Drake,
I have never seen significant damage due to rust, but ours is a dry
climate. But we had a real scary pole issue a few years ago.
In 1997, just starting out and before I was licensed, we hired
another PV pro to install a SW4024 GTWB system for us. He used a
Romex connector for strain relief on some USE-2 array wiring into an
array combiner box. The PV input conductors were direct-burial USE,
not in conduit and without a bonding conductor between the array and
the BOS. There was a #6 bare from the combiner to a ground rod at
the array.
The Romex connector pinched through the insulation on one array
conductor, causing a low-voltage ground fault. This leakage couldn't
be detected from the BOS in the house. The ground #6 carried this to
the rod for maybe ten years. It finally failed from electrolytic
corrosion and weather exposure, and once it did the 6" sch. 40 array
pole had the electrolytic reaction and began aggressively rusting
out from the inside. We discovered bubbling of the steel around the
base of the pole and the tech that day stuck a screwdriver right
through the pole at the base.
Needless to say, that array was taken down that day. The customer
poured a base up a foot around the pole, and filled it with rebar
and concrete, and it's good.
Allan
Allan Sindelar
[email protected]
NABCEP Certified Photovoltaic
Installer
NABCEP Certified Technical Sales Professional
New Mexico EE98J Journeyman Electrician
Positive Energy, Inc.
3201 Calle Marie
Santa Fe, New Mexico 87507
505 424-1112
www.positiveenergysolar.com
On 7/27/2011 3:40 PM, Drake wrote:
I've not personally seen any pole mount pipes that were bent or
broken. Has anyone seen this? How common is it? What
sort of damage to pole mount arrays is common?
At 05:25 PM 7/26/2011, you wrote:
I can confirm that
quite a bit
of water builds up inside the pipe.
A few times on rewiring old systems, we used self tapping screws
to
attach conduit and combiner boxes to the existing pole, and
we've had
water start running out the hole when it was close to the
ground. This
was in a dry climate (New Mexico) This was with a rack that
didn't cap
the pole, but I was still surprised how much water was in there.
(gallons)
Filling with concrete does seem to be a good idea, but I'll
point out its
not as easy as it sounds.
The concrete just pours out the bottom into the footing, as you
keep
filling it from the top. Pouring in a foot of gravel in the
bottom first
would help, or filling the pipe after the footing dried some
would do it
too.
No free lunch,
R. Walters
[email protected]
Solar Engineer
On Jul 26, 2011, at 2:08 PM, Dave Palumbo wrote:
> Roy,
>
> I have heard that the small amount of water from
condensation will
be absorbed by the concrete itself. Don't know for an absolute
fact that
this is true though.
>
> Dave
>
> -----Original Message-----
> From: [email protected]
[
mailto:[email protected]] On
Behalf Of Roy
Rakobitsch
> Sent: Tuesday, July 26, 2011 3:17 PM
> To: RE-wrenches
> Subject: Re: [RE-wrenches] pole mounts
>
> I would think that adding concrete partially up the pole
would cause
water
> and condensation to collect near the bottom and not drain
properly.
This
> could possibly lead to freezing and the pipe being blown
out or
damaged,
> even if the top is completely capped. I would think that
you should
either
> completely fill the pipe, or leave it empty with a good
layer of
gravel at
> the bottom to allow it to drain properly. I also have no
studies to
back
> this up, but it was just a thought.
>
> Roy Rakobitsch
> NABCEP Certified Small Wind Installer®
> NABCEP Certified Solar PV Installer®
> NYSERDA eligible Small Wind installer
> Wind/PV Design Engineer
> Windsine Inc.
> 631-514-4166
>
www.windsine.org
>
> On Tue, July 26, 2011 3:05 pm, Dave Palumbo wrote:
>> Todd,
>>
>>
>>
>> We add concrete inside of our steel pipe masts, up to
grade
level, in the
>> interest of having more weight below ground level. I
wouldn’t
say that
>> it made the pipe stronger (that better be strong enough
as is)
but more
>> weight down low will help keep it rooted in a big wind
event.
>>
>>
>>
>> Dave
>>
>>
>>
>> From: [email protected]
>>
[
mailto:[email protected]] On
Behalf Of
>> [email protected]
>> Sent: Tuesday, July 26, 2011 2:50 PM
>> To: RE-wrenches
>> Subject: [RE-wrenches] pole mounts
>>
>>
>>
>> Wrenches,
>>
>>
>>
>> Fact or fiction: Adding concrete to the inside of a
pole mount
pipe makes
>> it stronger.
>>
>>
>>
>> Thanks,
>>
>>
>>
>> Todd
>>
>>
>>
>>
>> Sent from Finest Planet WebMail.
>>
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>
>
>
>
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Drake
Chamberlin
ATHENS ELECTRIC
OH License
44810
CO license 3773
NABCEP Certified PV
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