Grounds and neutrals sharing terminals

[mathew stouffer]

Other than the fact this panel looks like a bowl of pasta, is there any configuration which allow grounds and neutrals to share the same terminals. The house was built in 81 and it is a Square D panel.

Thanks

[Gunnar Alquist]

Matt,

Lots of information regarding ground/neutral on this board. do a search for more info.

In brief, ground & neutral must be bonded/connected together in the service equipment panel and must be isolated in other (dowstream) panels. Since this does not have a service disconnect breaker, I would assume that it is not the service equipment and the grounds/neutrals should be isolated. If it is the service equipment panel, then it should have a disconnect breaker, and I don't see one. As a result, it is wrong either way.

Interesting that the house is '81. It looks like there are AFCI breakers and they have not been around that long. That means that someone (electrical contractor?) has been in this panel and added the AFCI breakers but did not address the ground/neutral.

[John Arnold]

Other than the fact this panel looks like a bowl of pasta, is there any configuration which allow grounds and neutrals to share the same terminals. The house was built in 81 and it is a Square D panel.

Thanks

If you literally mean the same "terminal", then maybe you're not asking about ground/neutral bonding?
The neutrals should be one per terminal. No more than one neutral, and no other conductors, including grounding conductors, sharing that terminal.

[Jerry Peck]

Gunnar and John are both correct.

I see both conditions and neither condition is allowed at panels which are not service equipment, and, what John is describing is not allowed even in panels which are part of the service equipment.

[Ted Menelly]

I know it may be overkill but when I see pasta thrown in a panel I will write it up to be evaluated by a licensed competent electrician and not the one that did it.

I don't think you have to worry about the one that did it because no competent electrician would have made the interior of a panel look like that. Hence, the write up. Someone put a panel in or moved the panel and it was not a competent electrician. I see these panels from the earlier 80's and earlier all the time that are the main panel and no disconnect. I write that up as well.

Depending on the panel you can put more than one neutral in the same whole (depending on the panel)

Ground and neutrals on the same bar is not allowed.

[Jerry Peck]

Depending on the panel you can put more than one neutral in the same whole (depending on the panel)

Nope. Never.

Not "more than one neutral".

Depending on the panel, you can put more than one ground in the same terminal.

[Ted Menelly]

Nope. Never.

Not "more than one neutral".

Depending on the panel, you can put more than one ground in the same terminal.


OOOOPs, Sorry. Ground, depending on the panel.

Although I do believe I read a post in the past where a particular panel manufacture did say it was alright.

[Jerry Peck]

Although I do believe I read a post in the past where a particular panel manufacture did say it was alright.


It's not that they used to say it was alright, they simply did not used to say 'not to do it'.

The NEC left it up to the manufacturer and UL, and, the UL standard to which they were tested, listed, and labeled, never said it was okay. Thus 110.3(B) always said 'it is not okay, because the manufacturer does not say it it okay, and because it has to be installed and used in accordance with its listing, which said not to do it.

Eventually, the NEC simply picked it up and came right to the point, saying 'it is not okay' 'period'.

[Ted Menelly]

It's not that they used to say it was alright, they simply did not used to say 'not to do it'.

The NEC left it up to the manufacturer and UL, and, the UL standard to which they were tested, listed, and labeled, never said it was okay. Thus 110.3(B) always said 'it is not okay, because the manufacturer does not say it it okay, and because it has to be installed and used in accordance with its listing, which said not to do it.

Eventually, the NEC simply picked it up and came right to the point, saying 'it is not okay' 'period'.
Thanks Jerry

[Rollie Meyers]

Some makes allow up to 3 ECG's per terminal ( this is where reading the label is important) BUT.... if allowed must be the same size, & material, no mixing 12 &14 AWG other sizes or copper and aluminum conductors.

[James Duffin]

JP is correct....

[Paul Johnston]

If the meter is attached to the house and has a disconnect then a main breaker is not required in the distribution box.

[Ken Amelin]

Paul brought up a good point about the main breaker at the meter, which also brought up more questions.

If the main breaker is outside at the meter, is that main breaker box considered the the main service panel?

And would the distribution panel after the main breaker require isolated grounds and neutrals?

What is the definition of the main service panel?

[Jerry Peck]

If the meter is attached to the house and has a disconnect then a main breaker is not required in the distribution box.

Not required, but, in my opinion, it is 'safer' to install a 'main for the panel' at each panel. Not much extra cost either, but, yes, there is an 'extra cost' and, 'it is is not required' - just a personal preference. Having a 'main for the panel' does not affect the location of the neural being bonded to ground nor where the neutral is isolated from ground.


Paul brought up a good point about the main breaker at the meter, which also brought up more questions.

If the main breaker is outside at the meter, is that main breaker box considered the the main service panel?

No. That is "service equipment".

However, *if* there is a main breaker outside at the meter, and there is a panel 'in that same enclosure', then the main disconnect and that panel become "the service equipment" and that panel could be called the "service panel". However "service panel" does not designate the same thing as "service equipment", as "service panel" would only be the "panel section" whereas "service equipment" would include the main disconnect, that panel and anything else in that same enclosure with the main disconnect.

Think of it this way: If there is a main disconnect outside, with a panel directly adjacent to it, the main disconnect enclosure is the "service equipment" and that panel directly adjacent to it is simply just a "panel", it is no longer the "service panel".

The difference being that one panel is "in the same enclosure as" "the service equipment" and the other panel is not.


And would the distribution panel after the main breaker require isolated grounds and neutrals?

Splitting hairs here, but (as described above) if the panel is "in the same enclosure or not" makes the difference.

If you are asking about any panel downstream (outside the service equipment enclosure), then, yes, the neutral needs to be isolated from ground.


What is the definition of the main service panel?

Hopefully I've described that above.

If the panel "is in the same enclosure as" the service equipment (the main disconnect), you could call it the "service panel". In reality it is 'just a panel' and is wired not different than any other panel. The neutral is still bonded to ground "at the service equipment" - which just happens to be in that same enclosure with that panel.

Hopefully I did not add any confusion with that last paragraph.

[Ken Amelin]

Hi Jerry,

Thanks for the clarification.
It's still not perfectly clear to me though. (I'm not always the sharpest knife in the drawer).

If the main breaker is outside under the meter box and the distribution panel (without an additional main breaker) is located within three feet (connected by a cable) would a separate ground and separate isolated netrual bar be required at this distribution panel?

Also, same question but this time are separate ground and isolated neutrals required if the same distribution panel has a second main breaker disconnect?

Thanks

[Jerry Peck]

If the main breaker is outside under the meter box and the distribution panel (without an additional main breaker) is located within three feet (connected by a cable) would a separate ground and separate isolated netrual bar be required at this distribution panel?

Ken,

Even if that distribution panel was located immediately adjacent to, and connected to, the service equipment by a closed chase nipple, leaving 'just enough room to open and close the covers of the two enclosures' - yes, the neutral would be required to be isolated from ground in that distribution panel ... whether or not it had its own main breaker which was not the service equipment main - that would not matter.


Also, same question but this time are separate ground and isolated neutrals required if the same distribution panel has a second main breaker disconnect?

See above.

Whether or not ... a panel has its own main breaker (which is not "the" service disconnect main") - the neutral is would be isolated from ground.

I clarified that so no one would think - 'But, but, if the panel has its own main breaker "and" that main breaker is the "service disconnect main" ... are you telling me that the neutral should be isolated from ground?

That is why I always say to think of it this way: 'Is it "service equipment"?' If 'Yes.', then the neutral is bonded to ground, if 'No.', then the neutral is isolated from ground.

The key is "Is it "service equipment"?"

"Service equipment" is the enclosure where the main service disconnect is located.

It may, or may not, be near the meter.

It may, or may not, have a panelboard in the enclosure with it.

In fact, you could have a combination meter/disconnect/panel with a separation wall between the meter section and the disconnect/panel section (that separation wall is required in combination enclosures).

Hopefully I did not include too much extra information and add further confusion. ;)

[Ken Amelin]

Jerry,

It is now perfectly clear!

The key for me is the definition - ""Service equipment" is the enclosure where the main service disconnect is located."

Many Thanks

[Clay White]

Equipment grounds should not share the same terminal on the bus bar, correct?

[Jerry Peck]

Equipment grounds should not share the same terminal on the bus bar, correct?


Correct.

Additionally, 2 neutrals should not share the same terminal.

In fact, 1 neutral should be in a terminal by itself, with nothing else in that terminal.

[Jerry Peck]

The key for me is the definition - ""Service equipment" is the enclosure where the main service disconnect is located."

Ken,

Additionally, the main service overcurrent device is required to located either in that same enclosure or immediately adjacent thereto.

Which mean you *could* have a main disconnect in one enclosure, and the overcurrent protection in a second enclosure chase nippled right next to it.