techmavin
Member
- Location
- New Jersey
Is is OK as per NEC to mix the Neutral and Ground in the main panel?
What are the risks of doing that?
What are the risks of doing that?
Mixing Neutral and Ground in the main panel
- Thread starter techmavin
- Start date
- Status
Or are you asking about terminating both the grounding and grounded conductors under the same terminal? This is verboten.
If you referring to terminating them on the same bus bar (but separate terminals), that depends on whether the panel contains 'the first point of disconnect'.
If you referring to terminating them on the same bus bar (but separate terminals), that depends on whether the panel contains 'the first point of disconnect'.
- Location
- New Jersey
- Occupation
- Journeyman Electrician
Are you asking about them (neutrals and EGC's) terminating on the same bus bar? What do you mean by main panel is this a service?
Welcome to the Forum.
Assuming this is a Service panel where neutral (grounded white) and grounding (bare or green) are all on the same bar, I see the following issues:
Only one grounded wire per terminal is allowed in most cases in a panelboard (do not put the white and bare in the same hole).
I think is looks cleaner when the white and bare follow the same path and land on adjacent screws.
A risk I see, especially with the 2020 NEC wanting an outside disconnect, is the main panel could one day become a subpanel. Now the grounded and grounding wires need to be on different bars (neutral bar insulated, grounding bar bonded to cabinet). That could be ugly depending on the lengths of wire you have in the panel and if you only have a neutral bar on one side whereas before you had them on both sides.
Only one grounded wire per terminal is allowed in most cases in a panelboard (do not put the white and bare in the same hole).
I think is looks cleaner when the white and bare follow the same path and land on adjacent screws.
A risk I see, especially with the 2020 NEC wanting an outside disconnect, is the main panel could one day become a subpanel. Now the grounded and grounding wires need to be on different bars (neutral bar insulated, grounding bar bonded to cabinet). That could be ugly depending on the lengths of wire you have in the panel and if you only have a neutral bar on one side whereas before you had them on both sides.
- Location
- Bremerton, Washington
- Occupation
- Master Electrician
Its very helpful if we all could use the correct code terms for grounding and bonding. If you look up the article 100 definition of ground you will see what I mean. I am sure in 1 or 2 code cycles we will see all the incorrect NEC use of ground replaced (a lot of that done in the 2020 NEC) and perhaps change EGC to EBC!
Or as Mike Holt once said
"What color is it and what does it do"?
kwired
Electron manager
- Location
- NE Nebraska
2020 is only requiring an emergency disconnect outside and not requiring it to be the "service disconnect".
I think they left a lot of things up to user interpretation with this though. And AHJ nearly always wins in any interpretation battles.
If you put a disconnect outside that can also qualify as a service disconnecting means, chances are it will be considered the service disconnecting means, but if you put an unfused switch outside then it can only be used as an emergency disconnecting means.
ggunn
PE (Electrical), NABCEP certified
- Location
- Austin, TX, USA
- Occupation
- Consulting Electrical Engineer - Photovoltaic Systems
So of course, if N and G are bonded at the disco then you must keep them separated in the panel that follows it. We occasionally have to add a main service disco ahead of a panel where N and G are mixed on the terminal bar(s) in the MDP, and our guys have to pull them all out and separate them.
kwired
Electron manager
- Location
- NE Nebraska
If said disconnect is not the "service disconnecting means" then you still technically have service conductors after the disconnect. You separate N and G after the service disconnect, you bond all metallic enclosures to the grounded conductor before and including the service disconnecting means.
I think the intent though it isn't crystal clear is that you can have a non fused disconnect serving this emergency disconnect purpose, it is not the service disconnect and must be labeled accordingly. Need to go back and read what it says, but seem to recall some specific labeling requirements.
ggunn
PE (Electrical), NABCEP certified
- Location
- Austin, TX, USA
- Occupation
- Consulting Electrical Engineer - Photovoltaic Systems
The ATSs we usually install ahead of the MDP have OCPD and a N-G bond so we have to separate N and G in the MDP. Sometimes it's painful.
- Location
- Bremerton, Washington
- Occupation
- Master Electrician
Good point. I would look for a manufacturer to release a meter/disconnect combo device, all labeled as emergency disconnect.
hbiss
EC, Westchester, New York NEC: 2014
- Location
- Hawthorne, New York NEC: 2014
- Occupation
- EC
I would think that would make everybody happy (except if there is a generator ATS). No extra work required. I also think that this requirement be put on hold until such meter pans become available.
-Hal
romex jockey
Senior Member
- Location
- Vermont
- Occupation
- electrician
kwired
Electron manager
- Location
- NE Nebraska
Nothing wrong with meter/disconnects that are already out there, just need proper labels, and such labels probably need field applied as there can be differences in usage at times.
techmavin
Member
- Location
- New Jersey
Also, if one had to add solar panels then the main panel can become a subpanel. So, best to keep them on separate busbars.
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
Another reason to land neutrals on the neutral bus and EGCs on the EGC bus is to preserve neutral-bus terminals.
EGCs can use the enclosure and MBJ, but neutrals must use the neutral bus.
EGCs can use the enclosure and MBJ, but neutrals must use the neutral bus.
kwired
Electron manager
- Location
- NE Nebraska
I've mostly only run into issues mentioned in dwellings, as well as cases where a lot of MC cable is run (where you have one EGC for pretty much every breaker pole used) but now we have all those required AFCI's, and if you use plug on neutral breakers is not so much a problem.
techmavin
Member
- Location
- New Jersey
Yes same bus bar.Are you asking about them (neutrals and EGC's) terminating on the same bus bar? What do you mean by main panel is this a service?
Welcome to the Forum.
As long as the Grounded conductors are not sharing a single terminal with another Grounded conductor or EGC it is fine and normal. Do you have an EC on board to help you.
Roger
kwired
Electron manager
- Location
- NE Nebraska
Can also land EGC's on the grounded bus at first disconnecting means of separately derived system, if the system bond is performed at that location, if bond is at the source then you must keep them separate starting at the source.
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