I often see grounded conductors and equipment grounding conductors under single terminals on the terminal bars in the service panel. Is this allowable? I thought I recently followed a thread that discussed this, but I couldn't find it again. If this is not allowable - can anyone provide me the code reference?

[dtontarski]

Found it...great search engine....I keyed in "grounded neutral conductor" and a post which began in 09/2005 titled "Need Electrical Code" returned with the information I needed. I knew I saw it before. It's a good read for anyone interested. But, it still doesn't site any code around this topic. I'm still interested in input. Thanks.

[Bob White]

NEC 2005 408.40 Grounding of Panelboards ... Grounding conductors shall not be connected to a terminal bar provided for grounded conductors (may be a neutral) unless the bar is identified for the purpose and is located where interconnection between equipment grounding conductors and grounded circuit conductors is permitted or rquired by Article 250.

408.41 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.

For information on parallel conductors and where they are permitted, you must go to Article 310.4. That article permits parallel conductors smaller that 1/0 under certain circumstances. None of those circumstances are likely to me met in a residential panelboard.

[Jim Katen]

Originally posted by dtontarski

I apologize if this topic has been covered to death...

I often see grounded conductors and equipment grounding conductors under single terminals on the terminal bars in the service panel. Is this allowable? I thought I recently followed a thread that discussed this, but I couldn't find it again. If this is not allowable - can anyone provide me the code reference?

It's a very minor issue, but it's not ever been allowed by the NEC.

UL 67 has always required the one-neutral-per-terminal rule in all class CTL panels, but the NEC has only specifically articulated that requirement since 2002.

408.41 is the current reference. Before that, it was 110.3(B) (accordance with listing & labeling).

- Jim Katen, Oregon

[dtontarski]

Just to make sure that I have a good grasp on this - equipment grounding conductors and grounded conductors should not be on the same terminal, but this is a minor issue. (the thread I cited explains the issues associated with this). It seems like 90% of the panels I inspect have this condition.

How should I address this? To date I have cited that grounded neutral conductors should have there own separate terminals and that equipment grounding conductors should not be on terminals with grounded neutral conductors.

At this moment I have a local electrician (I inspected his dad's home (the seller) and cited this and a few other things) is getting all pissy with me. He's saying that grounded neutral conductor is not even and electrical term...funny, it's in Doug Hansen's Book, and saying saying I don't know what I'm talking about. Any advice out there on this?

[Bob White]

Originally posted by dtontarski

Just to make sure that I have a good grasp on this - equipment grounding conductors and grounded conductors should not be on the same terminal, but this is a minor issue.

Article 90.1 of the NEC sez. "This Code contains provisions that are considered necessary for safety." Call it minor if you wish, but is is the minimum standard.

(the thread I cited explains the issues associated with this).

I believe the major issue is that the UL and NEC folks really want the grounding condutor to remain intact while the circuit (line and neutral) are disconnected to isolate a circuit.

How should I address this? To date I have cited that grounded neutral conductors should have there own separate terminals and that equipment grounding conductors should not be on terminals with grounded neutral conductors.

At this moment I have a local electrician (I inspected his dad's home (the seller) and cited this and a few other things) is getting all pissy with me. He's saying that grounded neutral conductor is not even and electrical term...funny, it's in Doug Hansen's Book, and saying saying I don't know what I'm talking about. Any advice out there on this?

I call them "grounding conductors (grounds)" and "grounded conductors (neutrals)" the first time I mention them, and refer to them as grounds and neutrals thereafter. As for your electrician, refer him to code, or, since he hasn't paid you for any information, ignore him.

[dtontarski]

Bob -

Thanks for your review and thoughts on this. I think I will follow suit on how you reference these terms - professional definitions first, but grounds and neutrals is how most folks refer to these. One small gain in report writing efficiencies (and clarity) at a time. Thanks again.