Thread: can ground and neutral be double taped at panel

This is what I have found in the panel today this is a main panel, Outside. The Grounds and Neutrals are double tapped (with each other). Would this have the same potential problems as double tapped neutrals. I just have not seen it done this way before. Square D panel, house built 2001.

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EGC's can sometimes be terminated 2 or 3 conductors to a slot if the bar is so listed. Neutral conductors require their own individual termination point.

Originally Posted by Robert Meier

EGC's can sometimes be terminated 2 or 3 conductors to a slot if the bar is so listed. Neutral conductors require their own individual termination point.

That is what i was thinking. the grounds and neutrals kind of threw me. But your clarification of the Neutrals requireing their own termination answers that.
Thanks a bunch!

Here's an old graphic but it's content is still applicable.

If this is trluy the "main" (contains the main disconnecting means) then having the equipment grounds and neutrals on the same bar is okay. However, the neutrals and the grounds are typically not mixed under the same terminal screw. If you look at the decal inside the panel for the termination torque requirements it typically shows only a single wire for the neutral torque specs, whereas the equipment ground specs usually allow 2 or 3 wires terminated under the same screw terminal. I don't believe that the 1999 NEC specifically prohibited the practice like to more recent NEC codes do. You can search Art. 384 and see if you find anything. But even if not specifically prohibited, the manufacturer usually doesn't allow it.

"can ground and neutral be double tap(p)ed at panel"

The answer to that specific question is yes.

A different question (should they / are they permitted to be double tapped?) would have a different answer.

I don't mean to be annoying about this but it's an example of being specific in your choice of words and phrasing. A primary way of reducing your liability is being cautious in how you write and communicate.

Originally Posted by Robert Meier

Here's an old graphic but it's content is still applicable.

You did identify this as an old graphic.

I would direct you to Article 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."

That article is from the 2008 NEC which is the edition currently recognized by the state of New York.

If you utilize the 2008 NEC Handbook, an explanation follows that indicates that you can terminate two conductors under a terminal so identified as suitable for such, however; I do not believe that the "explanation" from the handbook is quotable for citing a percieved defect.

Additionally, I have always been informed that a manufacturer's instructions superceded code.

So.....in conclusion, I would say that the answer is both yes and no and is entirely dependent on the inspector's perception of the article in the literal sense.

I agree with the illustration provided except that these examples are from the more recent 2002-2008 NEC. The requirements of Art. 408 did not exist in 2001. In the 1999 NEC Handbook there is no specific prohibition of the installation as shown in the photograph. The handbook defaults to the manufacturer or listing as the prevailing factor. At 110-14(a) it states:".....Terminals for more than one conductor and terminals used to connect aluminum SHALL BE SO IDENTIFIED." In other words, unless the manufacturer identifies the terminal for use with multiple conductors, it should not be done. That information must be obtained from the Branch Neutral and Equipment Ground Table which is found within the panel enclosure. If the torque requirements do not show more than one conductor (as in the illustration from the more recent handbook) then it is incumbent upon the installer to land each neutral under an indivdual terminal screw. As you can see in the table within the illustrations, the manufacturer in that case allows two wires on terminals for equipment grounds only. Many manufacturers allow multiple conductors for equipment grounds but not for neutral conductors. Actually, I've never inspected one that allowed for multiple wires for neutral terminations.

Originally Posted by Keith Gipe

I agree with the illustration provided except that these examples are from the more recent 2002-2008 NEC. The requirements of Art. 408 did not exist in 2001. In the 1999 NEC Handbook there is no specific prohibition of the installation as shown in the photograph. The handbook defaults to the manufacturer or listing as the prevailing factor. At 110-14(a) it states:".....Terminals for more than one conductor and terminals used to connect aluminum SHALL BE SO IDENTIFIED." In other words, unless the manufacturer identifies the terminal for use with multiple conductors, it should not be done.

While the specifically stated requirement did not exist before then, the requirement still DID exist before then. The difference is that the requirement before then simply stated that it had to be installed as listed and labeled, and no terminals were listed or labeled for more than one NEUTRAL conductor (at least I have never seen any listing or labeling which stated that a terminal was listed for more than one NEUTRAL conductor).

All the code did was make it easier for installers to understand: instead of stating that the terminals had to be installed and used as listed and labeled, and making the installers search out that listing and labeling (it is likely that few did search that out), the code was changed to state DON'T TERMINATE MORE THAN ONE NEUTRAL in a terminal. It's called the KISS principle.

I've seen this before when a house was getting its final building inspection by a building inspector. The rule was one screw/one wire. Two neutral wires can be wire nuted to one pigtail to allow two circuits connected to one screw on the buss. Three or four ground wires can be wire nuted to one pigtail to use one screw on the buss. You can actually free up more screws on the buss then you need. On the other hand, I've heard wire nuts are not allowed in main panels in some states. Don't know for sure. I've been doing home construction in wisconsin for the past fifteen years and have never seen a main panel fail inspection due to wire nuts. I recently aquired my HI license and am in the process of starting up my new business.

Originally Posted by Mike Borchardt

I've seen this before when a house was getting its final building inspection by a building inspector. The rule was one screw/one wire. Two neutral wires can be wire nuted to one pigtail to allow two circuits connected to one screw on the buss. Three or four ground wires can be wire nuted to one pigtail to use one screw on the buss. You can actually free up more screws on the buss then you need. On the other hand, I've heard wire nuts are not allowed in main panels in some states. Don't know for sure. I've been doing home construction in wisconsin for the past fifteen years and have never seen a main panel fail inspection due to wire nuts. I recently aquired my HI license and am in the process of starting up my new business.

The only way you could do this is if the two circuits were not on the same phase otherwise you could overload the pigtail.

Originally Posted by Mike Borchardt

I've seen this before when a house was getting its final building inspection by a building inspector. The rule was one screw/one wire. Two neutral wires can be wire nuted to one pigtail to allow two circuits connected to one screw on the buss. Three or four ground wires can be wire nuted to one pigtail to use one screw on the buss. You can actually free up more screws on the buss then you need. On the other hand, I've heard wire nuts are not allowed in main panels in some states. Don't know for sure. I've been doing home construction in wisconsin for the past fifteen years and have never seen a main panel fail inspection due to wire nuts. I recently aquired my HI license and am in the process of starting up my new business.

Then either this was a written amendment, or they simply made that up. Multiple ground under a screw have been code legal for many years in pretty much every panel I have installed.

Originally Posted by Speedy Petey

Then either this was a written amendment, or they simply made that up. Multiple ground under a screw have been code legal for many years in pretty much every panel I have installed.

SP....not since 29 December 2010.

The date NYS adopted the 2008 NEC.

Prior to that, as JP stated, manufacturer's instruction regulated such.

I have never seen a neutral or ground bus, especially in a residential panel, come equipped with a "listed" means for doubling up under 1 screw! And, the busbar must be "listed" to be able to terminate in this manner! You are allowed to use a "wire-nut" to build a pigtail and then term under a screw!

Originally Posted by Don Gerjevic

I have never seen a neutral or ground bus, especially in a residential panel, come equipped with a "listed" means for doubling up under 1 screw! And, the busbar must be "listed" to be able to terminate in this manner! You are allowed to use a "wire-nut" to build a pigtail and then term under a screw!

Read the label!

MOST panels will allow the use of 2 *grounding* conductor per terminal!

!

You easily excited!

Originally Posted by Robert Meier

The only way you could do this is if the two circuits were not on the same phase otherwise you could overload the pigtail.

Not so. Common pratice was to use three conductor wire to feed and area with two circuits. A red, black, and white wire. The red and black were hot and the white is neutral. It didn't mater if the red and black were on the same phase with two breakers. However, you would not pigtail another neutral from a third circuit with this configuration.

Originally Posted by Robert Meier

The only way you could do this is if the two circuits were not on the same phase otherwise you could overload the pigtail.

Originally Posted by Mike Borchardt

Not so. Common pratice was to use three conductor wire to feed and area with two circuits. A red, black, and white wire. The red and black were hot and the white is neutral. It didn't mater if the red and black were on the same phase with two breakers. However, you would not pigtail another neutral from a third circuit with this configuration.

What does this have to do with your previous post where you stated that you could pigtail two neutral conductors and terminate the single pigtail in one hole on the bus?

Originally Posted by Mike Borchardt

I've seen this before when a house was getting its final building inspection by a building inspector. The rule was one screw/one wire. Two neutral wires can be wire nuted to one pigtail to allow two circuits connected to one screw on the buss. Three or four ground wires can be wire nuted to one pigtail to use one screw on the buss. You can actually free up more screws on the buss then you need. On the other hand, I've heard wire nuts are not allowed in main panels in some states. Don't know for sure. I've been doing home construction in wisconsin for the past fifteen years and have never seen a main panel fail inspection due to wire nuts. I recently aquired my HI license and am in the process of starting up my new business.

Originally Posted by Richard D. Fornataro

SP....not since 29 December 2010.

The date NYS adopted the 2008 NEC.

Prior to that, as JP stated, manufacturer's instruction regulated such.

Grounded conductors (neutrals, white wires) are both code and manufacturer limited to one wire per connection on a panel buss bar.

Grounding conductors, the wire that is either bare or green, have no maximum number per connection mandated by code, therefore the manufacturer's instructions prevail. GE's catalog shows that up to 3 #14, #12, or #10 can be terminated on the same position of SOME buss bars. Panel and/or buss bar labeling will dictate individual circumstances. This hasn't changed in the NEC.

One issue here is that it's possible that the original buss bar, the one that the panel label says is limited to 2 wires may have been replaced by one that allows 3. No sticker comes with the replacement bar to indicate the change.

All of this, of course, absent any local amendments.

It should be pretty obvious that the buss bars are able to handle more than one neutral per terminal. The practice is prohibited to prevent the unintentional disconnection of an in-use neutral, especially one on a multi-wire circuit, when removing another. Of course, you shouldn't be working the panel hot anyway.

As to pig tailing 2 or more neutrals to make a neutral buss connection,
2011 NEC 200.4 Neutral Conductors.
Neutral conductors shall not be used for more than one branch circuit, for more than one multiwire branch circuit, or for more than one set of ungrounded feeder conductors unless specifically permitted elsewhere in this Code.

Originally Posted by Mike Borchardt

Not so. Common pratice was to use three conductor wire to feed and area with two circuits. A red, black, and white wire. The red and black were hot and the white is neutral. It didn't mater if the red and black were on the same phase with two breakers. However, you would not pigtail another neutral from a third circuit with this configuration.

Mike,

It's possible I am misinterpreting what you wrote but as I read it, it is completely wrong.

When you use a three conductor cable to feed branch circuits, you CANNOT land red and black conductors on the same phase under ANY circumstances.

A 20A circuit red wire landed on the same phase as a 20A circuit black wire is not allowed.

The result would be additive, therefore increasing the possible current on the neutral (white) conductor to 40A, which would exceed the allowable ampacity of a 12 ga. solid copper conductor used in a residential branch circuit.

You must therefore land the red and black conductors on different phases so that the load placed on the neutral conductor is not additive.

This comment is not meant to criticize, merely to educate.

If anyone needs further explanation of the theory behind these statements, please ask.

Originally Posted by Bill Kriegh

Grounded conductors (neutrals, white wires) ...

As to pig tailing 2 or more neutrals to make a neutral buss connection,
2011 NEC 200.4 Neutral Conductors.
Neutral conductors shall not be used for more than one branch circuit, for more than one multiwire branch circuit, or for more than one set of ungrounded feeder conductors unless specifically permitted elsewhere in this Code.

Bill,

Keep in mind that you are referring to two different things there and that it is easy to unintentionally interchange the two terms when that distinct difference rears its ugly head ... I make the same mistake too ...

- Neutral Conductor. The conductor connected to the neutral point of a system that is intended to carry current under normal conditions.

- Grounded Conductor. A system or circuit conductor that is intentionally grounded.

a) Can you pigtail the "grounded" conductor of more than one circuit into a wire connector and make it one "grounded" conductor?

b) Can you pigtail the "UNgrounded" conductor of more than one circuit into a wire connector and make it one "UNgrounded" conductor?

What difference is there between doing a) or b)?

The "neutral" conductor is a completely different animal than the "grounded" conductor, even though the term "neutral" is commonly used when referring to a "grounded" conductor which is not a "neutral".

Originally Posted by Jerry Peck

Bill,

Keep in mind that you are referring to two different things there and that it is easy to unintentionally interchange the two terms when that distinct difference rears its ugly head ... I make the same mistake too ...

- Neutral Conductor. The conductor connected to the neutral point of a system that is intended to carry current under normal conditions.

- Grounded Conductor. A system or circuit conductor that is intentionally grounded.

a) Can you pigtail the "grounded" conductor of more than one circuit into a wire connector and make it one "grounded" conductor?

b) Can you pigtail the "UNgrounded" conductor of more than one circuit into a wire connector and make it one "UNgrounded" conductor?

What difference is there between doing a) or b)?

The "neutral" conductor is a completely different animal than the "grounded" conductor, even though the term "neutral" is commonly used when referring to a "grounded" conductor which is not a "neutral".

Under normal conditions in a (US) residence, all neutrals are grounded conductors but not all grounded conductors are neutrals. They do, however by common usage, refer to the same thing. Both wires terminate on the same buss. Different rules apply in some instances.

The difference is pretty significant if you:

do only a), you now have either a multi wire circuit (you make the grounded conductor into a neutral ) OR 2 circuits sharing an undersized grounded conductor (unless you up-sized the pigtail). If on 2011 code new rules now apply (tie bar on breakers and somehow indicating which wires are involved with that particular circuit if the breakers are on different busses.

b) is pretty common, and usually legal (except, apparently, in Boulder CO, among other possible places) IF you don't put a load on the breaker in excess of its' ratings ( the 2 circuits essentially now become one circuit and according to the NEC circuits have to be sized to the loads anticipated


However, the a) + b) winds up also being b)

Originally Posted by Bill Kriegh

Under normal conditions in a (US) residence, all neutrals are grounded conductors but not all grounded conductors are neutrals.

Precisely why one does not apply a code section regarding neutrals to grounded conductors.

In fact, under normal conditions on a 120 volt branch circuit, the grounded conductor is *not* a neutral.

Applying a code section regarding grounded conductors to neutrals is, as you implied, almost always correct.

That code section was regarding neutrals, thus it is not automatically applied to every white grounded conductor.

They do, however by common usage, refer to the same thing.

By common usage, yes, but not by the specificity of the code referring to neutrals ... the code does not refer to items "by common usage".

Both wires terminate on the same buss. Different rules apply in some instances.

In many instances.

The difference is pretty significant if you:

do only a), you now have either a multi wire circuit (you make the grounded conductor into a neutral ) OR 2 circuits sharing an undersized grounded conductor (unless you up-sized the pigtail). If on 2011 code new rules now apply (tie bar on breakers and somehow indicating which wires are involved with that particular circuit if the breakers are on different busses.

b) is pretty common, and usually legal (except, apparently, in Boulder CO, among other possible places) IF you don't put a load on the breaker in excess of its' ratings ( the 2 circuits essentially now become one circuit and according to the NEC circuits have to be sized to the loads anticipated


However, the a) + b) winds up also being b)

You lost me in your "if you do only a)" as you are not doing anything, however, I believe I understand what you were trying to say - something like this:
The difference is pretty significant if you:

a) have a multiwire circuit (you make the grounded conductor into a neutral)

b) have 2 grounded conductors pigtailed to a single grounded conductor of the same size, you now have one circuit with a grounded conductor which is still properly sized for the breaker provided that the respective ungrounded conductors are likewise terminated on one breaker

Other than what I've posted above, you lost me - not sure if it is just me missing something in your wording, or if it is something in your wording which is missing or unintended???

I don't know much 'bout that darn 'lectricity stuff, so you will need to 'splain it to me better.

I do know that when you let the smoke out of the circuit that things quit working, so that 'lectricity stuff much somehow involve 'smoke' ... how do I put the smoke back in to git it workin' again?

Ever so sorry but I guess I am on drugs after reading all of these posts.

Please go back to "Definitions", with respect to the 2008 or 2011 editions of the NEC and answer these simple questiions!

Define a "Branch Circuit"

What purpose does the White, Gray, or Black (with three vertilcal white lines) conductor serve?

An "Ugrounded" conductor (line to Neutral), does what?

An "Intentionaly Grounded" conductor, does what?

An "Equipment Grounding", conductor, does What?

In a three phase system, what is the "Neutral Point"?

The NEC added the definition of neutral conductor to get rid of the argument that there is actually a difference between a neutral and a grounded conductor. If it's connected to the neutral point of the system it's, by NEC definition, a neutral. Doesn't matter if it's a two wire or a MWBC.

While it is permissable to double tap bare ground conductors, the same is not true of the "Neutral or Return" conductor.

The White, Gray or Black with 3 white vertical conductors, cannot be double tapped, nor can they be pigtailed onto one conductor.

Think about that. Say you had two 20 amp branch circuit returns tapped onto one conductor. Both of these conductors are carrying return current. How much current is being carried on the conductor from the splice to the return bus?

Originally Posted by Robert Meier

The NEC added the definition of neutral conductor to get rid of the argument that there is actually a difference between a neutral and a grounded conductor. If it's connected to the neutral point of the system it's, by NEC definition, a neutral. Doesn't matter if it's a two wire or a MWBC.

Robert,

That is one of those DUH! (said as he slaps forehead with hand) moments we get now and then, some refer to them as 'senior moments' ... *I* post the definition of "neutral conductor" and *I* blew right through what it said ...

Originally Posted by Jerry Peck

- Neutral Conductor. The conductor connected to the neutral point of a system that is intended to carry current under normal conditions.

Criminey, what will I miss next? Me bad.

Originally Posted by Donald Farrell

Think about that. Say you had two 20 amp branch circuit returns tapped onto one conductor. Both of these conductors are carrying return current. How much current is being carried on the conductor from the splice to the return bus?

Depends if the neutrals are on the same phase or not.

Same phase would be additive. The sum of the current values.

Opposite phase would be the difference between the two returning current values.