Mating connectors from different manufacturers - Common but not recommended? - Page 1
Forum section: electronics / projects

author: tinfever
author_rank: Regular Contributor
timestamp: May 03, 2023, 07:52:55 pm
content: The PC hardware industry seems to rely on compatibility of 4.2mm pitch connectors and crimp terminals between many different manufacturers and different ratings (high-current vs normal). However, I suspect if you asked any single manufacturer about such compatibility, they'd tell you not to do that. Is it that common to rely on undocumented compatibility between connectors? How does this actually work without failures everywhere?

author: coromonadalix
author_rank: Super Contributor
timestamp: May 04, 2023, 07:01:22 am
content: you have to search all their specs, pins sizes etc ... before using them, if choosen carefully i would not expect problemswe do at my job no problems for power stuffbut for sure quality has taken some beating .... mostly stuff coming from china at low pricing ... quality is low, metal thickness is lower ...simply put, dont cut in quality vs known good brands / vs cheap pricesare you talking about the "fire connector" loll on video cards

author: TheUnnamedNewbie
author_rank: Super Contributor
timestamp: May 04, 2023, 08:50:39 am
content: I can't answer for the specific PC motherboard/GPU connector example, but in general: Standards, standards, and standards. The world is full of examples of standardized connectors from various suppliers. In some markets (automotive) it is even a requirement to have multiple suppliers for a connector, they refuse to deal with a single-sourced component for something that is not a huge differentiator.Just think of the examples: USB, HDMI, power sockets, LC/SC fiber connectors, the sockets for lights, SMA connectors for antennas, BNC connectors on equipment, RJ45 connectors for your ethernet-over-twisted-pair, FAKRA... the list goes on.Some of these were really developed as a standard first (HDMI, USB, etc). Some come from a single company (eg, a lot of the coaxial connectors came out of HP/Aglient/Keysight or Anritsu) but then opened up, either as a license (I believe this is the case with some POF connectors, where broadcomm holds the license) or free. And sometimes you just have connectors that are copied and not protected or even officially licensed. Examples include TRS connectors that used to be used in every audio device ever (up to the point that BLE took over).

author: tooki
author_rank: Super Contributor
timestamp: May 04, 2023, 12:33:29 pm
content: Quote from: tinfever on May 03, 2023, 07:52:55 pmThat’d be an incorrect assumption. In the datasheets/catalogs, you do occasionally find mention of compatibility with competing manufacturers. And many manufacturer websites have competitor cross-reference lookups (though I have rarely found them to be useful.)

author: tinfever
author_rank: Regular Contributor
timestamp: May 04, 2023, 05:41:38 pm
content: Quote from: coromonadalix on May 04, 2023, 07:01:22 amI get choosing parts carefully to stay within their specs, but I'm concerned about subtle incompatibility between connectors are terminals that don't have an official standard, and when there isn't a spec for mating crimp terminals from company A to PCB headers from company B, even if they physically fit.The 12VHPWR connector I think you're referring to is a decent example, although there is at least a spec for that from PCI-SIG. I don't think they spec all the way down to the exact shape of the terminal contacts though, so they leaves some room for interpretation by the manufacturer to either get it right...or wrong.Quote from: TheUnnamedNewbie on May 04, 2023, 08:50:39 amThat's a good point on standards. I suspect the PC industry mostly falls in to "connectors that are copied and not protected or even officially licensed". I guess there is enough safety margin built-in to the current ratings, and the connector manufacturers aren't stupid, so everything works well enough together.Quote from: tooki on May 04, 2023, 12:33:29 pmI've asked Molex once about mating HCS and non-HCS terminals, all from Molex, and they would only say "We only recommend our parts mate with the listed mates in the mates with/use with section on the product page." and "We can only promote our products mate with the specified Molex mate for quality purposes. I cannot speak to any other products."I'm thinking, if I want to connect an ATX power supply to something, there's no way I'm going to know if the PSU manufacturer used HCS or non-HCS crimp terminals. So I figure I'd better use HCS headers and hope that mating HCS and non-HCS just means the connection is rated at the non-HCS current level, not 1/2 the non-HCS level or something even worse than just the weakest link.

author: tooki
author_rank: Super Contributor
timestamp: May 04, 2023, 06:25:53 pm
content: Quote from: tinfever on May 04, 2023, 05:41:38 pmSo you asked one manufacturer, got one answer, and from that extrapolated that that is what all manufacturers do, thus invalidating my claim that some datasheets talk about mating with competitors’ products. Got it. 🙄Here’s an excerpt from aTE Connectivity power connector catalog:Quote

author: langwadt
author_rank: Super Contributor
timestamp: May 04, 2023, 08:09:49 pm
content: Quote from: tooki on May 04, 2023, 06:25:53 pmand how could Molex possibly speak on behalf of other manufacturers

author: tooki
author_rank: Super Contributor
timestamp: May 05, 2023, 01:11:45 pm
content: Quote from: tinfever on May 04, 2023, 05:41:38 pmFYI, I checked, and it looks like the HCS headers and contacts differ only in material ("high performance copper alloy", TE calls it) as opposed to the brass or phosphor bronze in the standard parts. They're expressly designed to use the same application tooling, so that means that every dimension is identical. (In particular, even minute differences in materials would require different crimp tooling, so their express claim that existing tooling is used means that it must be identical.) Thus, the only thing that makes the headers capable of higher currents is the copper alloy having lower specific resistance. The crimp contacts, especially the female ones, could in theory use slightly different internal mating surface geometry, but I kinda doubt it, since the male crimp pins are absolutely identical except for material.I can't see any way in which intermating HCS and standard could result inlowercurrent capacity than standard.

author: tinfever
author_rank: Regular Contributor
timestamp: May 05, 2023, 06:58:12 pm
content: QuoteOkay, that's fair. I've extrapolated too far from the unhelpful answer of one manufacturer. I didn't mean to imply your claim was invalid.Quote from: langwadt on May 04, 2023, 08:09:49 pmThat's kind of my point. It would be a lot to expect each manufacturer to create a big compatibility matrix between their connector and everyone else's similarly shaped connector. And yet, industries seem to rely on these different connectors mating to each other without each combination having been specifically tested. In scenarios where there is no precisely dimensioned standard for the contacts, it seems like an enormous amount of weight is being put on the words "or equivalent"From the Intel ATX PSU Spec:5.2.2.1Main Power Connector – REQUIREDConnector: Molex* Housing: 24 Pin Molex Mini-Fit Jr. PN# 39-01-2240or equivalent.Contact: Molex 44476-1112 (HCS)or equivalent(Mating motherboard connector isMolex 44206-0007or equivalent).18 AWG is suggested for all wires except for the +3.3 V supply and sense return wirescombined into pin 13 (22 AWG).I expect very few manufacturers of PSUs or computer components are actually using Molex brand parts. And yet it all works! Copies of copies of copies, all equivalent enough I guess.Quote from: tooki on May 05, 2023, 01:11:45 pmI hadn't thought about it that way. Thank you.

author: tinfever
author_rank: Regular Contributor
timestamp: May 05, 2023, 07:34:54 pm
content: Interestingly, it looks like assumed compatibility between manufacturers doesn't always work out:PV connector mating and intermatability in NEC 2020https://www.solarpowerworldonline.com/2020/09/pv-connector-compatibility-rules-are-likely-coming-to-the-national-electrical-code/"As part of a technical assessment of solar project risk, TÜV Rheinland evaluated different PV module failure modes according to severity of effects, likelihood of occurrence and detectability. According to the results of this Failure Modes and Effects Analysis (FMEA), failures associated with dissimilar connectors represent the single greatest risk to PV system performance and safety. Walmart’s now-settled lawsuit against Tesla, which hinged in part on roof fires and incompatible module connectors, illustrates high stakes associated with dissimilar connectors."

author: tooki
author_rank: Super Contributor
timestamp: May 05, 2023, 11:09:17 pm
content: Quote from: tinfever on May 05, 2023, 07:34:54 pmThis is true, but also a bit of a special case, in that they’re used at quite high currents (up to 95A for the leading connector, the MC4), must withstand high voltages (up to 1500V for MC4), and be weatherproof for decades of outdoor use. That is a lot to ask of a connector.Unsurprisingly, in addition to compatible connectors from big-name connector manufacturers, there’s a huge number of cheap fake MC4 connectors that simply aren’t made to the same manufacturing tolerances as the originals or big-name clones. They may be off dimensionally, the materials may be different, etc.* And the worst thing is when they’re passed off as the genuine article, causing people to unwittingly mix brands. (Not that the cheap fakes perform as well even when mated with themselves.)Additionally, when the wrong tooling is used for assembly (be it cheap tools with cheap connectors, cheap tools with genuine connectors, genuine tools with counterfeit connectors, or genuine tools from one good brand with genuine connectors of a different good brand), that can cause problems. The only connectors I’m aware of where tool and contact compatibility are completely guaranteed regardless of tool manufacturer and contact manufacturer are the mil-spec connectors, because the US military designed the specs and any manufacturer that wants to sell to the military (and aerospace, which also uses them commonly) has to follow those specs.**This article covers a lot of the PV connector issues in more detail.https://www.pvel.com/wp-content/uploads/PVEL-HelioVolta-Ultimate-Safety-Guide-for-Solar-PV-Connectors-Feb-2022.pdfThese pitfalls do apply to small, low voltage connectors like Mini-Fit Jr, but the stakes are far, far lower, since the environment is much less demanding, and they’re not as likely to actually remain in use for 25 years.*The genuine MC4 connector is from Stäubli, which also makes some of the very best, possiblythebest, banana plugs on the market. And unsurprisingly, there are plenty of clones of Stäubli’s signature lantern-style (“lamella”) plugs. Some are good, but some are awful. They look similar at first glance, but for example, on some the plating of the parts is not as conductive, which is a big issue with lantern plugs, where the lantern is free to rotate. On some, the lantern is too loose on the plug shaft, also reducing conductivity. On some, the material of the lantern is bad, so that after a few insertions, it loses compliance (doesn’t spring back as much) and then fits into jacks loosely, reducing conductivity. In contrast, I have encountered well-used genuine Stäubli plugs that are older than I am, and they still perform like new. I’ve literally never seen one wear out.**I wonder if instead of the NEC requiring installers to ensure they don’t mix connector types, if maybe the NEC shouldn’t simply create a manufacturer-agnostic “NEC spec” that any connector companies that want to sell in USA have to follow, just like the mil-spec connectors. Unified tooling, unified part numbers and specs, etc.