Most of this discussion is either over my head or out of my wheelhouse. That
said:
Would it work to have a locking connector combined with a tether activated
power disconnect and lock release?
I'm envisioning a spring-wound reel of cord that trips a disconnect and release
in a safe and non-destrucive way before the cord end and cable ends reach their
limits.
On September 23, 2024 5:57:04 p.m. CST, "(-Phil-) via EV" <ev@lists.evdl.org>
wrote:
>I have personally tested a number of CCS DCFCs, and NONE of them
>de-energize fast enough to avoid arcing when Pilot and/or Proximity is
>de-asserted. It's a tall ask to have a DCFC putting out 500 amps and 800
>volts to get it to zero volts in a few milliseconds. This is why there is
>a latch.
>
>Disconnecting AC under load is NOT THE SAME. There is zero crossing 120
>times a second that will help extinguish an arc, and current is over a
>magnitude less. DCFC has way more current, and high voltages connected
>directly to a current source that can provide tens of thousands of amps of
>fault current!
>
>On Mon, Sep 23, 2024 at 4:45 PM Bill Dube via EV <ev@lists.evdl.org> wrote:
>
>> I should note that the connector is designed so that the pilot wire
>> (communication wire) is the very first to disconnect. If the regulation
>> is followed correctly, this should automatically de-energize the entire
>> circuit, before the connector comes apart completely.
>>
>> >>>>> Locking connector rant <<<
>>
>> From the inception of Article 625 in the NEC, I have disdained the
>> requirement that the connector(s) be of the locking type.
>>
>> It makes _zero_ sense to have a locking connector on a object that is
>> mobile. If the vehicle moves somehow, the plug should simply disconnect
>> without indecent or damage. (The vehicle parking brake is not set
>> correctly. The vehicle is towed. The vehicle is accidentally hit by
>> another vehicle. The vehicle is somehow placed in drive. etc....)
>>
>> Because the connector is locking, ("to prevent accidental disconnection"
>> which is _not_ a life-threatening hazard,) if the connector is strained
>> beyond its breaking point, either the cable conductors are dislodged and
>> exposed, or the connector housing in the vehicle is dislodged exposing
>> live conductors, or the cord is pulled out to the wall box exposing live
>> conductors. If plug were to simply disconnect, like on a vacuum cleaner,
>> or on an RV, then these hazards would be non-existent.
>>
>> As the regulation is now implemented, you have to have (expensive and
>> troublesome) strain sensors on both the wall box and the vehicle
>> connector housing to (hopefully) de-energize the live conductors before
>> they become exposed.
>>
>> The mandatory requirement for a locking connector should be dropped, or
>> at least made optional.
>>
>> >>>> Soap box mode OFF <<< 🙂
>>
>> Bill D.
>>
>> On 9/24/2024 10:53 AM, (-Phil-) via EV wrote:
>> > I have discussed this here before, but neither the Lectron or the A2Z
>> have
>> > a proper mechanical interlock, meaning you can literally rip out the NACS
>> > cable while HV is still present, which could result in an arc flashover
>> > between the terminals with full pack voltage. This could generate over a
>> > thousand amps of fault current and even completely destroy your EV!
>> >
>> > The CCS standard requires a mechanical interlock that prevents the
>> removal
>> > of the CCS whip while HV is present. This is enforced by a motorized
>> latch
>> > in the car. But there is no mechanical interlock on either of these
>> > adapters, which means the connector could be removed under load! So if
>> > you ever use it, please supervise it the whole time (do not leave
>> > unattended!) and do not disconnect the NACS able from the adapter until
>> the
>> > car unlatches the adapter from the inlet, only then is it safe to remove
>> > the NACS cable.
>> >
>> > On Mon, Sep 23, 2024 at 1:53 PM Jack Hill <jackh...@jackhill.us> wrote:
>> >
>> >> I'm one of the people who bought a Lectron adapter (although other than
>> >> testing I may never have to use it. We'll see how long CCS1 sticks
>> around
>> >> I guess). Can you expand on why they're dangerous? I did read the
>> report,
>> >> and can't argue with the recommendations, but didn't see it call out
>> >> what's specifically wrong with the Lectron adapter. Lectron's AC J3400
>> >> adapter has seen years of real world use and held up fine.
>> >>
>> >> I'm happy to see standards. I'm kind of shocked that J3400 is being
>> >> rolled out without them. It seems to me like the right order would be to
>> >> do the standards first, and then a roll out (we have CCS and J1772 in
>> the
>> >> meantime).
>> >>
>> >>> Thanks for posting this, Rush!
>> >> Indeed, thank you!
>> >>
>> >> Best,
>> >> Jack
>> >>
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