# Bonded Ground and Neutal in Outbuilding Panel



## VikingsFan (Apr 10, 2014)

I have a bit of a unique situation.  My outbuilding has two hots and a Neutral coming into it's panel, but a dedicated / separate grounding rod.  In this situation, should I bond the Neutral and Ground bus bars in the outbuilding sub panel?  See the attached image for a better understanding.


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## JoeD (Apr 10, 2014)

Yes you should. That setup was permitted in the past. New installations require a separate ground in the feeder.


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## Wuzzat? (Apr 10, 2014)

JoeD said:


> That setup was permitted in the past.


Meaning there was no jumper?



JoeD said:


> New installations require a separate ground in the feeder.


Meaning a cable with four conductors from main to outbuilding?


It's not my place to come up with a rationale for the electrical code, but:

Option 1, with outbuilding N & G unconnected, a person who is grounded at the outbuilding (let's say standing barefoot on wet ground) would see zero volts on outbuilding metal enclosures.

Option 2, with outbuilding N & G connected, a person who is grounded at the outbuilding would see 2-3 v on  outbuilding metal enclosures assuming current was being drawn by the outbuilding.

Option 3, with outbuilding N & G connected through a four wire cable from the main building and with outbuilding N & G unconnected, a person who is grounded at the outbuilding would see the voltage difference between the ground at the outbuilding and the ground at the main building.  
This voltage is probably indeterminate and small unless the current density in the ground happens to be very high, like in a metropolitan area.

I'd say go with option 1 but the electrical code people must have some good reason for picking option 3.

These various option voltages can be tested with a multimeter and a heavy 120v load turned on in the outbuilding.


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## VikingsFan (Apr 10, 2014)

Thanks for the replies!  I haven't encountered this situation before and wanted a second set of eyes.  I also am of the opinion that they bus bars should be separated, but that's just because it's been drilled into me that you always keep them separate in sub. panels.  If anyone else has other experience, or opinions, I would be glad to hear them!


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## Wuzzat? (Apr 10, 2014)

VikingsFan said:


> that you always keep them separate in sub. panels.


Which means you get a Single Point Ground.  It's necessary in some electronics gear but the ins and outs for resi wiring are not obvious.
http://www.google.com/search?client...TF-8#q=distributed+single+point+ground&rls=en


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## VikingsFan (Apr 10, 2014)

OK, so it seems like it's a Single Point Ground vs. Distributed Single Point Ground, but I'm not sure that's applicable.  It implies that I have an option of either using the common ground from the Service Panel, or tying the Service Panel Ground to the Neutral at multiple points with multiple earthing locations.  I have neither choice.  My choice is to either not tie the Neutral to a ground at all, or tie it into a separate ground altogether.  The challenge is that there is no continuous ground connection from the Service Panel to the outbuilding Sub-Panel, and running one would be a challenge. The last bit of confusion comes in that I would like to add a 30A GFCI / Arc Fault Detection breaker to the outbuilding, but I'm not certain that it would work considering the issues with the ground.


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## JoeD (Apr 11, 2014)

Under current code you do not have that option. Past codes allowed for a three feed to out buildings and a ground rod except under certain conditions. Current code requires a four wire feed to out buildings and a ground for all circumstances.


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## Wuzzat? (Apr 11, 2014)

VikingsFan said:


> I would like to add a 30A GFCI / Arc Fault Detection breaker to the outbuilding, but I'm not certain that it would work considering the issues with the ground.


And I don't know of any way you can find out ahead of time.  

You'd have to gamble the price of this device on the likelihood that you don't get nuisance tripping once per day/week/month/year, balanced with whatever marginal additional safety you'd get.  
GFCIs give you some safety but I can't get credible numbers on this and I have my doubts about AFCIs.  

BTW, GFCIs don't need a ground to work and maybe the same is true for AFCIs. 

Putting this in perspective, people dying from electricity each year is about 15x less than from driving a car.  Your odds are much better than this because you look before you leap.


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## nealtw (Apr 11, 2014)

I don't understand what the problem is?


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## speedy petey (Apr 12, 2014)

OK, if this is an existing installation it is FINE. The neutral IS bonded to the panel enclosure. It is treated just like a main panel. 

You have to remember, the ground rod and associated wire have NOTHING to do with the incoming feeder wire(s). A ground rod "ground" serves a completely different purpose.

Not sure why you would even want to, but you CANNOT use a GFI or AFCI feeder breaker in cases like this. You'll have to protect everything from the sub-panel location or local devices.


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## VikingsFan (Apr 12, 2014)

speedy petey said:


> . . . you CANNOT use a GFI or AFCI feeder breaker in cases like this. You'll have to protect everything from the sub-panel location or local devices.



Makes total sense.  I am looking to hook up a control panel for some power equipment that can be run wet.  I can easily add a DIN mount AFCI to that panel, however, which should suit my purposes fine. 

I'm still not clear on the whole ground / neutral bonded vs. not bonded, but the consensus seems to be that they should be connected in this scenario.  I would love to simply add a ground to the run from the main building to the outbuilding, but that would be a challenge.  There's no pull string and its a buried run of Sealtite that seems to make a few sharp turns. 

Anyway, I appreciate all the feedback.  I'm just trying to be safe here, and I'm glad there's a place I can get some solid advice. 

Thanks for all the great replies!


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## Wuzzat? (Apr 12, 2014)

VikingsFan said:


> I'm still not clear on the whole ground / neutral bonded vs. not bonded,


That makes two of us.

I will add that 

if 
you have a neutral conductor that is sensed by a GFCI and 
has a ground rod at each end, 

then
the soil will be pushing current through the neutral and
this may fool the GFCI because 
the current going out the hot lead is almost certain to be not the same as that returning on the neutral lead.  

Having just waded through the instructions for my income tax, you may notice that the electrical code is similar.  They are a bunch of IF-THEN-ELSE statements but are not quite so clearly stated.  

Also, there are logical fallacies in the elec. code, probably because the people who wrote it are likely not trained in symbolic logic.  Some percentage of electricians get tripped up on these fallacies.

If you haven't read
http://www.goodreads.com/book/show/6919310-how-math-can-save-your-life
on symbolic logic or done programming and you want to understand these opaque and arcane documents, I'll pray for you. 
The burden for understanding is on the reader and it might be an undue burden.  I'm sure this is true for the US Tax Code, and there is at least one CPA who agrees with me.


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## Bobby Cannon (Mar 28, 2021)

VikingsFan said:


> I have a bit of a unique situation.  My outbuilding has two hots and a Neutral coming into it's panel, but a dedicated / separate grounding rod.  In this situation, should I bond the Neutral and Ground bus bars in the outbuilding sub panel?  See the attached image for a better understanding.



How did this workout? Did you bond? I almost have this same setup however my "out bldg" doesn't even have a ground... I want to add a ground and do it correctly.


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## afjes_2016 (Mar 29, 2021)

.

Welcome to the forum Bobby. You will learn a lot here about electrical.

This post is 6 years old and the OP has not been online for 3 years.

.


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## Bobby Cannon (Mar 29, 2021)

Yeah I was just hoping. You never know. Maybe they'll get an email notice, log back in, and reply? It was worth a shot.


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## bud16415 (Mar 29, 2021)

Welcome Bobby   

Fell free to start a new thread and describe what your situation is and i'm sure some of the electrical pros will be along with the best advice. 

Sometime us non pros offer some advice also, but it is always better to get it from a pro.


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## Eddie_T (Mar 29, 2021)

Welcome aboard. I too sometimes wake up old threads if they have a useful history. It can save a lot of repetition. Grounding and bonding is a curious subject, sometimes defying logic.


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## Bobby Cannon (Mar 29, 2021)

I have taken pictures and will post a new thread. I will link it here when I have a chance to create it. I like the activity on this site. I just happen to run across it doing a bing image search.


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## Bobby Cannon (Mar 30, 2021)

ok, I added my question with a poll to this thread. (1) Disconnected Barn Sub Panel missing Ground? | HouseRepairTalk


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## ajaynejr (Apr 23, 2021)

The old feed would not have to be disconnected assuming it (without an equipment grounding conductor) was legal when it was installed. (It was much more than  6 years ago when ungrounded feeds were outlawed.)

Except if you need more amperage you would have to decommission the old feed when running a new fatter feed (with equipment grounding conductor) since only one feed is permitted between the two buildings.

While this feed and panel are in use grandfathered you may not have installed any metal interconnection, such as a switch loop or a water pipe or a TV coax cable or a recreational zip line, between the buildings.


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