It's not my intention to play devil's advocate or be contentious so allow me to clarify my point about liability shields.
Once the metal contact pin is pushed into the plastic housing and locks into place, you cannot visually or physically inspect the internal metal crimp barrel without dismantling or destroying the connector. This means that the integrity of the connection is only questioned if it fails. Despite Rennsteig being the industry gold standard and the OEM manufacturer of the Staubli tool it has a different marking which identifies the crimp as being made by the particular Rennsteig die. The Staubli and Rennsteig dies are manufactured to the exact same spec other than the marking which is verifiable. This means the integrity of the connection is functionally no different and legitimizes it for field installation from an NEC perspective. It also means that Staubli is under no obligation to honor any warranty or accept liability for any failure(an absolute necessity from a business standpoint). The only reason an installer would point the finger at the connector would be if there was a catastrophic failure and they didn't want to accept responsibility(which is why they have insurance). • The Stäubli Perspective: Because the stamp clearly identifies the tool as a Rennsteig and not an official Stäubli tool, it provides Stäubli with the exact evidence they need to legally void their manufacturer warranty if a terminal failure occurs. • The Inspector Perspective: For local AHJ electrical inspectors(whose interpretation of the NEC decides what is/isn't code compliant, the Rennsteig signature serves as proof of a high-quality, code-compliant, and precision-engineered connection that satisfies NEC 110.3(B) requirements. All that being said, from an experienced installers perspective, if you have to consider this potential scenario based on the scale of your jobs or the experience level of your employees, it's probably worth either buying the Staubli branded(Rennsteig manufactured) tool or raising your insurance coverage or both. Either way it's only a liability shield. The tools are manufactured by the same company to the same specifications. Sunny Regards, Tyrone Houck Oregon Solarworks LLC CCB #204937 LRT #076 On Tue, Oct 6, 2026, 5:21 AM Jason Szumlanski < [email protected]> wrote: > I agree that installer error is the primary cause of bad MC4 crimps, not > whether a $500, $300, or $30 crimper was used. That said, the rules are the > rules. And this one is broken as a matter of routine. > > > Jason Szumlanski > Principal Solar Designer | Florida Solar Design Group > NABCEP Certified Solar Professional (PVIP) > Florida State Certified Solar Contractor CVC56956 > Florida Certified Electrical Contractor EC13013208 > > > > > On Mon, Oct 5, 2026 at 7:33 PM Tyrone Houck <[email protected]> wrote: > >> It seems like a good time to mention that Rennsteig makes the Staubli >> crimp and dies to the exact same specifications as their own, excepting the >> stamp. Rennsteig made their crimper for Multi Contact/Staubli from the >> origin and through the entire history of the MC4 connector long before >> Staubli changed the name from Multi Contact to Staubli. It's the same die >> spec with/without an inspection stamp... >> I am of the opinion that if a connector fails under normal conditions it >> is 99.99+% of the time an installer error. Staubli vs rennsteig is not >> going to determine if a connector fails and a seasoned installer knows what >> a good crimp is and is effectively standing behind every connection they >> make anyway. >> >> It seems like the larger discussion is one of liability shields and >> accountability. >> >> >> Sunny Regards, >> >> Tyrone Houck >> Oregon Solarworks LLC >> CCB #204937 LRT #076 >> >> On Mon, Oct 5, 2026, 3:45 PM William Bryce <[email protected]> >> wrote: >> >>> My issue is with someone like Glen using this forum to act as a >>> code-enforcement representative, calling out installers he knows nothing >>> about in a disrespectful manner. >>> >>> I agree with his interpretation of a rule, But the real reason for this >>> rule was not to create a monopoly using the rule to sell extremely >>> overpriced tools. The professional approach would have been to explain your >>> thoughts of the requirements and educate, much like Bryan’s response from >>> PV-Cables. >>> >>> That said, I’ll put my Rennsteig tool up against the overpriced OEM tool >>> any day. >>> >>> I’ve been around long enough to know that people in glass houses >>> shouldn’t throw stones. This is a professional forum and a valuable >>> resource. Let’s keep the discussion respectful and useful, without letting >>> it turn into the kind of arguing we see on the DIY Solar Forum. >>> >>> I personally know Zeke, he is a professional installer and his installs >>> are top notch. >>> >>> >>> -William >>> >>> >>> >>> On Mon, Oct 5, 2026 at 5:36 PM Dana Orzel <[email protected]> wrote: >>> >>>> This friendly conversation brings up a good point and that is just >>>> because one manufactures crimper used with their crimp versus another >>>> manufacturers crimper used with their crimp. Versus one manufacturers >>>> crimper with another manufacturers crimp. >>>> There is no STANDARD that I am aware of. Has anybody ever done >>>> calibrated pull tests? Has the NEC done pull tests? >>>> When crimping OO & OOOO cable ring ends onto wire. I’m definitely not >>>> using an end that is manufactured by the same manufacturer as my crimper >>>> that I’ve had for 25 years. >>>> Is this a violation of the NEC? >>>> I do a manual pull test (tug) but I think that’s definitely subjective. >>>> >>>> >>>> Sent from my iPad >>>> >>>> On Oct 5, 2026, at 1:41 PM, Glenn <[email protected]> wrote: >>>> >>>> >>>> If bringing attention to what should not be done by professional >>>> installers, and pointing out code non-compliance is considered to be not >>>> friendly, then so be it. >>>> >>>> I have inspected too many installations where adherence to >>>> manufacturers required installation instructions have been 'overlooked, >>>> ignored or we've alwys done it that way' were inadequate responses. >>>> >>>> If a manufacturer lists its required method of assembly and >>>> installation and you interpret it as being a suggestion, it is clearly a >>>> violation of the NEC article 110.3b. >>>> >>>> Everyone takes their own level of responsibility for adherence and >>>> ultimately their accountability for their actions, obviously. However >>>> blatently posting such choices does zero for the reputation of our industry >>>> and needs to be avoided. >>>> >>>> I stand by my previous post. >>>> >>>> -Glenn >>>> >>>> On Oct 5, 2026 15:09, William Bryce <[email protected]> >>>> wrote: >>>> >>>> Glenn, >>>> >>>> That was quite the "friendly" response (not so much)! >>>> >>>> If using my Amazon purchased tool made by Rennsteig that has the exact >>>> die crimp design and compression ever comes into question, I'll take that >>>> hit! >>>> The goal of 110.3(B) is to make sure things are done correctly, to the >>>> recommended MFG specifications. In this case, a positive crimp of the MC4 >>>> connector to avoid loose connection, heat, and fire. >>>> >>>> Not to support a company's monopoly of a tool and their bottom line. >>>> >>>> I'm pretty sure that not everyone on this forum uses the Staubli tool. >>>> >>>> >>>> >>>> >>>> >>>> On Mon, Oct 5, 2026 at 2:19 PM Glenn <[email protected]> wrote: >>>> >>>> Why would you admit to violating NEC 110.3b here? >>>> That seems like a poor business decision. >>>> >>>> -Glenn >>>> >>>> On Oct 5, 2026 13:49, Zeke Yewdall <[email protected]> wrote: >>>> >>>> I've always just made them up myself -- CED Greentech carries the real >>>> MC4 connectors and the wire. My crimper is the amazon one, not the >>>> official staubli one. >>>> >>>> Or PV-cables.com has all sorts of custom ones with custom ends of any >>>> sort. >>>> >>>> Zeke >>>> >>>> >>>> _______________________________________________ >>>> List sponsored by Redwood Alliance >>>> >>>> Pay optional member dues here: http://re-wrenches.org >>>> >>>> List Address: [email protected] >>>> >>>> Change listserver email address & settings: >>>> >>>> https://lists.re-wrenches.org/mailman/options/re-wrenches_lists.re-wrenches.org/ >>>> >>>> There are two list archives for searching. When one doesn't work, try >>>> the other: >>>> https://www.mail-archive.com/[email protected]/ >>>> >>>> https://lists.re-wrenches.org/pipermail/re-wrenches_lists.re-wrenches.org/ >>>> >>>> List rules & etiquette: >>>> http://www.re-wrenches.org/etiquette.htm >>>> >>>> Check out or update participant bios: >>>> http://www.members.re-wrenches.org >>>> >>>> >>>> _______________________________________________ >>>> List sponsored by Redwood Alliance >>>> >>>> Pay optional member dues here: http://re-wrenches.org >>>> >>>> List Address: [email protected] >>>> >>>> Change listserver email address & settings: >>>> >>>> https://lists.re-wrenches.org/mailman/options/re-wrenches_lists.re-wrenches.org/ >>>> >>>> There are two list archives for searching. When one doesn't work, try >>>> the other: >>>> https://www.mail-archive.com/[email protected]/ >>>> >>>> https://lists.re-wrenches.org/pipermail/re-wrenches_lists.re-wrenches.org/ >>>> >>>> List rules & etiquette: >>>> http://www.re-wrenches.org/etiquette.htm >>>> >>>> Check out or update participant bios: >>>> http://www.members.re-wrenches.org >>>> >>>> _______________________________________________ >>>> List sponsored by Redwood Alliance >>>> >>>> Pay optional member dues here: http://re-wrenches.org >>>> >>>> List Address: [email protected] >>>> >>>> Change listserver email address & settings: >>>> >>>> https://lists.re-wrenches.org/mailman/options/re-wrenches_lists.re-wrenches.org/ >>>> >>>> There are two list archives for searching. When one doesn't work, try >>>> the other: >>>> https://www.mail-archive.com/[email protected]/ >>>> >>>> https://lists.re-wrenches.org/pipermail/re-wrenches_lists.re-wrenches.org/ >>>> >>>> List rules & etiquette: >>>> http://www.re-wrenches.org/etiquette.htm >>>> >>>> Check out or update participant bios: >>>> http://www.members.re-wrenches.org >>>> >>> _______________________________________________ >>> List sponsored by Redwood Alliance >>> >>> Pay optional member dues here: http://re-wrenches.org >>> >>> List Address: [email protected] >>> >>> Change listserver email address & settings: >>> >>> https://lists.re-wrenches.org/mailman/options/re-wrenches_lists.re-wrenches.org/ >>> >>> There are two list archives for searching. When one doesn't work, try >>> the other: >>> https://www.mail-archive.com/[email protected]/ >>> >>> https://lists.re-wrenches.org/pipermail/re-wrenches_lists.re-wrenches.org/ >>> >>> List rules & etiquette: >>> http://www.re-wrenches.org/etiquette.htm >>> >>> Check out or update participant bios: >>> http://www.members.re-wrenches.org >>> >> _______________________________________________ >> List sponsored by Redwood Alliance >> >> Pay optional member dues here: http://re-wrenches.org >> >> List Address: [email protected] >> >> Change listserver email address & settings: >> >> https://lists.re-wrenches.org/mailman/options/re-wrenches_lists.re-wrenches.org/ >> >> There are two list archives for searching. When one doesn't work, try the >> other: >> https://www.mail-archive.com/[email protected]/ >> https://lists.re-wrenches.org/pipermail/re-wrenches_lists.re-wrenches.org/ >> >> List rules & etiquette: >> http://www.re-wrenches.org/etiquette.htm >> >> Check out or update participant bios: >> http://www.members.re-wrenches.org >> > _______________________________________________ > List sponsored by Redwood Alliance > > Pay optional member dues here: http://re-wrenches.org > > List Address: [email protected] > > Change listserver email address & settings: > > https://lists.re-wrenches.org/mailman/options/re-wrenches_lists.re-wrenches.org/ > > There are two list archives for searching. When one doesn't work, try the > other: > https://www.mail-archive.com/[email protected]/ > https://lists.re-wrenches.org/pipermail/re-wrenches_lists.re-wrenches.org/ > > List rules & etiquette: > http://www.re-wrenches.org/etiquette.htm > > Check out or update participant bios: > http://www.members.re-wrenches.org >
_______________________________________________ List sponsored by Redwood Alliance Pay optional member dues here: http://re-wrenches.org List Address: [email protected] Change listserver email address & settings: https://lists.re-wrenches.org/mailman/options/re-wrenches_lists.re-wrenches.org/ There are two list archives for searching. When one doesn't work, try the other: https://www.mail-archive.com/[email protected]/ https://lists.re-wrenches.org/pipermail/re-wrenches_lists.re-wrenches.org/ List rules & etiquette: http://www.re-wrenches.org/etiquette.htm Check out or update participant bios: http://www.members.re-wrenches.org
