I believed that the "only one conductor per terminal" rule was all-encompassing, but in reading 110.14(A) Terminals (2002NEC), it mentions "Terminals for more than one conductor...shall be so identified".

One of my co-workers says that when wiring in a main panel, he terminates the grounded conductor and the grounding conductor of the same circuit under the same screw on the terminal bus, if there are no separate GND and NEUT bars.

Is he complying with the NEC in diong this?

Are terminal bars in breaker panels "identified" or rated (listed) for two conductors under each terminal (screw)?

Started doing this myself, but, not sure of the integrity of both wires having same pressure, and remaining securely attached.

I rarely run Romex, but when I do I have put the neutral and ground under the same screw. I'm a little bleary-eyed to look it up now, but my feeling on the matter is that the neutral and ground are bonded at the service and the terminal is plenty large enough.

Where I see it that is definitely wrong is on the line side of the main breaker.

Dave
(edited for spelling)

[This message has been edited by Dave55 (edited 10-24-2004).]

408.21 tells me you can't do it.

Each grounded conductor shall terminate within the panalboard in an indivdual terminal that is not used for another conductor.

I agree with Sparky and would add that there are panels in use out there that are Listed and permit the "grounding" conductor to be terminated under the same screw with other "grounding" conductors and the combinations are clearly indicated in the spec sheet inside the panel. I know of no panels that allow the connection of the grounded and grounding conductor under the same screw.

I agree that placing the bare and white wires under the same screw is a bad ides- even though it makes for a neater panel.
What you can do, however, is twist as many as three bare wires together, then place them under one screw.
Of course, it's not that hard, or expensive, to add a ground bar.

I've not seen a panel where the listing allows for more than 2 ground wires under 1 screw. # would be a violation of the listing in most cases.

Look at the Cutler-Hammer CH series (and I think the BR series too). They can accomodate up to three #10-#14 grounding wires in a single hole. Must be the same type of wire in each hole.

CH breakers are also listed for 2 wires in each hole when small wires (#10 - #14 I believe) are used.

CH is great with providing all of the important listing information you need stamped on their breakers and panels.

The rule is pretty simple. You can do what the listing allows. I think you would assume 1 wire per screw unless specifically listed for more.