[RE-wrenches] Incompatible Metals
Brian Wiley
btw at we-llc.com
Mon Jan 17 10:31:08 PST 2011
Hi Mick,
WEEB lugs can use either solid or stranded. One wire up to 6 AWG or two
wires of 10AWG.
Best Regards,
Brian Wiley
Wiley Electronics LLC
On 1/14/2011 8:15 PM, Mick Abraham wrote:
> Kindly bear with me as I go "back to basics". #10 cu has been my old
> standby for bonding the metal solar module frames but in recent years
> Arthur Ruden @ Sharp told me to use nothing smaller than #8. I don't
> know if other major PV mfr's have a similar spec or not but before I
> buy a spool...
>
> The new (and appealing) Tyco SolKlamp product calls for solid wire
> only, not stranded, if I recall correctly. I've never used the solid
> material because of the bending difficulty but I now wonder if other
> grounding methods: WEEB lugs, lay-in lugs, etc. also prefer the use of
> a solid grounding conductor instead of stranded.
>
> Opinions and education are welcomed. As always, the Wrench List is the
> Bomb!
>
> Mick Abraham, Proprietor
> www.abrahamsolar.com <http://www.abrahamsolar.com>
>
> Voice: 970-731-4675
>
>
> On Fri, Jan 14, 2011 at 12:45 PM, Kelly Keilwitz, Whidbey Sun & Wind
> <kelly at whidbeysunwind.com <mailto:kelly at whidbeysunwind.com>> wrote:
>
> Peter,
> Yes the #10 XHHW (2) we use is green-jacketed, and 90˚ rated. We
> get it through our local electrical supply house.
>
>
> Kelly Keilwitz, P.E.
> Whidbey Sun & Wind
> Renewable Energy Systems
> kelly at whidbeysunwind.com <mailto:kelly at whidbeysunwind.com>
> 360-678-7131
>
>
>
>
> On Jan 14, 2011, at 11:04 AM, Peter Parrish wrote:
>
> Great idea Kelly! I didn't know one could get green jacketed
> USE or XHHW. Do
> you have a source? Also, do you think that we might need wire
> rated "-2" for
> 90 deg C wet locations. I know that this is not a current carrying
> conductor, but roof tops are definitely 90 deg C wet
> environments. Your
> thoughts?
>
> - Peter
>
>
> Peter T. Parrish, Ph.D., President
> California Solar Engineering, Inc.
> 820 Cynthia Ave., Los Angeles, CA 90065
> CA Lic. 854779, NABCEP Cert. 031806-26
> peter.parrish at calsolareng.com
> <mailto:peter.parrish at calsolareng.com>
> Ph 323-258-8883, Mobile 323-839-6108, Fax 323-258-8885
>
>
> -----Original Message-----
> From: re-wrenches-bounces at lists.re-wrenches.org
> <mailto:re-wrenches-bounces at lists.re-wrenches.org>
> [mailto:re-wrenches-bounces at lists.re-wrenches.org
> <mailto:re-wrenches-bounces at lists.re-wrenches.org>] On Behalf
> Of Kelly
> Keilwitz, Whidbey Sun & Wind
> Sent: Friday, January 14, 2011 10:14 AM
> To: RE-wrenches
> Subject: Re: [RE-wrenches] Incompatible Metals
>
> Peter,
> I have never understood the common practice of using bare copper
> ground wire on and against aluminum frames and modules. It
> always has
> been a dissimilar metals issue. Just look anywhere copper has set
> against aluminum for awhile.
> We use #10 green jacketed Cu USE or XHHW conductor and strip
> away the
> jacket at each lug, using No-Ox on that section of bare wire
> at the
> lug. The wire can be tucked in to the module frames and with
> the PV
> conductors.
>
> Kelly Keilwitz, P.E.
> Whidbey Sun & Wind
> Renewable Energy Systems
> kelly at whidbeysunwind.com <mailto:kelly at whidbeysunwind.com>
> 360-678-7131
>
>
>
>
> On Jan 14, 2011, at 7:36 AM, Peter Parrish wrote:
>
> One of my students who is currently responsible for
> standing for
> inspection
> at their company encountered a inspector who made an
> interesting
> point about
> incompatible metals (i.e. copper and anodized aluminum).
>
> The PV system in question used outdoor rated lay-in lugs
> to bond the
> rails
> to bare copper wire (so far so good). The ground wire was
> then zip-
> tied to
> the rail to carry it to the point where it entered a
> junction box
> along with
> the rest of the PV conductors.
>
> The inspector was concerned with the fact that the bare
> copper was in
> contact with the aluminum rails and that this might cause
> galvanic
> corrosion
> and subsequent failure of the grounding.
>
> I have never encountered this issue before and I wonder if
> anyone
> else has
> and what was the outcome.
>
> As an aside: I do know that 10 AWG and 12 AWG solid bare
> copper
> wire can be
> purchased "pre-tinned" (maybe not tin per se, but coated).
> We did so
> by
> mistake. We used it up, but not before one inspector
> questioned its
> use for
> the purpose of grounding our system. We showed him the UL
> label on
> the spool
> and scraped off the coating to expose the copper core and that
> satisfied
> him. To this day I don't know if the use of this wire for
> grounding
> was
> among its intended purposes.
>
> - Peter
>
> Peter T. Parrish, Ph.D., President
> California Solar Engineering, Inc.
> 820 Cynthia Ave., Los Angeles, CA 90065
> CA Lic. 854779, NABCEP Cert. 031806-26
> peter.parrish at calsolareng.com
> <mailto:peter.parrish at calsolareng.com>
> Ph 323-258-8883, Mobile 323-839-6108, Fax 323-258-8885
>
>
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