ground rod requirement on outbuildings.

[stew]

I thought there was an exception to ground rod requirements on detached structures served with one 15 or 20 a gfci protected circuit. Cant seem to locate it. Are they required in all instances or does an exception in this case change that?

 

[CONDUIT]

Take a look at 250.32a exception. Maybe that is what you are talking about.

 

[Dennis Alwon]

I have seen inspectors enforce a ground rod when a single circuit feeds a detached structure. They are incorrect as the exception clearly allows no ground rods.

 

[infinity]

For a single circuit or a MWBC a grounding electrode system is not required. I've heard of inspectors (incorrectly) asking for a CEE connection on outbuildings fed with only one circuit. :slaphead:

 

[GoldDigger]

For a single circuit or a MWBC a grounding electrode system is not required. I've heard of inspectors (incorrectly) asking for a CEE connection on outbuildings fed with only one circuit. :slaphead:

However, as discussed in other threads, if a CEE exists at the garage, it must be connected to the overall GES anyway, IMHO.
You are not required to create a ground by driving a rod electrode which was not there before. But if an electrode exists, it is hard to avoid using it.
The distinction made in the other thread was that if the required length of rebar was part of a complying mass of concrete, a CEE exists and must be used even if no provision was ever made during the pour to connect to it.
However, if there is already a CEE at the main building, there is then no requirement to connect more than one CEE to the GES. It is not 100% clear to me that this applies when the two CEEs are part of different structures though.

 

[infinity]

However, as discussed in other threads, if a CEE exists at the garage, it must be connected to the overall GES anyway, IMHO.
You are not required to create a ground by driving a rod electrode which was not there before. But if an electrode exists, it is hard to avoid using it.
The distinction made in the other thread was that if the required length of rebar was part of a complying mass of concrete, a CEE exists and must be used even if no provision was ever made during the pour to connect to it.
However, if there is already a CEE at the main building, there is then no requirement to connect more than one CEE to the GES. It is not 100% clear to me that this applies when the two CEEs are part of different structures though.

Interesting point but I'm not so sure, the exception clearly states that a grounding electrode, made or otherwise is not required.

250.32 Buildings or Structures Supplied by a Feeder(s)
or Branch Circuit(s).
(A) Grounding Electrode. Building(s) or structure(s) sup-
plied by feeder(s) or branch circuit(s) shall have a ground-
ing 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 ground-
ing 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.

 

[Gregg Harris]

Interesting point but I'm not so sure, the exception clearly states that a grounding electrode, made or otherwise is not required.

I would agree also. Single or individual multiwire branch circuit with grounding conductor does not require a grounding electrode at the separate building.

 

[GoldDigger]

Interesting point but I'm not so sure, the exception clearly states that a grounding electrode, made or otherwise is not required.

I read this as saying that for a single circuit no ground electrode needs to be made, not that an existing one need not be connected. But the language could be clearer.
Especially since the requirement to connect all existing electrodes (except additional CEEs) is in a different section.

 

[infinity]

I read this as saying that for a single circuit no ground electrode needs to be made, not that an existing one need not be connected. But the language could be clearer.
Especially since the requirement to connect all existing electrodes (except additional CEEs) is in a different section.

I agree that the wording is somewhat unclear. If I had to argue intent I would go with the exception which is clear that no GES is required.

 

[Dennis Alwon]

I agree that the wording is somewhat unclear. If I had to argue intent I would go with the exception which is clear that no GES is required.

I am with you on that.

 

[GoldDigger]

I agree that the wording is somewhat unclear. If I had to argue intent I would go with the exception which is clear that no GES is required.

And there is exactly where we differ. There is a difference between whether an electrode is required (never more than two ground rods required in most cases, except for local amendments), and what you are required to do with an electrode when it already exists.
Do you agree that if someone like a cable installer were to drive a third rod electrode in the vicinity of the others near the main house that someone(?) would be required to connect it, even though nobody was required to create it in the first place?

And since you are still required to carry an EGC, it may not be too burdensome to connect the existing electrode to the panel or jbox where the single circuit enters? (There may be an issue with the size of the EGC, of course, since it would now be part of the GES as well as being a branch circuit EGC. I had not thought of that initially.)

 

[iwire]

I read this as saying that for a single circuit no ground electrode needs to be made, not that an existing one need not be connected. But the language could be clearer.
Especially since the requirement to connect all existing electrodes (except additional CEEs) is in a different section.

I don't see any confusion, no GE required made or not.