Seperate Building

[tjmicsak]

I am about to install a feeder to a garage from a house service. I know I need rods at the garage, and am using 4-wire subfeed, and will isolate the neutral and ground at the garage. The issue is that both buildings have a common water line. What needs to be done different, or in addition because of this common path? I want to bond it if needed, or not bond it if it would pose a parellel path for current flow.

 

[Pierre C Belarge]

Think of it like this:

There are multiple houses on a street that share the same utility transformer. These same houses share a common water line through the street. Each house still uses the waterpipe as an electrode even though this pipe is common to all of the houses. No problem [not exactly, but permitted by code(s)].

Now your garage and house share the same water pipe. Your plans for wiring and grounding seem fine. The water pipe at the garage is an electrode, that is how you should think of it. The fact that it "bonds" both buildings together should not be an issue.

 

[charlie b]

I agree with Pierre. The question of whether the two buildings have metallic components (like water pipes) in common only comes into play if you do not wish to bring an EGC from the house to the garage. What you are describing is OK.

 

[jwelectric]

Wait a minute gentleman.

Looking at 250.32 real close I can not see where he would need to install a ground rod if this water pipe he has mentioned is a metal pipe.

250.32 refers to all the grounding electrodes that are present as outlined in 250.52(A)(1) through (A)(6). There is no mention to the Supplemental Electrode outlined in 250.53(D)(2) and 250.50 does not refer to 250.53.

Therefore if this water pipe is metal and he bonds to it, this is all that is required as outlined in the 2005 cycle of the NEC by 250.32

 

[charlie b]

I disagree, Mike. First of all, who you callin gentlemen? Dem's fighten words. :wink:

Even though 250.50 does not point you to 250.53, what 250.53 does is tell us how to install the Grounding Electrode System. You don't get to say "This paragraph does not apply because no other paragraph told me to read it."

Start with 250.50, and consider a single building comprising a single family residence. What would tell us to supplement the water pipe with a ground rod? We would have to go to 250.53, even though 250.50 did not tell us to go there.

 

[jwelectric]

I agree that when installing an electrode system for a dwelling unit or any other system that all of part III would apply.

With the installation of feeders to a remote building 250.32 is the section of the code that applies as the title states.

250.32 Buildings or Structures Supplied by Feeder(s) or Branch Circuit(s).

250.32 explains the procedure that we are to follow while installing this grounding electrode..

(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 250.50. 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.

250.32 only makes reference to 250.50 and does not mention any other part of part III of 250. Therefore the only part of 250 that would apply would be 250.50 and not 250.53.

I also agree that this was not the intent of panel 5 and I made a proposal to have the wording changed from ?installed in accordance with 250.50? to ? installed in accordance with part III of 250.?

 

[Pierre C Belarge]

Mike
Basically what you are saying is that water pipes do not need to be supplemented... I say that because of the reasoning you are using for separate buildings on a premises.

What the NEC says in a nutshell is:
If a building on a premises is supplied by a service or feeder, it is required to follow 250.50 [(250.32) shall have a grounding electrode or grounding electrode system installed according with 250.50]

In the case of the original poster, a water pipe is present. Water pipes are required to be supplemented.

 

[jwelectric]

Mike
Basically what you are saying is that water pipes do not need to be supplemented... I say that because of the reasoning you are using for separate buildings on a premises.

Using the reference outlined in 250.32 this is all that is required.
I am using red to quote the NEC.

250.32 Buildings or Structures Supplied by 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 250.50. 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.

250.32 only refers to 250.50 and no other section or article. This is all that is to be applied in this section. Was it the intent? I don?t know I only know that that is all that was referred to.

What the NEC says in a nutshell is:
If a building on a premises is supplied by a service or feeder, it is required to follow 250.50 [(250.32) shall have a grounding electrode or grounding electrode system installed according with 250.50]

The original post was asking about feeders not a service. When installing feeders to a separate building then 250.30 is the section that applies as outlined by its title. No where in 250.30 does it make reference to any other part of Part III it only directs us to 250.50. Nowhere in 250.50 are we required to go to a different section.

In the case of the original poster, a water pipe is present. Water pipes are required to be supplemented

When applying Part III of 250 I agree that 250.53 would apply to the water pipe but again we are not applying the whole of Part III we are only referenced to 250.50 from 250.32. Show me wording that would include 250.53 and I will agree with your statement.
The fact remains that 250.30 ONLY refers to section 250.50 and nothing else.

 

[iwire]

I agree with Mike, I think he is technically correct.

The wording in 250.32 only directs us to 250.50.

IMO he is correct it should direct us to Part III of 250.

I think we all believe that is intent and the logical inference. I don't see the words in the NEC to require it.

Mike, good luck with the change proposal. 8)

 

[jwelectric]

Thank you Bob I will be watching the ROPs and hope I get support during the comment stage.

 

[infinity]

I concur with both Bob and Mike. The words to support the logical application of supplementing the water pipe just aren't there.

 

[charlie b]

250.32 only makes reference to 250.50 and does not mention any other part of part III of 250. Therefore the only part of 250 that would apply would be 250.50 and not 250.53.

So I suppose that within that separate building we can use #12 wire and 25 amp breakers? After all, 250.32 does not send us to 240.4(D).

When any section refers you to another section, what it is saying is, (1) Go do what that other section tells you, and then (2) Go read the rest of the book and see if any other rules apply.

 

[jwelectric]

250.32 only makes reference to 250.50 and does not mention any other part of part III of 250. Therefore the only part of 250 that would apply would be 250.50 and not 250.53.

So I suppose that within that separate building we can use #12 wire and 25 amp breakers? After all, 250.32 does not send us to 240.4(D).

When any section refers you to another section, what it is saying is, (1) Go do what that other section tells you, and then (2) Go read the rest of the book and see if any other rules apply.

As this applies to 250.32 and its reference to 250.50 I would have to respectfully disagree with your statement.

250.32 directs us to the grounding electrode system found in 250.50

(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 250.50.

It would have been just as easy to use Part III in place of 250.50 and it would not have violated the Manual of Style.

I disagree with the wording of 250.32 and made my point know through a proposal to have the wording changed. I hope that I can depend on your support during the comment stage.

 

[jwelectric]

5-120 Log #1298 NEC-P05 Action: Accept
(250.32(A))
_______________________________________________________________________________________________
Submitter: Joseph Whitt, JW Electric
Panel Meeting Action: Accept

 

[gndrod]

Mike, So what is the inspector's edict...bond the H2o pipe? I laud you on your success with the Part III 250.50 clarification. That needed attention.
rbj,Seattle