Electrolysis Damage Story [RE-wrenches]

[Dan Rice]

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Allan,

(I can hear the echo of  Mr. Wiles' voice...) "NEC section 110.3(B)
Installation and Use. Listed or labeled equipment shall be installed and
used in accordance with any instructions included in the listing or
labeling." Romex clamps are listed for a specific purpose -if you could get
ahold of the listing that applies, it would tell you specifically what
applications they're listed for. Though it's unseemly to speculate, I doubt
that they're listed for wet locations, and it's unlikely that one 1/2"
connector is listed for use with 4 USE-2 conductors along with a bare
ground.  Perhaps call Thomas & Betts or another manufacturer of your choice
to find out if the clamp was listed for this application. Getting ahold of
the actual listing specifications is another matter. According to the UL
General Information for Electrical Equipment Directory, "The basic standard
used to investigate products in this category is UL514B, "Fittings for Cable
and Conduit."" Text of the standard is $330 as a PDF, or $995 hardcopy
(price of paper going up) from UL.

My (admittedly halfass) suggestion for pole repair: Drop a measuring tape
into the pole -if concrete already fills the pole up to ground level, set a
new pole. Does the existing pole have rebar passing through the core below
ground level to keep it from turning in the cement? If so, sliding a 5" pole
into the existing 6" may not work. The 5" pole won't reach very far below
ground and may not provide enough bending strength. If the pole is hollow
all the way to the bottom, make a rebar cage to slide into the pole, and
fill with concrete -like a concrete freeway bridge pillar (with a rusty
steel casing on the outside). Six or eight pole-length #4 re-bars tied to
rebar rings of a diameter small enough to slide into existing pole -use two
or three rings as necessary, and add whatever cross pieces are necessary to
make the rebar cage into a manageable unit. Slide this into top of pole and
grout the pole full -use a vibrator (Makita makes a nice battery powered
small one) or agitate judiciously as you grout.

Good luck.

Dan Rice
Abundant Sun, LLC.
435-826-4565

----- Original Message ----- 
From: "Allan Sindelar" <allan at positiveenergysolar.com>
To: "New wrenches posting" <RE-wrenches at topica.com>
Sent: Thursday, May 05, 2005 7:06 PM
Subject: Electrolysis Damage Story [RE-wrenches]


Wrenches,
A simple mistake can have major consequences.

In 1997, in my first year of business, I designed and sold a SW4024-based
grid-tied system for a new home. As I wasn't licensed at the time, another
local electrical contractor with a history of doing solar installations was
separately contracted to pull the permit and do the installation. Upon
completion, I corrected a few things I didn't like (battery cables connected
at one end of the bank, rather than diagonally, for example) and have
supported the system and the customer in the years since. This is a good
customer.

The system has worked well, with only the Wattsun tracker and the E-Meter
requiring repair or replacement. The client called recently about tracker
malfunction, and today Mark (partner) went to the site to service it. What
he found was battery voltage at the tracker ground, which he determined was
from a ground fault at the array. The galvanic action caused by the fault
had rusted the 8-year-old 6" Sch 40 steel pole to the point that he could
poke a screwdriver through the pole at the base, and was concerned about the
whole thing toppling over any minute.

The cause of the ground fault was the use of two 1/2" Romex clamps for
strain relief where the USE-2 array input conductors entered a steel 3R
combiner box on the pole. Each of the two clamps held four #10 USE-2
conductors and one bare #8 or #10 grounding electrode conductor. One of the
clamps had shorted one of the PV+ conductors to ground. I am guessing that
it had been like this for a long time, maybe since installation, and I had
never detected the fault during routine service calls. An array GFDI wasn't
installed or required (and I'm not sure anyone even made one at that time).

The customer is looking at repair options for the pole, including outriggers
with driven steel posts and welded braces, and a poured concrete cap over
the base of the pole. We will head out soon to disassemble the array, to
reduce wind sail and the chance that it will come down, and to buy some time
 for a good repair to be devised. We are also looking at setting a 5" steel
pole inside the 6", with cement slurry between the two.

We haven't worked out a course of action yet. A couple of questions:

We use SO connectors for USE wire, and use Romex clamps for jacketed wire in
indoor locations. Is the use of Romex clamps on USE wire in this application
legal per NEC? What Code section addresses this?
If issues of liability and responsibility come up (and they probably will
not) who's liable? The contractor who installed the system and pulled the
permit? The inspector who signed off on the job? Us? How would you serve the
customer in this case? I supplied a one-year warranty on system design and
component failures, and the installer gave the same against failures due to
incorrect installation.

Has anyone ever repaired a rusted pole? Howdja doit, and did it work?

Thanks for any good advice. I'll share your responses with the client.

Allan at Positive Energy

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