Grounding Question.

[aptman3]

Today I was fixing some violation work at a single family dwelling. The detached garage has an old service (hot/neutral) with no ground. The garage has 1 switch for a light and 2 outlets. I was told by the inspector today that he wanted me to install a ground rod just outside the garage and connect a wire from the garage GFI's to the ground rod outside. I have never heard of this method and after taking Mike Holt's grounding and bonding classes I don't believe he would agree with this, unless I am misunderstanding. Installing a ground rod would not be enough to effectively clear a ground fault. The proper way would be to run a ground wire back to the source (Panel). I also thought that since this is existing work, the inspector should have let me install tamper-proof GFI's with "No equipment Ground" stickers on them. Let me know any thoughts as I'm trying to learn and understand this better. I am going to watch Mike's Grounding and Bonding DVD again. Thanks!

 

[ActionDave]

Today I was fixing some violation work at a single family dwelling. The detached garage has an old service (hot/neutral) with no ground. The garage has 1 switch for a light and 2 outlets.

I was told by the inspector today that he wanted me to install a ground rod just outside the garage and connect a wire from the garage GFI's to the ground rod outside.

I have never heard of this method and after taking Mike Holt's grounding and bonding classes I don't believe he would agree with this, unless I am misunderstanding. Installing a ground rod would not be enough to effectively clear a ground fault.

The proper way would be to run a ground wire back to the source (Panel). I also thought that since this is existing work, the inspector should have let me install tamper-proof GFI's with "No equipment Ground" stickers on them.

Let me know any thoughts as I'm trying to learn and understand this better. I am going to watch Mike's Grounding and Bonding DVD again. Thanks!

That's better.

The inspector is partially correct in that the garage should have a ground rod because it is a separate structure.

You are correct in that a ground rod has nothing to do with clearing a fault.

What kind of inspector are you dealing with; a full time electrical inspector or one of those all purpose types?

 

[aptman3]

He is full-time but he is also all purpose. I noticed that he inspects other trades as well as electrical.

 

[hurk27]

Is this really a service or a single branch circuit fed from the house panel?

if this is a single branch circuit then there is no requirement for a grounding electrode, and replacing non-grounded receptacles with GFCI's is the correct and code compliant way on existing circuits, see 406.3(D)(3)(c)

The ground rod would serve no purpose connected to the grounding terminal of the GFCI receptacle, other then it would trip the GFCI if a fault to the EGC in a appliance plugged into it was to happen, but so would a person touching a GFCI protected hot and Earth without the rod or a EGC. I GFCI does not need to reference Earth or does it need an EGC to function.

but what a ground rod won't do is open a breaker at the full circuit available current.

To have a fault current path in a pre 2008 225 building such as this garage, the grounding could have been bonded to the neutral at the disconnect to the building? 250.32(B)(2) 2005 and earlier.

But then would this be allowed for a single branch circuit? I don't see any thing in 250.32(B)(2) that says no buttttt????

 

[ActionDave]

He is full-time but he is also all purpose. I noticed that he inspects other trades as well as electrical.

I thought so.

Hurk brings up a good point. Is this a single circuit from the main house that feeds the garage?

 

[Dennis Alwon]

It sounds like a branch circuit going to the garage. Look at 250.32(A) exception

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.
Exception: A grounding electrode shall not be required where only a single branch circuit, including a multiwire branch circuit, supplies the building or structure and the branch circuit includes an equipment grounding conductor for grounding the normally non–current-carrying metal parts of equipment.

 

[Rewire]

Get your code references together then have a friendly sit down with the inspector.

 

[jaylectricity]

It sounds like a branch circuit going to the garage. Look at 250.32(A) exception

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.
Exception: A grounding electrode shall not be required where only a single branch circuit, including a multiwire branch circuit, supplies the building or structure and the branch circuit includes an equipment grounding conductor for grounding the normally non?current-carrying metal parts of equipment.

I bolded the part of the exception that causes it to be useless in this application.

 

[LarryFine]

The detached garage has an old service (hot/neutral) with no ground.

Next question: Is this two conductors (120v) or three (120/240v)?

 

[K8MHZ]

How are you supposed to bond the electrode for the garage to the electrodes at the house?

What are you supposed to connect the GEC to, the neutral?

The inspector needs to do some brushing up on the information that he needs to do his job.

 

[hurk27]

How are you supposed to bond the electrode for the garage to the electrodes at the house?
What are you supposed to connect the GEC to, the neutral?

The inspector needs to do some brushing up on the information that he needs to do his job.

There is no requirement to interconnect electrodes of two different systems, a grounding electrode system is only required for Each building or structure, there is no requirement to interconnect between buildings.

250.50 Grounding Electrode System.
If available on the premises at each building or structure served, each item in 250.52(A)(1) through (A)(6) shall be bonded together to form the grounding electrode system. Where none of these electrodes are available, one or more of the electrodes specified in 250.52(A)(4) through (A)(7) shall be installed and used.

 

[K8MHZ]

There is no requirement to interconnect electrodes of two different systems, a grounding electrode system is only required for Each building or structure, there is no requirement to interconnect between buildings.

Let me state my question(s) differently.

The electrodes are required to be bonded to the neutral at the first disco (the bull's eye). There is no allowance for bonding at any other point.

We have a two wire feed, one hot and one neutral to the garage. The bull's eye is at the home.

Any grounding device must be bonded to the neutral at the bull's eye only.

So, even though not directly required, if you follow the rest of the code there needs to be a conductor from the new electrode to the bull's eye, which indeed bonds it to the other electrodes.

So, if there is a wire connected on one end to a rod, where does the other end go? If it's not bonded to the neutral as required it's useless and illegal and it can't be bonded to the neutral of a two wire system anywhere but the bull's eye.

For the additional optional electrode to be legal and effective, there needs to be a grounding conductor along with the grounded and hot conductors coming into the building. Since no mention was made of replacing the two wire feed with a three wire feed I posed the questions. In trying to keep it simple I guess they lost their meanings.

 

[jxofaltrds]

Let me state my question(s) differently.

The electrodes are required to be bonded to the neutral at the first disco (the bull's eye). There is no allowance for bonding at any other point.

We have a two wire feed, one hot and one neutral to the garage. The bull's eye is at the home.

Any grounding device must be bonded to the neutral at the bull's eye only.

So, even though not directly required, if you follow the rest of the code there needs to be a conductor from the new electrode to the bull's eye, which indeed bonds it to the other electrodes.

So, if there is a wire connected on one end to a rod, where does the other end go? If it's not bonded to the neutral as required it's useless and illegal and it can't be bonded to the neutral of a two wire system anywhere but the bull's eye.

For the additional optional electrode to be legal and effective, there needs to be a grounding conductor along with the grounded and hot conductors coming into the building. Since no mention was made of replacing the two wire feed with a three wire feed I posed the questions. In trying to keep it simple I guess they lost their meanings.

I agree with both of Wayne's posts.

And why do you need an EGC at the garage?

 

[K8MHZ]

I agree with both of Wayne's posts.

And why do you need an EGC at the garage?

You don't. I never said that you did. But, you can have one if you wish. IF you do have one, there has to be a path from the electrode back to the bull's eye.

My question only applies if an additional electrode is placed. Without a separate grounding conductor back to the service there is no way for fault current to trip the OCPD legally. Technically, connecting the electrode to the neutral would provide a path to clear a fault, but that is not allowed by the NEC.

The inspector is wrong by requiring the electrode, we agree on that.

Do you not agree that if the electrode is placed that it has to be connected to a grounding conductor, which in this case does not exist?

If not, please explain what the electrode should be connected to.

 

[Dennis Alwon]

I agree with both of Wayne's posts.

And why do you need an EGC at the garage?

Do you mean GEC? You need the egc for a ground- a GEC is worthless without the EGC. Obviously in this situation there is no GEC required and if existing well-- you either upgrade or leave it. If you add to it I believe you need to run a new branch circuit out there, with a ground.

 

[LarryFine]

Any grounding device must be bonded to the neutral at the bull's eye only.

Within the same building, that is.

Pre-2008, in a detached building, you can re-ground the grounded conductor to electrodes, whether there is one or two line conductors.

 

[jxofaltrds]

Do you mean GEC? You need the egc for a ground- a GEC is worthless without the EGC. Obviously in this situation there is no GEC required and if existing well-- you either upgrade or leave it. If you add to it I believe you need to run a new branch circuit out there, with a ground.

Dennis

No. I did mean EGC.

"a GEC is worthless without the EGC."

I do not think that you said what you meant.

 

[Dennis Alwon]

Dennis

No. I did mean EGC.

"a GEC is worthless without the EGC."

I do not think that you said what you meant.

If the gec connects to a panel and is isolated from the neutral it will do nothing, however in the old code an egc was not req. from the house so the gec got connected to the grounded conductor. Of course, you know all this. To me a GEC on a 2 wire circuit is virtually worthless but I guess you could connect it to the grounded conductor. I would not bother with it.

 

[jxofaltrds]

If the gec connects to a panel and is isolated from the neutral it will do nothing, however in the old code an egc was not req. from the house so the gec got connected to the grounded conductor. Of course, you know all this. To me a GEC on a 2 wire circuit is virtually worthless but I guess you could connect it to the grounded conductor. I would not bother with it.

How is that any less effective on one 'leg' than when both 'legs' are present?

"If the gec connects to a panel and is isolated from the neutral it will do nothing,"

Agreed. But why would it be isolated? And why would this be done?

 

[Dennis Alwon]

Mike we are saying the same things. I personally think ground rods are worthless and perhaps has more value when there are more circuits involved. I just very little value in a ground rod- and perhaps 2 rods, for a single 2 wire circuit with or without ground. I never liked the neutral being hooked to the GEC even when it was legal. They changed it for a reason.