# subpanel



## bluebird5 (Dec 13, 2010)

just wondering... if you have a subpanel in a seperate building like a shed or detached garage and you have 4 wires running to the main panel (ground, neutral, 2 hots), does the subpanel also need a ground rod? why or why not?


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## relectric (Feb 27, 2011)

You don't need a ground rod becase the panel is bonded back to the main by means of a wire. The only case may be if it feeds a building containing livestock, then a ground rod or plate may be required. If a seperate wire is ran be sure to remove the neutral bondng screw or strap.


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## 480sparky (Feb 1, 2009)

relectric said:


> You don't need a ground rod becase the panel is bonded back to the main by means of a wire. ...............



Saunter through 250.50 and you'll find otherwise.


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## aptpupil (Jun 12, 2010)

yes, you do.


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## woodchuck2 (Feb 27, 2008)

I always just run 3-wire and ground the panel, takes care of any arguments of grounding down the road.


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## 480sparky (Feb 1, 2009)

*250.32 Buildings or Structures Supplied by a Feeder(s) or Branch Circuit(s).
(A) Grounding Electrode. Building(s) or structure(s) supplied by feeder(s) or branch circuit(s) shall have a grounding electrode or grounding electrode system installed in accordance with Part III of Article 250. The grounding electrode conductor(s) shall be connected in accordance with 250.32(B) or (C). Where there is no existing grounding electrode, the grounding electrode(s) required in 250.50 shall be installed.*



'Nuff said.


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## muckusmc (Jul 19, 2008)

480sparky said:


> *250.32 Buildings or Structures Supplied by a Feeder(s) or Branch Circuit(s).
> (A) Grounding Electrode. Building(s) or structure(s) supplied by feeder(s) or branch circuit(s) shall have a grounding electrode or grounding electrode system installed in accordance with Part III of Article 250. The grounding electrode conductor(s) shall be connected in accordance with 250.32(B) or (C). Where there is no existing grounding electrode, the grounding electrode(s) required in 250.50 shall be installed.*
> 
> 
> ...


Depending on what code cycle is in play - prior to 2005?, 3 wire systems were acceptable.


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## 480sparky (Feb 1, 2009)

muckusmc said:


> Depending on what code cycle is in play - prior to 2005?, 3 wire systems were acceptable.



The language goes back to 1999.


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## bluebird5 (Dec 13, 2010)

sparky are you saying 4 wires and a ground rod? or is the ground from the panel concidered the grounding electrode?


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## 480sparky (Feb 1, 2009)

bluebird5 said:


> sparky are you saying 4 wires and a ground rod? or is the ground from the panel concidered the grounding electrode?



It says "shall have" and "if there's not one there already, put one in".


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## muckusmc (Jul 19, 2008)

480sparky said:


> The language goes back to 1999.


Your right - that's what I get for not looking it up. One of these days I'll learn.


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## griz (Nov 26, 2009)

480sparky said:


> The language goes back to 1999.





480sparky said:


> It says "shall have" and "if there's not one there already, put one in".





muckusmc said:


> Your right - that's what I get for not looking it up. One of these days I'll learn.


A great deal of room to argue tech stuff on here.
It's just that there ain't much arguing with 480.:notworthy


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## one man show (Dec 20, 2010)

*grounding seperate structure*

carefull sparkey 
the new 2010 code says that a four wire system is required 

(B) Grounded Systems.​​​​For a grounded system at the
separate building or structure,  *equipment grounding*
*conductor as described in 250.118 shall be run with the*
*supply conductors* and connected to the building or
structure disconnecting means and to the grounding
electrode(s). The equipment grounding conductor shall be
used for grounding or bonding of equipment, structures, or
frames required to be grounded or bonded. The equipment
grounding conductor shall be sized in accordance with
250.122. Any installed grounded conductor shall not be
connected to the equipment grounding conductor or to the​
grounding electrode( s).


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## one man show (Dec 20, 2010)

*grounding seperate structure*

do not put one in 
you cant have two seperate gounding systems

use the equipment grounding conductor with your supply conductors


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## one man show (Dec 20, 2010)

*seperate structure*

in the previous code it would depend on "is thier a metalic path back to the main srructure

is there a water pipe
metalic elec conduit
or even telephone wires
the equipment grounding conductor would be required

if not then a grounding electrode would be required


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## 480sparky (Feb 1, 2009)

one man show said:


> carefull sparkey
> the new 2010 code says that a four wire system is required
> 
> (B) Grounded Systems.​For a grounded system at the
> ...




The question isn't about running a EGC with the circuit. It's about whether a grounding electrode is required. Both are.


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## 480sparky (Feb 1, 2009)

one man show said:


> do not put one in
> you cant have two seperate gounding systems
> 
> use the equipment grounding conductor with your supply conductors



So running to a water pipe *and* a ground rod is illegal???


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## bhock (Feb 17, 2009)

480sparky said:


> So running to a water pipe *and* a ground rod is illegal???


Wouldn't that make it illegal to run ground to the rebar in a footer and also to an electrode illegal? Cause thats what code requires here...lol.


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## bhock (Feb 17, 2009)

And One Man...that paragraph you posted is also part of 2008 code, so it wasn't something that changed.


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## 480sparky (Feb 1, 2009)

one man show said:


> ............you cant have two seperate gounding systems...........


How about a Code reference?


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