[RE-wrenches] Ferrules for large fine-stranded wire.

[Kirk Herander]

Hi Jay,

Yep, mersen and marathon brands, have similar fine strand DLO ratings on
some of their power terminal blocks. I’ve used both types before as I
recall.

I am traveling, but will try to post some spec sheets in the next few days.


*Kirk Herander / **kirkh at vermont.solar <kirkh at vermont.solar>*

*Owner|Principal, VT Solar, LLC*

*Celebrating our 34st Anniversary 1991-2025!!*

dba Vermont Solar Engineering

802.559.1225


On Wed, Sep 3, 2025 at 6:50 PM jay <jay.peltz at gmail.com> wrote:

> this got me curious.
>
> Here is the only picture I can find of anything rated for fine strand
> distrubution block.
> Notice it has an extension on the bottom of the compression screw.  Which
> I guess is keeping the find stands out of the threads.
>
>
> Nothing else I can find says it’s rated from fine strand.
>
> Happy to be proven wrong.
>
> jay
>
> hubbell.com
> <https://www.hubbell.com/burndy/en/products/bdblcs7r1dw-large-flex-rated-power-distribution-block/p/8517004>
> [image: apple-touch-icon.png]
> <https://www.hubbell.com/burndy/en/products/bdblcs7r1dw-large-flex-rated-power-distribution-block/p/8517004>
> <https://www.hubbell.com/burndy/en/products/bdblcs7r1dw-large-flex-rated-power-distribution-block/p/8517004>
>
>
> On Sep 3, 2025, at 3:56 PM, Kirk Herander <kirkh at vermont.solar> wrote:
>
> IMO, any OEM that recommends a ferrule does not use fine-strand rated
> compression lugs in their equipment.
>
> Rated lugs do exist, they just don’t seem to be spec’ed by OEMs.
>
> I don’t like ferrules on battery cable and always use fine-stranded
> compression PDBs when building custom battery combiners.
>
>
>
>
> *Kirk Herander / **kirkh at vermont.solar <kirkh at vermont.solar>*
> *Owner|Principal, VT Solar, LLC*
> *Celebrating our 34st Anniversary 1991-2025!!*
> dba Vermont Solar Engineering
> 802.559.1225
>
>
> On Wed, Sep 3, 2025 at 5:38 PM jay via RE-wrenches <
> re-wrenches at lists.re-wrenches.org> wrote:
>
>> From my memory none of the compression lug style are rated for fine
>> stand, at least without a ferrule.
>>
>> Because strands can get into the threads and bind, making it seam like
>> its tight but its not.
>>
>> But I could be wrong
>>
>>
>> On Sep 3, 2025, at 2:39 PM, Ray Walters via RE-wrenches <
>> re-wrenches at lists.re-wrenches.org> wrote:
>>
>> I've got to ask: Are none of the lugs on these Chinese inverters approved
>> for fine strand cable?  I just have not had a problem with that, but I've
>> mostly used Magnum, Midnite, and Outback equipment over the years.   What
>> were the lugs on the old Trace DC 250 boxes?  Were they fine strand rated?
>> They sure were tough to get 4/0 into, as William mentioned.
>>
>> Ray
>> Remote Solar
>> On 9/3/2025 12:57 PM, Kent via RE-wrenches wrote:
>>
>> William,
>>
>> If the only reason the ferrule wouldn't fit after using the hex crimper
>> was the ridge left where the dies meet, you could rotate the cable 120
>> degrees and crimp the ferrule again.
>>
>> I doubt that the indenter crimper will do a decent job with large
>> ferrules.
>>
>> I do like your thin piece of copper solution. Not UL approved but I dare
>> say wrench approved.
>> Kent Osterberg
>> Blue Mountain Solar
>>
>>
>> On 9/2/2025 8:55 PM, William Miller via RE-wrenches wrote:
>>
>> Friends:
>>
>>
>> Thank you for all of your input on this question.  I feel it only right I
>> report back how this turned out
>>
>>
>> I tried a crimper like this:
>>
>>
>>
>>
>>
>> It left a jagged ridge on both sides of the ferrule where the dies met.
>>
>>
>> The crimper below was suggested but I have not tried it:
>>
>> This was suggested but I have not tried it either:
>>
>>
>>
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