[RE-wrenches] Grounding Top of Pole Mount Array with a Ufer

[frenergy]

I wasn't clear or accurate in my comment " a lot more surface area in 8" 
pipe 5-6 feet into the earth" which we have never done.  should have 
said "....5-6 feet into 1.5 yards of concrete embedded in the ground"  
Having seen many instances of steel in concrete from demo jobs, little 
or no rust is found where steel is encased in concrete, at least in 
these parts of the northern Sierra.

             That 2 sq ft X 1/4" thick bare steel plate or other 
accepted electrodes "shall be embedded below permanent moisture level" 
(that's pretty fuzzy) has been in the code for a long time, it must be 
there because it works.

Bill

Feather River Solar Electric
Bill Battagin, Owner
4291 Nelson St.
Taylorsville, CA 95983
530.284.7849
CA Lic 874049
www.frenergy.net

On 6/25/2021 9:16 AM, Ray wrote:
>
> Copper can get a pretty good oxide layer on it as well, but I'm not 
> versed in the science enough to know how any of that effects the 
> conductivity. Instead, I assume that the NEC has investigated 
> corrosion, and so we just follow the code. For plate electrodes 
> (250.52(A)(7)), it just specifies dimensions and thickness, and 
> specifically mentions bare iron or steel. 250.52(A)(3)(/1/) for 
> Concrete encased electrodes (UFER) also allows bare steel reinforcing 
> rod, while section (/2/) allows your #4 copper UFER.
>
> Lacking further information, I just go with the code, and my own 
> ground impedance measurements over the years.  My small sampling of 
> measurements has found steel rebar grounds and large steel pipe (4"D 
> and larger) to be under 25 ohms, while I have measured copper coated 
> rods as high as 700 ohms in dry soil.  I haven't measure copper UFER 
> or compared it to steel, so again, I don't know. It might be better 
> than steel, but all are allowed by code.
>
> Ultimately it might come down to soil and weather conditions for 
> different areas?
>
> Ray Walters
> Remote Solar
> 303 505-8760
> On 6/25/21 10:35 AM, Dana Orzel wrote:
>> That’s why we use the Ufer, our AHJ assumes that once a layer of rust develops this is not valid...........
>>
>>
>>
>> Dana Orzel                              Great Solar Works, Inc.
>> C - 208.721.7003dana at solarwork.com
>> Idaho Contractor - # 028765         Idaho PV # 028374
>> NABCEP # 051112-136www.greatsolarworks.com
>> "Responsible Technologies for Responsible People since 1988"
>>  Please consider the environment before printing this email.
>>
>>
>> -----Original Message-----
>> From: RE-wrenches<re-wrenches-bounces at lists.re-wrenches.org>  On Behalf Of Ray
>> Sent: Thursday, June 24, 2021 4:51 PM
>> To:re-wrenches at lists.re-wrenches.org
>> Subject: Re: [RE-wrenches] Grounding Top of Pole Mount Array with a Ufer
>>
>> We always put our assumption in our plan notes, based on our interpretation of 250.52(A)(7).  AHJs have never questioned it, and we also tie the pole to any rebar, so its all one big happy grounding electrode.
>>
>> Ray Walters
>> Remote Solar
>> 303 505-8760
>>
>> On 6/24/21 6:49 PM, frenergy wrote:
>>> Ray,
>>>
>>>              I couldn't agree more, its been my experience over the
>>> years that using 20 feet of #4 rebar in a building's footing was
>>> kosher and accepted NEC 250.52(3).  There's a heck of a lot more
>>> surface area in 8" pipe 5-6 feet into the earth than rebar in a
>>> foundation footing.  The ground at the bottom of the pole footing is
>>> also more likely to be damper.  Our AHJ has always accepted the steel
>>> pole as a ground rod....common sense prevails sometimes.
>>>
>>> Bill
>>>
>>> Feather River Solar Electric
>>> Bill Battagin, Owner
>>> 4291 Nelson St.
>>> Taylorsville, CA 95983
>>> 530.284.7849
>>> CA Lic 874049
>>> www.frenergy.net
>>>
>>> On 6/24/2021 7:31 AM, Ray wrote:
>>>> Usually a steel pole in concrete has enough surface area to qualify
>>>> as a plate electrode under 250.52(A)(7).  It needs to be at least 2
>>>> sq ft and 1/4" thick, and have an electrically conductive surface. So
>>>> we just drill and tap our ground connection into the pole, near the
>>>> combiner box.
>>>>
>>>> Ray Walters
>>>> Remote Solar
>>>> 303 505-8760
>>>>
>>>>


-- 
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.re-wrenches.org/pipermail/re-wrenches_lists.re-wrenches.org/attachments/20210625/11e566cc/attachment.htm>