Grounding on granite island [RE-wrenches]

Ray Walters walters at taosnet.com
Sat Apr 7 19:47:28 PDT 2007


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Oh we had ground rods in as far as we could get them, cut and set the  
left over piece its length from the original blah, blah, blah.   
Lightning usually comes before the rain, and dry soil over rock just  
has no conductivity. I'm shopping for a ground impedance tester to  
try and remove the guess work, but at $1500 they're hard to recoup  
the investment. I guess I could charge like the hospital, and each  
gadget that gets pulled out of the bag o' tricks gets billed out.....
I think the main thing in lightning protection is that we do our  
best, but there are no guarantees.  Don't forget whose idea it was to  
build on a hunk of granite in the first place.
I wouldn't lose sleep over it.

Ray


On Apr 7, 2007, at 2:50 PM, Ken Schaal wrote:

>
> Gee Ray, that really ruins my afternoon-----
>
> Bet it ruined yours more !
>
> What was at the working end of your ground wire?
>
> Thanks
> Ken
>
>
>
> ----- Original Message ----- From: "Ray Walters" <walters at taosnet.com>
> To: <RE-wrenches at topica.com>
> Sent: Saturday, April 07, 2007 1:52 PM
> Subject: Re: Grounding on granite island [RE-wrenches]
>
>
>>
>>
>> We did an installation on a rocky mountain top in West Texas  
>> several years ago. Same thing:  solid rock 6" below the surface.  
>> This system featured a 50 ft tall wind generator as well. We  
>> dutifully tied all  the grounds together, ran copper outside of  
>> the conduit to enhance  the conductivity to ground, put in  
>> polyphasor lightning protection, etc.
>> A lightning strike apparently to the wind generator sent a surge   
>> through the grounding system that took out 2 SW4024s, the charge   
>> controller, the Omnimeter, and the Kohler control for the generator.
>> After that, we ran a 1/2" steel cable  ( that's what they had   
>> already) and ran it from our existing ground system a 1/2 mile to  
>> a  steel cased well in the valley below. Seems to have done the  
>> trick,  as we haven't had any trouble since. That is a lot of  
>> cable, but that  was a lot of equipment taken out too.
>>
>> Ray Walters
>>
>>
>> On Apr 7, 2007, at 5:44 AM, Ken Schaal wrote:
>>
>>>
>>> Several years ago we designed and furnished an off grid 2 kw  
>>> system  for an extremely remote research facility in Gabon,  
>>> Africa. It is  located on a huge slab of rock in the middle of  
>>> the rain  forest ,with tall trees all around, on the equator and  
>>> miles from  the nearest dirt road. Most supplies were delivered  
>>> by helicopter.  All the buildings were built on piers on the  
>>> rock, so a Ufer was  not an option. Shallow wet ground was  
>>> several hundred feet away at  the edge of the rock and near a  
>>> shallow river. So we supplied a  large sheet of recycled heavy  
>>> gauge copper roofing with copper  grounding cable soldered to it,  
>>> and several clamps to attach a #4  copper ground wire from the  
>>> array and inverters. Surge protectors  were of course built in to  
>>> the Outback power panel . 302's I think,  probably should have  
>>> used the really good one's from Polyphaser, I  think.  
>>> Instructions were to bury this copper plate in as wet a   
>>> place ,and as deep, as possible. They have quite a few lightning   
>>> storms. So far they are quite pleased with the system, which  
>>> powers  the office and kitchen, including refrigeration. IE; It  
>>> hasn't been  zapped yet !
>>>
>>> My questions to the assembled wisdom of this group are;
>>> -- was this the best solution and/or could it be improved?
>>> --During the dry season, should they be sure to keep wet the  
>>> area  where it is buried ?
>>> --Should a lightning protection system, like those used on  
>>> houses,  be considered? Or is the marginal grounding point the  
>>> main issue?
>>> --What is the best way to test the effectiveness of the existing   
>>> ground system, including the path from PV panel to mounting  
>>> system  [ alum. rack on wooden support     structure] to ground  
>>> wire across  rock?
>>>        This wire by the way, was supposed to have been encased  
>>> in  latex modified cement mortar to fasten it to the rock so the  
>>> people  and elephants wondering thru         camp wouldn't  
>>> dislodge it !
>>> --What else should be considered?
>>>
>>> Everything has to be shipped by container from NY. We have some   
>>> smaller systems leaving in several weeks, and if improvements  
>>> are  to be made, this would be the time.
>>>
>>> Thank you in advance for your thoughts, and time.
>>>
>>> Ken Schaal
>>> CommonWealthSolar,LLC
>>>
>>>
>>>
>>> ----- Original Message ----- From: "Phil Undercuffler"  
>>> <p.undercuffler at conergy.us>
>>> To: <RE-wrenches at topica.com>
>>> Sent: Friday, April 06, 2007 10:59 PM
>>> Subject: RE: Grounding on granite island [RE-wrenches]
>>>
>>>
>>>>
>>>> Are they pouring concrete footers?
>>>>
>>>> Establish a Ufer ground by tying to the rebar in the  
>>>> foundation.  Here in
>>>> the dry Southwest, it's the preferred grounding method in the  
>>>> area --
>>>> fast, easy, effective and very nearly free.
>>>>
>>>> Have the concrete sub bend up a piece of the footing rebar, and  
>>>> leave
>>>> 9-10" exposed out of the slab in the area of the power system.    
>>>> Connect
>>>> to it with a two piece grounding "saddle" clamp, which makes a   
>>>> bronze to
>>>> steel connection, and keeps the copper conductor isolated from the
>>>> steel.
>>>>
>>>> Of course, if they aren't pouring a concrete foundation this  
>>>> wouldn't
>>>> help.
>>>>
>>>>
>>>> ------------------------------------------------------------------
>>>>
>>>> Phil Undercuffler
>>>> Technical Services Manager
>>>> Conergy, Inc.
>>>> 1730 Camino Carlos Rey Suite 103
>>>> Santa Fe NM 87507 USA
>>>> Office | 505.473.3800 x4841
>>>> Fax | 505.473.3830
>>>> www.conergy.us
>>>>
>>>> ------------------------------------------------------------------
>>>>
>>>> -----Original Message-----
>>>> From: Michael Welch [mailto:michael.welch at homepower.com]
>>>> Sent: Friday, April 06, 2007 10:57 AM
>>>> To: RE-wrenches at topica.com
>>>> Subject: Grounding on granite island [RE-wrenches]
>>>>
>>>>
>>>> Hi gang I an email awhile back about a grounding question, and a
>>>> follow-up phone call today.
>>>>
>>>> This fellow is building a PV/wind/generator system for small   
>>>> cottages on
>>>> a solid granite rock out on Lake Huron. His earth grounding  
>>>> plan  is to
>>>> haul a big steel plate out onto the ice (will need to do this  
>>>> pretty
>>>> soon) and let it sink to the lake floor as a way of grounding the
>>>> system.
>>>>
>>>> Or he may be able to submerge a plate in his graywater pool.
>>>>
>>>> There is no more than 6 inches of earth above the granite on the  
>>>> island.
>>>> He does not have access to the kind of equipment needed to drill  
>>>> deep
>>>> holes in the granite, but he can drill 6 or so inches deep.
>>>>
>>>> His RE dealer has been no help because of the unusual nature of the
>>>> problem, and he has not been able to get help from local electrical
>>>> engineers and electricians for the same reason.
>>>>
>>>> He wants to know if he is doing this correctly, and what size   
>>>> plates to
>>>> use, how many, and anything else you can think of.
>>>>
>>>> You can either respond here if you think it will be of interest  
>>>> to  the
>>>> list, or if you need more info and want to carry out an email
>>>> conversation with him, let me know off list and I will get you  
>>>> his email
>>>> address.
>>>>
>>>> Thanks in advance for your help.
>>>>
>>>>
>>>> ------------------------
>>>> Michael Welch
>>>> Sr. Editor
>>>>     Home Power magazine
>>>>     www.homepower.com
>>>>
>>>>
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>>>
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>>
>> R. Walters
>> Solarray.com
>> NABCEP # 04170442
>>
>>
>>
>> --
>> [Non-text portions of this message have been removed]
>>
>>
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>
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>

R. Walters
Solarray.com
NABCEP # 04170442	




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