no ground rod needed for detached garage ?

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Stevenfyeager

Senior Member
Location
United States, Indiana
Occupation
electrical contractor
I was planning on driving a ground rod when replacing overhead service to a detached garage. I was talking to the elec inspector at the jobsite. He said, "no, you don't need to because you are replacing the overhead existing triplex with quadplex 4 wire. You'll have 4 wires." I was surprised and asked him about that. The service panel will be a 4 breaker main lug subpanel.
 

Hv&Lv

Senior Member
Location
-
Occupation
Engineer/Technician
I was planning on driving a ground rod when replacing overhead service to a detached garage. I was talking to the elec inspector at the jobsite. He said, "no, you don't need to because you are replacing the overhead existing triplex with quadplex 4 wire. You'll have 4 wires." I was surprised and asked him about that. The service panel will be a 4 breaker main lug subpanel.

Would you drive a ground rod with a four wire feeder from the house panel?
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
A detached structure with its own panel requires a GES, using two rods to make one is usually the easiest option.
 
I was planning on driving a ground rod when replacing overhead service to a detached garage. I was talking to the elec inspector at the jobsite. He said, "no, you don't need to because you are replacing the overhead existing triplex with quadplex 4 wire. You'll have 4 wires." I was surprised and asked him about that. The service panel will be a 4 breaker main lug subpanel.
I think this is a feeder even though you used the word "service" several times, correct?

Yes you need the rods, unless you are running a branch circuit.
 

tom baker

First Chief Moderator & NEC Expert
Staff member
Location
Bremerton, Washington
Occupation
Master Electrician
Inspector is wrong, but i have made same mistake on 4 wire feeder to separate building.
green wire in feeder is for bonding, get electrons back to source to clear a line to case fault. Ground rods are for lightning. If you have a 40 amp or 4000 amp feeder you need a GES.
 

hbiss

EC, Westchester, New York NEC: 2014
Location
Hawthorne, New York NEC: 2014
Occupation
EC
Easy way to remember:

If you run branch circuits out to the building from breakers in the main panel to receptacles and lighting in the out building, no ground rods required.

If you install a sub panel in the outbuilding to provide the branch circuits and feed it from the main panel then you need to drive two ground rods.

In both cases you would run the full compliment of hot(s), neutral and ground from the main panel to the out building.

-Hal
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
He said, "no, you don't need to because you are replacing the overhead existing triplex with quadplex 4 wire. You'll have 4 wires." I was surprised and asked him about that.

Especially scary that he obviously considers rods as acceptable substitutes for EGCs in the first place. :eek:
 

hbiss

EC, Westchester, New York NEC: 2014
Location
Hawthorne, New York NEC: 2014
Occupation
EC
I'm not going to go and look, but I don't recall where it says that if I run two separate branch circuits, fed from separate breakers back in the main panel, both with their own hot and neutral and a common ground that I need to drive ground rods.

I've done just that on several occasions, one I remember that had one circuit for the receptacles and lighting within the outbuilding and the other on a site lighting circuit for the lighting around the outside of the building that came on with all the other outdoor lighting around the property. The two circuits weren't even from the same panels.

-Hal
 
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MAC702

Senior Member
Location
Clark County, NV
I'm not going to go and look, but I don't recall where it says that if I run two separate branch circuits, both with their own hot and neutral and a common ground I need to drive ground rods.

I thought you were not permitted to run two separate branch circuits to an outbuilding. You'd be required to run a feeder and use a panel. Maybe I'm missing something?
 

hbiss

EC, Westchester, New York NEC: 2014
Location
Hawthorne, New York NEC: 2014
Occupation
EC
225.30(D)

(D) Different Characteristics. Additional feeders or branch circuits shall be permitted for different voltages, frequencies, or phases or for different uses, such as control of outside lighting from multiple locations.


Apparently this is what I remember.

-Hal
 

oldsparky52

Senior Member
I was planning on driving a ground rod when replacing overhead service to a detached garage. I was talking to the elec inspector at the jobsite. He said, "no, you don't need to because you are replacing the overhead existing triplex with quadplex 4 wire. You'll have 4 wires." I was surprised and asked him about that. The service panel will be a 4 breaker main lug subpanel.

I'm not going to look up the code articles, but IIRC, no only do you need the ground rods, you need a main disconnect. An MLO panel doesn't cut it (IIRC).
 

Srv52761

Senior Member
Location
lowa
Occupation
Energy Manager
The ' 6 switch rule', or "6 throw rule" allows no main disconnect needed if no more than 6 breakers, right ?

I am under the assumption this will no longer be the case for a detached building in the 2020 edition, and the disconnect will need to be on the exterior. Not sure where I heard or read this, but it is engrained in my aging brain for some reason... would appreciate a yay or nay to help me decide if my memory is as bad as my eye sight.
 

kwired

Electron manager
Location
NE Nebraska
The ' 6 switch rule', or "6 throw rule" allows no main disconnect needed if no more than 6 breakers, right ?

yes, but pay attention to details on the panel you are using, if feeder supplied you are likely still be fine but many are marked with something to the effect they are only suitable for use as service equipment when a main breaker is installed.
 
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