# Sub Panel Grounding Options??



## MTN REMODEL LLC (Sep 3, 2010)

Friends....

I'm back at my kids old home in SoCal and am curious/concerned with something as a GC that I've not run into.

They have a subpanel (located virtually next to the main, actually two stud bays over). The main is interior and flush mounted, the sub is surface mounted with it's feed from behind and presently not visible.)
(The neutral of the sub has not been floated, which I fully understand needs correction and is not my question.)

Because I've yet not torn into the wall, I'm uncertain the subpanel has even been grounded. One there is no ground wire pulled...but I am uncertain if the feed to the subpanel is in a conduit, and if it is in a metal clad or ridgid, is that code compliant for a 100 amp feed to the subpanel. ??



As of now, I'm uncertain if the sub is grounded, because continuity wise, the neutral is not floated and consequently I'm "incorrectly grounded" thru the neutral. I would/will float it to check for any conduit ground, except it's a rats nest in there and will take significant work to untangle. If I find a conduit ground from sub to main that is legit, fine and I'll go ahead and float it. If that conduit ground is not legit, I want to at that time tear apart my walls (not so easy because of stucco issues and tile) and run a #8 separte ground wire. 

If it was bx, I know that that is not a legit ground anymore (am I grandfathered though and it is a short run). But will MC or ridgid suffice for any size ground wire... in this case for #8 ground for 100 amp sub panel service.

Thanks for any advice...

Peter


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## aptpupil (Jun 12, 2010)

Can't run a ground wire through the existing conduit? Seems like a short run so it would be worth a shot before tearing up the walls.


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## MTN REMODEL LLC (Sep 3, 2010)

Thanks apt...

I agree and that would be probably my first try... don't know as yet as both panels are a rats nest... but I'm still interested if I find ridgid or mc... is that a legit (code compliant) sub panel ground.

Actually, I've only encountered sub panels with a separate ground pulled or a sheathed ground cable. As far as employing conduit as ground, I only know it used in branch circuits.

Thanks

Peter


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## aptpupil (Jun 12, 2010)

I've never done it, but I believe that you can use solid conduit as an EGC. That said, don't listen to me...wait for 480 to come along and give you the real answer.


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## CScalf (Dec 18, 2008)

grounding is for sparky's, you are a GC, so therefore you don't need it:whistling


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## tjbnwi (Feb 24, 2009)

EMT and it's fittings are an approved ground.

From the UL White Book

Electrical Metallic Tubing Fittings (FKAV)
Grounding — These fittings are considered suitable for grounding for
use in circuits over and under 250 V and where installed in accordance
with ANSI/NFPA 70, ‘‘National Electrical Code.’’

If they are UL listed, they are approved for grounding.

Tom


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## iggy (Mar 3, 2013)

not familiar with 'floating" but I think you are talking about "bonding" the neutral or not" bonding". You do not bond the neutral in a sub panel it requires a seperate grounding path. The simplest to explain would be run a seperate grounding conductor ran with the other conductors. If you want to use the conduit alone you can but you must comply with certain rules.


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## MTN REMODEL LLC (Sep 3, 2010)

Cscalf... Great:clap:

By the way, guess you don't need AC or electricity.. see below. 

Best Regards....Peter



-------------------------------------------------------------------------------Just a past post from Cscalfs:,(I don't know how to quote accross threads... Peter)

Ok, so I couldn't get my ac to turn on the other night so I said no biggie, called my buddy that does that stuff, he said he would come look at it, hasn't showed up yet, (2 days now) 

so I go out and look at it, it is supposed to have the piece of plastic with the two strips of copper on it plugged in, and it isn't. (not even there)
So I decided well, until I can go get one of those in the morning, I would just wire the wires together accordingly no biggie.

I do this, and it still doesn't work, so obviously there is a condenser problem, now here is my question for you sparky's, why would some power in my house not be working now? 

I killed power to the hole house, (because the wiring is well lets say labled incorrectly) to do what I was doing on the outside box for the ac.

well now my basement doesn't have any power, nor my bedroom living room or dining room, none of the outlets work in those rooms, couple of the ceiling lights work, so what could be wrong, I hooked everything back up correctly to the terminals, as I took a pic of it before so I would know how to put it back when I got the piece I needed. 


Anyone got any ideas? 

__________________
"Your problem does not constitute an emergency on my part"

I do it for the love of God, Country, The Corps, Apple Pie, & Poontang! 









Warning: The topics covered on this site include activities


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## MTN REMODEL LLC (Sep 3, 2010)

tjbnwi said:


> EMT and it's fittings are an approved ground.
> 
> From the UL White Book
> 
> ...


Tj... Thanks ... and I guess ridgid (as well as emt) is legit also if that's what I find. I think I'm correct that old BX would not be legit. 

I guess I was not certain/understood if conduits to a sub panel had any amperage constraints on them... but apparently only volts.

Thank ya sir....Peter


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## MTN REMODEL LLC (Sep 3, 2010)

iggy said:


> not familiar with 'floating" but I think you are talking about "bonding" the neutral or not" bonding". You do not bond the neutral in a sub panel it requires a seperate grounding path. The simplest to explain would be run a seperate grounding conductor ran with the other conductors. If you want to use the conduit alone you can but you must comply with certain rules.


Iggy... Thanks... You understand entirely... I guess in Colorado (I'm out of state in Ca helping my kid) we just use the term "floating" the neutral for unbonding the neutral in a sub panel and "float" the neutral back to the main with no bonding at the sub. 

I just wasn't sure of requirements/constraints using the conduit as the EGC when employing it for 100 amp sub panel service.

Thank Ya... Peter


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## iggy (Mar 3, 2013)

you can use the conduit but you need to make sure it is solidly connected from panel to panel with proper fittings. If it is connected thru a concentric knock out to either panel you will need a bonding bushing and a grounding jumper .


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## MTN REMODEL LLC (Sep 3, 2010)

MTN REMODEL LLC said:


> Cscalf... Great:clap:
> 
> By the way, guess you don't need AC or electricity.. see below.
> 
> ...


By the way Cscalf... I'm kinda of a newbie to the computer, but just an old f___ to construction.

In response to your previous post asking why you don't have electricity.... did you pay your electric bill?????? :clap:

If I misunderstood your response to my inquiry, honestly my apology.

Peter


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## CScalf (Dec 18, 2008)

You did I was teasing...that post you quoted of mine is really really really old...I dont even remember why it was off lol


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## MTN REMODEL LLC (Sep 3, 2010)

iggy said:


> you can use the conduit but you need to make sure it is solidly connected from panel to panel with proper fittings. If it is connected thru a concentric knock out to either panel you will need a bonding bushing and a grounding jumper .


Iggy... Thank ya again!!!! 

I was fully aware of the concentric bushing requirement... BUT I was not aware of the jumper. I suppose I can find that bushing with a jumper lug on it , and go either directly to my box and/or my ground bar??

My feed is coming in through a concentric with a bushing but no jumper (from best I can currently see through my rat's nest.)

Best Regards.... Peter


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## MTN REMODEL LLC (Sep 3, 2010)

CScalf said:


> You did I was teasing...that post you quoted of mine is really really really old...I dont even remember why it was off lol


Cscalf.... My apolgies Bubbi... as I said I'm new to this.

BUT, if we can get this exception you suggested codified (that as GC's we don't need the NEC), put me on the list to contribute.

Best... Peter ... by the way, I really like your sign off (don't know what you call it.)


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## rselectric1 (Sep 20, 2009)

MTN REMODEL LLC said:


> Thanks apt...
> 
> I agree and that would be probably my first try... don't know as yet as both panels are a rats nest... but I'm still interested if I find ridgid or mc... is that a legit (code compliant) sub panel ground.
> 
> ...


If the sub-panel is fed through properly installed EMT, that is the ground. Make sure that the neutral/ground buss is not bonded to the panel box (at the sub) and all should be well.


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## MTN REMODEL LLC (Sep 3, 2010)

rselectric1 said:


> If the sub-panel is fed through properly installed EMT, that is the ground. Make sure that the neutral/ground buss is not bonded to the panel box (at the sub) and all should be well.


RS... I'm sure we're on the same page... but I do want the ground bus jumped/connected to the panel box.... I just want the neutral floating.... ie, not bonded.


Best Peter


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## MTN REMODEL LLC (Sep 3, 2010)

480...

Where are you???... still trying to catch that bast___ that's at your home when you're away.:clap:

Just and old F's joke... if I'm outa line... I apologize... I'm a newbie to Mr Computer


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## rselectric1 (Sep 20, 2009)

MTN REMODEL LLC said:


> RS... I'm sure we're on the same page... but I do want the ground bus jumped/connected to the panel box.... I just want the neutral floating.... ie, not bonded.
> 
> 
> Best Peter


Let's let 480 figure this out. He's MY electrician.:laughing:

The neutral (from the POCO) and the grounding method must me bonded at the main panel. At the sub-panel, there must be continuity between the neutrals, and continuity between the grounds, but they must not be connected TOGETHER *at* the sub-panel.

I have not dealt with this "floating neutral" thing you mention at the main panel.

Paging 480 Sparky! Edumicate us on this one!:clap:


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## MTN REMODEL LLC (Sep 3, 2010)

rselectric1 said:


> Let's let 480 figure this out. He's MY electrician.:laughing:
> 
> The neutral (from the POCO) and the grounding method must me bonded at the main panel. At the sub-panel, there must be continuity between the neutrals, and continuity between the grounds, but they must not be connected TOGETHER *at* the sub-panel.
> 
> ...


RS... I'm sure we're on the same page. First of all, my references are to the sub panel... not the main. You and I agree that we need continuity between the neutrals and continuity between the grounds... and not continuity between the two as far as the subpanel is concerned. (We technically would have continuity with a multi-meter in so far as they are bonded upstream at the main).

My only comment was that I want the ground bar/buss bonded/jumped/connected to the subpanel box, such that I have itr grounded back to the main. 

I'm sure we're saying the same thing... "floating" the neutral is just our local term for unbonding the neutral from the panel box/and/ground bar in a subpanel... as it often comes out of the box with a jumper between the ground/neutral bars/busses.

Best to ya.... Peter


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