Grounding a system question.

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JP490440

Member
Location
NW Oklahoma
I?m new here and haven?t been a journeyman for all that long. The company I work for took on some fairly large projects and I finished one shop and office building. I am now in a situation where I have had to go take over a half finished job from another journeyman who is causing problems with the other crews. He is highly skilled at talking and overcomplicating things.

Now I went and listened a bit to long and he has my head turned around on a few things.
Wye system

I?m installing a outdoor transformer + ground rod/ utility voltage to 480v 600a
Outdoor Auto transfer switch with a main disconnect and a bonding jumper setup + ground rod
Outdoor distribution panel 1 400a breaker for the offices and 1 200a + ground rod for a whole bunch of pole lights

Inside is a 480/277 lighting panel
75kv transformer Will be bonding in the transformer.
2 208/120 panels for general power.

I was going to parallel grounds, hots and neutrals from the ATS where the bonding jumper is and then bond the cold water, gas and building steel to the panel inside.
He?s telling me I ?have" to use the cold water pipe ( copper ) as a grounding electrode and building steel as well. I was planning on running my ground back to the ATS and hooking to the lugs were the bonding jumper is and the ground rod there.

Any help will be appreciated. I think I?m going to have to get the grounding and bonding series.
 

Smart $

Esteemed Member
Location
Ohio
...

I was going to parallel grounds, hots and neutrals from the ATS where the bonding jumper is and then bond the cold water, gas and building steel to the panel inside.
He’s telling me I “have" to use the cold water pipe ( copper ) as a grounding electrode and building steel as well. I was planning on running my ground back to the ATS and hooking to the lugs were the bonding jumper is and the ground rod there.

Any help will be appreciated. I think I’m going to have to get the grounding and bonding series.
Water pipe and structural steel are grounding electrodes. The conductors run to them are grounding electrode conductors (GEC's), as are any running to ground rods (unless they start at another electrode, then the conductors are [electrode] bonding jumpers). The most common bonding location for GEC's is where the main bonding jumper is located (service disconnecting means). At that location, you can bond the GEC's on either end of the jumper. Anywhere else, it has to be to bonded to the service entrance grounded conductor.
 
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JP490440

Member
Location
NW Oklahoma
Thanks, I appreciate it. How you described is the way I have always done it.
By the time this guy got done with an explanation how he always grounds and bonds a system ( which is the "only way" ) I had no idea how to spell my name.
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
A couple of Code references to check out, and comments:

For your utility supplied transformer and grounding of your 480 wye system, look at 250.24.
You will find your requirement for the transformer ground rod, bonding jumpers, etc. Note
250.24(A)(1) requires your grounding electrodes be connected from the end of the lateral to the
grounded service disconnect buss which in this case is your ATS. (or to another electrode)

For you 208/120 transformers, look at 250.30 for the bonding/grounding electrode requirements.
Note 250.30(A)(7) states the building steel or metal water pipe will be your grounding electrode for the transformers.
 

JP490440

Member
Location
NW Oklahoma
I think where the other gentelman and i differ is that he is saying that the cold water pipe has to be the primary grounding electrode and i was just bonding it. He was trying to get them to tear out a wall in order to get a bonding clamp on the pipe before its first coupler. I saw an exception thst allows you in commercial buildings to put the clamp on at a more convenient point. Like 4 feet later when it comes out if the wall and runs the full length of the building above the grid.

I did find those charts yesterday, they are kind if nice.

Thanks.
 

jxofaltrds

Senior Member
Location
Mike P. Columbus Ohio
Occupation
ESI
I think where the other gentelman and i differ is that he is saying that the cold water pipe has to be the primary grounding electrode and i was just bonding it. He was trying to get them to tear out a wall in order to get a bonding clamp on the pipe before its first coupler. I saw an exception thst allows you in commercial buildings to put the clamp on at a more convenient point. Like 4 feet later when it comes out if the wall and runs the full length of the building above the grid.

I did find those charts yesterday, they are kind if nice.

Thanks.

Sounds like the water line is isolated from the street. If so you are bonding.

He may be old school and think that the metal waterline is the best electrode.

No exceptions for commercial work. 250.52 is 250.52.
 

JP490440

Member
Location
NW Oklahoma
Yeah I did see 250.68C the exception is right under it. I have to admit my confusion though. I am in a commercial building and the first 8 feet of the water pipe are inside of a wall and not accessible.
 

Gregg Harris

Senior Member
Location
Virginia
He's probably thinking of 250.68(1) Exception...

...but that's for extending the GES to another electrode, not making the GEC connection.


250.52(A)(1) Exception In industrial, institutional, and commercial buildings where conditions of maintainance and supervision ensure only qualified persons service the installation, the entire length or the metal water pipe system can be used for grounding purposes, provided the entire length, other than short sections passing through walls,floors, or ceilings is exposed.
 

Smart $

Esteemed Member
Location
Ohio
250.52(A)(1) Exception In industrial, institutional, and commercial buildings where conditions of maintainance and supervision ensure only qualified persons service the installation, the entire length or the metal water pipe system can be used for grounding purposes, provided the entire length, other than short sections passing through walls,floors, or ceilings is exposed.
Hmmm...

That Exception was removed in the 2011 edition (which is the edition I referenced), but compliant for installations under 2005 and 2008 (with institutional added) editions. I see OK is still under the 2008 edition...
 
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jxofaltrds

Senior Member
Location
Mike P. Columbus Ohio
Occupation
ESI
250.52(A)(1) Exception In industrial, institutional, and commercial buildings where conditions of maintainance and supervision ensure only qualified persons service the installation, the entire length or the metal water pipe system can be used for grounding purposes, provided the entire length, other than short sections passing through walls,floors, or ceilings is exposed.

I do not have a 250.52(A)(1) Exception in my 2011 NEC.
 

JP490440

Member
Location
NW Oklahoma
In the 2011 what does 250.68 (c) 1. the exception say to you guys. To me it says you can connect to the cold water pipe more than 5ft from the entrance in a commercial building. And it can be used as a bonding or as a grounding electrode conductor. So once the pipe gets in the earth it becomes the grounding electrode? And its it’s own conductor? And I can tie on to closer to the panel? Or am I really missing the point?

Is electrolysis a concern? Honestly I’ve heard the term but have never experienced it other than having lake water eat up a sacrificial anode on a outboard.

This pipe meets the requirements of being mostly exposed above the drop ceiling and only having short sections of it passing through full height walls. Its a 2” copper water line.

Sorry if I’m beating a dead horse.
 

kwired

Electron manager
Location
NE Nebraska
I agree with most of what has been said by others up to this point. One other thing I want to bring up is about the transformer. It was only mentioned that it is outdoors, but no mention of where outdoors. Is it part of or right at the building in question or is it a separate structure? If it is a separate structure then it needs its own grounding electrode system at its location and the building needs a separate grounding electrode system run to the equipment grounding bus at the main panel or disconnect.

If it is part of the building in question then the disconnect for the primary of the transformer is actually your service or feeder disconnect for this building and the grounding electrode system should be run to there.
 

JP490440

Member
Location
NW Oklahoma
The primary transformer.
ATS with the main service disconnect 600A

And a MDP 400A building feed 200A pole light feed

And generator are 150ft from the building on a 45 ft long pad. A ground rod was driven at each location and I tied into the rebar in the pad and brought up a 1/0 copper wire into the ATS where the main disconnect is.

Inside is a 400A 480/277main lug only panel running a few lighting circuits it feeds 100A breaker to a 75kv transformer that powers two 225A panels that supply all of the 208/120 power.
 

Smart $

Esteemed Member
Location
Ohio
In the 2011 what does 250.68 (c) 1. the exception say to you guys. To me it says you can connect to the cold water pipe more than 5ft from the entrance in a commercial building. And it can be used as a bonding or as a grounding electrode conductor. So once the pipe gets in the earth it becomes the grounding electrode? And its it?s own conductor? And I can tie on to closer to the panel? Or am I really missing the point?

Is electrolysis a concern? Honestly I?ve heard the term but have never experienced it other than having lake water eat up a sacrificial anode on a outboard.

This pipe meets the requirements of being mostly exposed above the drop ceiling and only having short sections of it passing through full height walls. Its a 2? copper water line.

Sorry if I?m beating a dead horse.
Your member info indicates you are in NW Oklahoma, which is under the 2008 NEC (until November) from what I can discern. As posted above by Gregg Harris, the 2008 has the same-worded exception under 250.52(A)(1). You do not have to bond to the water pipe within 5 ft of entrance provided the conditions of the Exception are met.
 

kwired

Electron manager
Location
NE Nebraska
The primary transformer.
ATS with the main service disconnect 600A

And a MDP 400A building feed 200A pole light feed

And generator are 150ft from the building on a 45 ft long pad. A ground rod was driven at each location and I tied into the rebar in the pad and brought up a 1/0 copper wire into the ATS where the main disconnect is.

Inside is a 400A 480/277main lug only panel running a few lighting circuits it feeds 100A breaker to a 75kv transformer that powers two 225A panels that supply all of the 208/120 power.

I think I follow what you are describing.

Seems to me the ATS is the also the service disconnect. Also appears that it is at a separate structure from the main building being served. Grounding electrode system must be installed at each separate structure. You only need to use available electrodes that are at each structure, and if there is none then you must make one - ground rod is most popular choice but not the only option. Water lines, structural steel, etc. in the main building need to run to the main panel within the building and not back to the service located at a different structure. A separate grounded conductor (neutral) and equipment grounding conductor need to be run with the feeder to all other structures beyoned the service and no bonding jumper gets installed in the neutral. The GES of each structure is tied to the EGC at the main panel of each structure.
 
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