[RE-wrenches] Flexible stranded Connectors

Ray Walters ray at solarray.com
Tue Apr 29 22:48:28 PDT 2014


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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