FYI, I was going to get the sleeves, but they were special order and
required a special crimping tool. This project was in Mexico, so I
pulled the cable out and inspected it after it was torqued. I found
excellent compression, and no tearing of the strands. In my opinion,
the SMA connectors are good for fine stranded cable, even if they don't
have the UL listing.
Its one of those: I should have never asked, things. SMA was obligated
to say they were not fine strand rated, and I guess I was obligated to
worry.
R.Ray Walters
CTO, Solarray, Inc
Nabcep Certified PV Installer,
Licensed Master Electrician
Solar Design Engineer
303 505-8760
On 4/30/2014 12:01 AM, William Miller wrote:
Ray:
Darn good question, especially since I will be doing the exact same thing,
*tomorrow*.
I have never been clear on the real problem. Fine stranded cables overheat in
the wrong lugs? Is this true for mechanical or compression?
Aside from code compliance, what is the best common sense approach to Sunny
Islands with fine stranded? Annual retorquing? Pin terminals? Solder tinning
the strands?????
I used to wrap thin copper sheeting around fine stranded just to corral the
strands. Is this a possible solution?
Thanks Ray for bringing up a question I forgot to consider.
William
Miller Solar
On Apr 29, 2014, at 10:48 PM, Ray Walters <r...@solarray.com> wrote:
Hi All;
In order to avoid any of my work showing up in someone's slideshow of horrors,
I'm trying to find the correct way to wire 3 Sunny Islands with Cobra X flex
cable.
While it doesn't actually mention it in the SMA manual, a call to SMA tech
support confirmed my suspicions: the DC lugs in the inverter are NOT rated for
flex or fine stranded cable.
Both SMA and CED recommended I try Grainger's for crimp on adapters. Grainger
had no clue, and nothing came up in searches there.
From a trade show, I have an ILSCO lug book, that shows a crimp on pigtail
adapter. It does not mention whether its flex rated though on the crimp side
of the adapter, as the adapter is used primarily to land over sized cables into
smaller lugs. (2/0 to #1, for instance)
The best I've found so far, is NSI, which makes sleeves, that are installed
around the wire, right in the connection:
http://www.nsiindustries.com/products/electrical/connectors/compression-connectors/copper-compression/fsflex-cable-sleeve.aspx
I also found a Schneider white paper recommending sleeves with their lugs:
http://static.schneider-electric.us/docs/Circuit%20Protection/0515DB0301.pdf
So who has used these sleeves, and where do I get them?
The sleeves seem like a decent compromise, whilst the ILSCO pigtail adapters
are coming in at $40/ ea...... (ouch)
On the internet, I'm seeing several examples of X flex used directly (no
adapters) with the Sunny Islands, so are folks just blowing off articles
690.31(F) and 110.14, that specify the connector be rated for flex cable?
And finally, couldn't SMA use a lug that was flex rated?
For example, Marathon makes Class K rated mechanical Lugs:
http://www.marathonsp.com/NewRatings.html
I'd use THHN, but I really don't feel good about wiring the Heineman breakers
with that stiff a wire. I've cracked breaker cases before......that's why the
X flex is industry standard for off grid DC.
Thanks for your help,
--
R.Ray Walters
CTO, Solarray, Inc
Nabcep Certified PV Installer,
Licensed Master Electrician
Solar Design Engineer
303 505-8760
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