Grounded Conductors On Panel Board Terminals

[north star]

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I am having a discussion with an electrical contractor, regarding the number of conductors

that can be installed in / under each setscrew [ in the panel boards ].

He says that more than one can be installed, as long as that particular panel board

manufacturer allows it. I am saying / thinking that Article 408.41 [ in the `08 NEC ]

limits the total number of conductors to just one. The Exception to Article 404.81 seems

to allow more than one grounded conductor under the setscrew, but the conductor cannot

be damaged or overtightened [ refer to Article 110.3(B) & 110.14 ]

I seem to recall us having a discussion about this very topic recently on here...

Your input is requested!



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[peach]

408.41 allows one and one only. The exception is for parallel conductors which per 310.4 would be 1/0 min

thanks Greg

 

[north star]

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Thank you peach [ and Greg ]!



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[Iowa49]

Some panel manufacturers do allow more than one, usually up to three of the same size, grounding conductors in the same terminal. Only one grounded conductor is allowed to terminate in each terminal.

 

[north star]

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Iowa49,

I am unclear as to what you are stating. Can you please clarify?

Thanks!



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[fatboy]

Equipment Grounding Conductors, multiple OK (based on Man.) vs. Grounded conductors, one allowed.

 

[480sparky]

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.

Pretty much says one neutral per terminal.

 

[EPrice]

Lets make sure we are all clear on the terminology here.

Grounded conductor, commonly referred to as the neutral: One allowed per screw per 408.41 as referenced by peach and 480sparky.

Grounding conductor, or equipment ground (bare or green conductor): One or more conductors per screw as allowed by the equipment manufacturer. The limiting factor here is the conditions of listing of the terminals.

 

[north star]

* * *

Thank you all for your input!

In this one particular application, the Elec. Contractor has two neutrals under one

set screw [ on one side of the panel board ], and two bare conductors under each

set screw [ on the other side of the panel board ]. His reasoning is ' the

manufacturer allows it '. Is this a true statement? Can he install multiples?

a) What about isolating that particular branch circuit when more than one neutral

is connected to the same terminal? b) Is this a correct install - - one neutral

only, per 408.41, but more than one, but no more than three "equipment grounding

conductors" are allowed per 408.41, or more than one neutral, per the

manufacturer of the panelboard and more than one "equipment grounding

conductor"?

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[480sparky]

Let him produce the documentation from the manufacturer that 'allows it' if he wants to get it past the inspector.

I think 408.41 is pretty plain..... when terminating a grounded conductor, it will be by itself.

 

[north star]

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Agreed 480 sparky!

Is this a common allowance by [ some ] panel board manufacturers?

I see a lot of it `round these parts.

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[480sparky]

I've never known a panel to allow it. At least on the grounded (neutral) conductors.

Some makers allow two ungrounded (hots) on the breaker, but that's a different story.

 

[raider1]

I've never known a panel to allow it. At least on the grounded (neutral) conductors.Some makers allow two ungrounded (hots) on the breaker, but that's a different story.

I agree, I have never seen a modern panelboard that has installation instructions that permit multiple grounded conductors to be installed under 1 screw.

Chris

 

[peach]

well, that.. and why would you want to? If there are that many circuits, you need to re-think what you are doing. Just saw one this week... lots of open screws.. no reason. Lazy electrician?