Chiming in here a little bit: On a recent task I was able to participate here at work, we acquire as many of the most popular CCS/NACS, NACS/CCS adapters and performed several electrical and thermal evaluations in order to support the UL 2251, UL 2252, SAE J3400 & J3400/1 standards committees to help them by providing more data safety related.... NONE of these adapters complied with all the thermal/ safety requirements. (this work was conducted between Q4-2024 and Q2-2025).
https://docs.nrel.gov/docs/fy25osti/94107.pdf We purposely built a bench that was able to test the adapter's continuous and max currents at nominal and extreme temperatures, simulating hot weather environments (such in AZ or NV) and introducing high-current (with low-voltage in order to make the testing bench safe to operate). We also designed and built a J3400 (NACS) reference device, since no one had done this before, which we used as our reference point for all of the evaluations and for UL. Long story short, none of the adapters complied with all of the safety thermal requirements as established on previously mentioned standards. Particularly J3400 and UL 2251 introduces two new thermal safety features, one is called Thermal Foldback (also known as Thermal Warning) via the Proximity Pilot line, which indicates both the EV and the EVSE that temperatures at the EV inelt, at the EVSE connector, or in this case within the adapter itself; is rising very quick and an immediate action needs to be taken by the EVSE first which consists of reducing the actual current by half or at least to 100 Amps. The session continues but at a degraded state. The second feature is known as Thermal Shutdown, which is a second higher temperature point that immediately stops and aborts the charging session since temperatures are at dangerous levels. We noticed most of the cheap adapters (mostly from Amazon) did not include any or some of these features, did not properly recover after cooling down or did it incorrectly. We also noticed that even with liquid cooling EVSE cables, sometimes and because of the design of these adapters (temp. sensors not ideally located), the adapter pins and sockets could get really hot and the temperature sensors not being able to catch these changes until it's quite late (some temperature sensors were not even touching the pins/busbars). Not in this report, but we even found some adapters being sold by auto OEMs (yes from the dealership with your new EV) where the adapter was labeled as 1000V capable, but by looking at its mechanical construction (creepage and clearance) it was using the 500V old designs. So, as a way of conclusion and from my own perspective: 1. First and most important: Do not use any adapter at all if you can charge somewhere else, even if it will cost you a bit more or take a bit more time. It is not worth the risk of your safety and your car's worth. 2. Only use it in really urgent situations and only if you have no other choice. If you know you have a cheap adapter (may not have UL 2252 approval) and want to minimize the risk of overheating, arcing, then; 1. Use the slowest power DCFC stations as possible (choose the 50-150kW over the 250-350kW even if your EV can take it), 2. Do NOT pre-condition your battery, this will reduce the peak-current the adapter would experience. Don't worry, your EV will start pre-conditioning your battery as soon as you plug in, but by the time your battery is warm enough to increase current, your SOC should be high enough to limit the max current that could overheat your adapter. 3. Always keep your adapter 'yours', never lend it, never drop it (otherwise might be compromised), always keep it protected in a sealed ziplock bag, +soft rag, etc in a dry, free of moisture, sand, dust, etc. Always inspect the pins and sockets for debris/mold, look for plastic cracks or holes, etc. both on your adapter and the EVSE connector you are plugging in. 4. My only brand for adapter either CCS or NACS I can recommend for now is Amphenol, only because they've been part of the ChargeX consortium and perfectly know and helped shape the UL and SAE standards mentioned above. Lectron and A2Z are ok too. No other ones I can recommend for now. 5. If you bought one of these $50 to 100 bucks cheap adapters anywhere (specially on Amazon) that is more than one year old, you'd better toss it and get a new one that has the UL 2251/2252 marking ONLY. The more recent, the better chances it complies with the most recent UL updates and testings. 6. Similarly, if you bought one of these that claims to do 'Both' AC and DC, get rid of that immediately (destroy it, so no one can use it) since these are a safety hazard with higher risk of electric shock. 7. Similarly, discard it if your adapter has no 'pin caps' (these protective plastic caps in front of the metal exposed pins) that prevents your fingers from touching the metal parts of the adapter/connector pins. 8. Never buy an adapter and/or an extension cord, no matter what the brand is, if the part does not include safe ways to stop the charge session (only possible via the Control Pilot or Proximity Pilot signals) in order to safely disconnect. If the adapter allows you to disconnect while being energized (hot) that is a huge No No and safety concern. Unless you are 100% aware of it and/or you're the only user of it (no kids/family operating it). Also, related to some adapters that allow you to 'disconnect' while under load, we also ordered some of these 'NACS extension cords' for AC charging, and found that you could disconnect while under-load and that the extension had absolutely no way to electrically tell the EV/EVSE of attempting to disconnect, so it would let you unplug while energized. While AC adapters and extension cords are less riskier, still you can experience arc blasting, burns, damage to your vehicle's charging inlet port (permanent damage to the pins), etc. But the risk increases on to 100x or more on DC systems since while the session is still active, it is not only the power being provided by the charging station, but also all of the huge amount of instant power from the battery from your EV, all at once at your EV inlet port/adapter since that is in parallel during the DCFC session. This video shows a perfect example of how a DCFC session can quickly go wrong (arc blast/explosion) with a cheap adapter: https://youtu.be/yj-auGkIRSs?si=Y0-2iHkPqlG7Y-2L Then, here's another example how some careless businesses supposedly 'design' adapters (yes, as per UL standard, an extension cord is also considered an adapter) that should NOT be in the market for being extremely unsafe: https://youtu.be/jPp3UOEW_y8?si=ztiNQn2HuoMfN8rg Hope this helps Marco Gaxiola On Sat, May 16, 2026 at 8:15 PM (-Phil-) via EV <[email protected]> wrote: > The Tesla manufactured adapters have a (required) mechanical interlock. > You cannot unlatch the NACS side until the adapter is removed from the EV. > Likewise the Tesla CCS to NACS also has this interlock. > > Only an improperly designed adapter can be removed from the cable while > still attached to the EV. Again; this is not optional, it's just the cheap > adapter makers don't care. > > On Sat, May 16, 2026 at 7:09 PM jim--- via EV <[email protected]> wrote: > > > Standard advise on the Ford Lightning Forum is to NOT use any of the > cheap > > adapters - period. > > > > One thing Bill mentioned is that the pilot signal is the first to > > disconnect with the connector is pulled apart, but on all the good > adapters > > (and charging cables), the pilot signal is also disconnected as soon as > the > > release button is pressed. Therefore initiating the shutdown as soon as > > the mechanical release is pressed. And at least some (maybe most) EVs do > > lock the connection until the vehicle is satisfied that power is off. > That > > does NOT prevent disconnecting the NACS plug from the NACS to CCS-1 > adapter. > > > > Personally with my Lightning, I always stop the session either with the > > stop button next to the charge inlet, or the stop button in the Ford App, > > or the stop button in the charging network App. Then verify either with > > the Charge dispenser or the vehicle display that charging has stopped > > before I pull the connector out. > > > > Jim Walls > > > > > > > > -----Original Message----- > > From: "(-Phil-) via EV" <[email protected]> > > Sent: Saturday, May 16, 2026 18:28 > > To: "Electric Vehicle Discussion List" <[email protected]> > > Cc: "(-Phil-)" <[email protected]> > > Subject: Re: [EVDL] Amazon.com: Eioehtl Upgraded NACS to CCS Adapter > > > > It takes the power electronics in a near half megawatt system to spool > > down, and contactors to open. All the OEM adapters have the required > > mechanical interlocks that PREVENT you from unlatching until the vehicle > > knows the system is safe. > > > > It's also not unheard of for contactors to weld if asked to open under > > load, then you have full pack there at the inlet, even if the power > > electronics have shut off. > > > > The standard requires it, UL requires it, common-sense requires it, and > > it's not that hard to implement. It's a carefully placed pin and spring, > > that's it. > > > > On Sat, May 16, 2026 at 6:22 PM Bill Dube via EV <[email protected]> > > wrote: > > > > > It _appears_ to lock onto both input and output connectors. > > > > > > As I recall, the pilot wire is the first to disconnect when the > > > connector parts from the receptacle. > > > When the pilot signal is cut off, this signals the charger to shut off > > > immediately. Thus, no arc, at least in theory. > > > There is all sorts of belt and suspenders safety stuff built-in to EV > > > charging. > > > > > > Additionally, I believe that OEM EV's simply won't move when they are > > > plugged in, aside from being physically towed away. > > > Again, the belt and suspenders safety stuff... > > > > > > Bill D. > > > > > > On 17/05/2026 5:44 am, (-Phil-) via EV wrote: > > > > Almost none of these low-cost adapters have the technically required > > > > mechanical interlock. This means you can rip out the cable while > > > high-amp > > > > charging is occurring and this could cause an arc flashover which is > > > > basically shorting out your battery pack! NEVER attempt to unplug > one > > > > until you stop the charging somehow. > > > > > > > > The Tesla made OEM adapters have a mechanical interlock that prevents > > you > > > > from disconnecting until the port is unlocked only after the system > > > > determines there's no voltage present anymore, this is how it should > > be! > > > > > > > > On Sat, May 16, 2026 at 10:04 AM Mark Hanson via EV < > [email protected] > > > > > > > wrote: > > > > > > > >> Hi folks > > > >> A friend sent me this $50 adapter that got good reviews. Although I > > > bought > > > >> a $200 GM Bolt adapter last year, I was curious if anyone has > > experience > > > >> with direct pulling the cord while charging, safety it claims incase > > > >> someone else borrows the car and forgets to turn off the fast > charger > > > via > > > >> the dash. > > > >> Best regards mark > > > >> > > > > > > https://www.amazon.com/500A-1000V-NACS-Adapter-Superchargers/dp/B0DTDZP3HJ > > > >> > > > >> Sent from my iPhone > > > >> _______________________________________________ > > > >> Address messages to [email protected] > > > >> No other addresses in TO and CC fields > > > >> HELP: http://www.evdl.org/help/ > > > >> OT: If you use an Android device, please read > > > https://keepandroidopen.org/ > > > >> > > > > -------------- next part -------------- > > > > An HTML attachment was scrubbed... > > > > URL: < > > > > > > http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20260516/8e18c220/attachment.htm > > > > > > > > _______________________________________________ > > > > Address messages to [email protected] > > > > No other addresses in TO and CC fields > > > > HELP: http://www.evdl.org/help/ > > > > OT: If you use an Android device, please read > > > https://keepandroidopen.org/ > > > > > > > > > _______________________________________________ > > > Address messages to [email protected] > > > No other addresses in TO and CC fields > > > HELP: http://www.evdl.org/help/ > > > OT: If you use an Android device, please read > > https://keepandroidopen.org/ > > > > > -------------- next part -------------- > > An HTML attachment was scrubbed... > > URL: < > > > http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20260516/ac429906/attachment.htm > > > > > _______________________________________________ > > Address messages to [email protected] > > No other addresses in TO and CC fields > > HELP: http://www.evdl.org/help/ > > OT: If you use an Android device, please read > https://keepandroidopen.org/ > > > > > > _______________________________________________ > > Address messages to [email protected] > > No other addresses in TO and CC fields > > HELP: http://www.evdl.org/help/ > > OT: If you use an Android device, please read > https://keepandroidopen.org/ > > > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: < > http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20260516/a527a3de/attachment.htm > > > _______________________________________________ > Address messages to [email protected] > No other addresses in TO and CC fields > HELP: http://www.evdl.org/help/ > OT: If you use an Android device, please read https://keepandroidopen.org/ > -- Marco Gaxiola -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20260517/fba06cdd/attachment.htm> _______________________________________________ Address messages to [email protected] No other addresses in TO and CC fields HELP: http://www.evdl.org/help/ OT: If you use an Android device, please read https://keepandroidopen.org/
