# 600 amp residential grounding requirements



## Jeep (Jul 23, 2012)

Greetings all... I could use a little help please... 

We primarily deal with repairs and servicing of existing electrical, however we came across a job that needs to have the 5 socket meter panel replaced for Townhouse HOA... 

Since we want to minimize the amount of time the residents are without power, we can not afford to fail the City inspection and delay the Meter Release, so I want to make sure that everything is correct before we call for the inspection. If you can review and correct me on the following, that would be greatly appreciated... 

The building is a 4 unit residential complex with a 600 amp panel located in the outside electrical closet... The building was built sometime in the 1980's. 

Each breaker is a 125A Zinsco feeding the individual subs... and one of the breakers burnt up the buss bar, thus requiring the replacement of the panel. 

There is one CEE located inside the electrical closet and just below the panel with what I believe to a be a 2/0 aluminum that runs from the meter panel to an acorn on the CEE... there is a seperate (cut) 2/0 that runs from the same acorn into the building... where it terminate inside the building is unknown at this time. (I'm assuming they are using this as the primary ground method. 

Each residential unit has its own metered, copper, fresh water feed located near the front door and none appear as being used as a grounding source.. At least on the outside of the building. 

In order to install a ground to these fresh water sources, we would need to conduit and surface mount approx 200 linear feet of 2/0. 

Each residential unit has its own indoor water heater that is not bonded between the hot and cold side.. 

Lastly, there is 4 *unprotected* 1/0 Service cable coming out of the plywood wall inside the electrical closet and into the bottom side of the meter panel for each of the units.. 

Question #1 Can I install two grounding rods near the closet or does it need to have a the ground ran to the fresh water copper pipes?

Question #2 Since the building does not have a common hot water heater, is it my responsibilty to bond the hot/cold pipes inside each of the units?

Question #3 Does the new codes require protection of the Service cables inside the electrical closets? 

Thank you in advance for your assistance and help


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## Southeast Power (Jan 18, 2009)

Here at the service entrance, it would be 1/0 copper or 3/0 Al to the closest cold water pipe.
After that, #6 green or bare copper to two ground rods. 
I don't know anything about what you are doing with water heaters in the Apartment's.

My opinion is that if someone runs anything more than a #6 to a ground rod, they are being wasteful.


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## Jeep (Jul 23, 2012)

Southeast Power said:


> Here at the service entrance, it would be 1/0 copper or 3/0 Al to the closest cold water pipe.
> After that, #6 green or bare copper to two ground rods.
> I don't know anything about what you are doing with water heaters in the Apartment's.
> 
> My opinion is that if someone runs anything more than a #6 to a ground rod, they are being wasteful.


Thank you for your answer... 

This is where I need help... I thought I read somewhere in section 250 that a CEE (concrete encased electrode) could be used instead of a 1/0 connection at the cold water supply... 

Is that correct?


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## Going_Commando (Oct 1, 2011)

Jeep said:


> Southeast Power said:
> 
> 
> > Here at the service entrance, it would be 1/0 copper or 3/0 Al to the closest cold water pipe.
> ...


The water piping still needs to be bonded, if present. You can use concrete encased electrodes as your supplemental instead of ground rods.


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## Cow (Jan 16, 2008)

It's really in your best interest to call and talk to the inspector that will be looking it over. 



Every time I've called the inspector on something up front, it seemed like they appreciated getting a heads up on what's coming up as well as a chance to give their two cents to help the inspection go smoother.


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## Southeast Power (Jan 18, 2009)

Jeep said:


> Thank you for your answer...
> 
> This is where I need help... I thought I read somewhere in section 250 that a CEE (concrete encased electrode) could be used instead of a 1/0 connection at the cold water supply...
> 
> Is that correct?


Where are you going to get one of those concrete encased electrodes?


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## 3DDesign (Oct 25, 2014)

Southeast Power said:


> Here at the service entrance, it would be 1/0 copper or 3/0 Al to the closest cold water pipe.
> After that, #6 green or bare copper to two ground rods.
> I don't know anything about what you are doing with water heaters in the Apartment's.
> 
> My opinion is that if someone runs anything more than a #6 to a ground rod, they are being wasteful.


Here, the 1/0 copper would go to the line side of the water meter and jump it in one continuous run, not the closest water line, unless the water line entering from underground is plastic.


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## Jeep (Jul 23, 2012)

thank you guys... I do have a call into the City to see what we can work out..


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## Switched (Dec 23, 2012)

1) If you have metal water piping, the city will likely require you to bond that to the main service. 

2) If your upgrading the service and not the individual units, then they may not make you bond all the metal piping for the units themselves. You don't have to do it at the WH, most inspectors in Cali just prefer it so they don't have to crawl around looking at the connections. (Most places in Cali also do not allow you to bond the water and gas lines through a water heater or other appliance).

3) They may let you slide on the feeders, but not in my experience. We usually have to set J-boxes or gutters and run the feeders into them, then into the panel. Splicing typically necessary. Not sure where you're at, but most jurisdictions in the Bay anything below 8' is subject to damage, so it must be protected by some method.


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## Jeep (Jul 23, 2012)

Southeast Power said:


> Where are you going to get one of those concrete encased electrodes?


It is the primary source of ground now and was installed by the original contractor


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## Jeep (Jul 23, 2012)

Switched said:


> 1) If you have metal water piping, the city will likely require you to bond that to the main service.
> 
> 2) If your upgrading the service and not the individual units, then they may not make you bond all the metal piping for the units themselves. You don't have to do it at the WH, most inspectors in Cali just prefer it so they don't have to crawl around looking at the connections. (Most places in Cali also do not allow you to bond the water and gas lines through a water heater or other appliance).
> 
> 3) They may let you slide on the feeders, but not in my experience. We usually have to set J-boxes or gutters and run the feeders into them, then into the panel. Splicing typically necessary. Not sure where you're at, but most jurisdictions in the Bay anything below 8' is subject to damage, so it must be protected by some method.


Like I said... I have a call into the City of San Jose now.. for clarification.. 

And I agree with you about bonding the cold water as it enters the building.. The problem is I have 4 seperate feeds... one each for the 4 residential units.. So it should require bonding to the closest, but the closest is 150 (LF) away and will need to be surface mounted to the exterior of the upscale community.. 

Bonding thru a hot water heater is not the goal.. It was explained that you're bonding the hot to the cold incase the hot water heater is ever removed.. 

The feeders are also a concern because if they need to be protected, this will for sure delay the replacement process.. I'm hoping that being grandfathered and inside a locked electrical closet will help to exempt.. 

Thanks Brother


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## Switched (Dec 23, 2012)

Jeep said:


> Like I said... I have a call into the City of San Jose now.. for clarification..
> 
> And I agree with you about bonding the cold water as it enters the building.. The problem is I have 4 seperate feeds... one each for the 4 residential units.. So it should require bonding to the closest, but the closest is 150 (LF) away and will need to be surface mounted to the exterior of the upscale community..
> 
> ...


We work in San Jose, they are more than likely going to make you protect them. They don't care about grandfathering, your working on it, you'll need to bring it current. 

They will make you bond the gas, cold, hot. You don't have to do it at the WH, but it makes it easy for them to verify. Also, depending upon which inspector you get, makes them less of a PITA.:wink:

The last one I did like this in SJ they wanted each units panel to be bonded to the main water line for their respective units. 

Hope that helps!


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## Dennis Alwon (May 9, 2009)

Jeep said:


> 's.
> 
> There is one CEE located inside the electrical closet and just below the panel with what I believe to a be a 2/0 aluminum that runs from the meter panel to an acorn on the CEE... there is a seperate (cut) 2/0 that runs from the same acorn into the building... where it terminate inside the building is unknown at this time. (I'm assuming they are using this as the primary ground method.


I hope it is not an aluminum wire used for a concrete encased electrode. Non compliant 250.66(B) as well as 



> *250.64
> (A) Aluminum or Copper-Clad Aluminum Conductors. Bare
> aluminum or copper-clad aluminum grounding electrode
> conductors shall not be used where in direct contact with
> ...


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## Dennis Alwon (May 9, 2009)

I suspect they connected the aluminum to a piece of $4 copper somewhere... No need to be 2/0 either


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## Jeep (Jul 23, 2012)

Hi All... Thought I'd give you an update as to the status of the OP... 

The City required ground to water pipe entering the building... They did not care there was an existing CEE in place, however I was able to use the CEE as one of the required ground rods.. 

The City required us to increase the ground cable from 1/0 to 3/0. The service cable size from our utility company is a 700 mil, which requires the 1/0 cable, however our Inspector wanted the 3/0 upgrade because the panel is rated up to 600A... I probably could have argued or appealed this, however getting the meter releases was more important so we complied.. 

The Romex feeders for each unit did need to be protected... I questioned using metallic flex conduit from the wall of the building to the bottom of the meter panel. The inspector came back with building a wooden type box under the panel to enclose the exposed Romex... 

On top of all that, we needed to submit affidavits from each resident stating they all having working smoke/CO2 detectors.. 

So thanks for everyone's help and advice.. the job is done and signed off


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