Recall: Power Outlet May Cause Charging Cable to Overheat (20-24) APB6 - December 13, 2023

[whitex]

will I get my $1 bet winnings from my local service manager - he said they'd never do it…LOL

Have him sign it, laminate it, bring out any time the service manager has an argument with you.

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[daveo4EV]

4 for NEMA 14-50 cable.

on both my NEMA 14-50 PMCC cables the 4th wire is _NOT_ wires up inside the cable - only the 3 AAC power lines are actually present as connectors in the cable assembly.

 

[whitex]

on both my NEMA 14-50 PMCC cables the 4th wire is _NOT_ wires up inside the cable - only the 3 AAC power lines are actually present as connectors in the cable assembly.

I stand corrected. NEMA 14-50 does't have the 4th pin, 120V does. This is the NEMA 5-15 cable:

PS> I cheated a little bit, the above is from the Audi PMC+, it was easier to get to in the garage where I shoved them, as I got it more recently with my wife's Audi.

 

[Tooney]

Original post edited to add more detailed information from Porsche recall report, including more about the chronology, 110 reports from the field, and part numbers of the 4 cables involved.

TL;DR: it's all due to those "lower quality receptacles" ....

 

[daveo4EV]

ROFL -

In Dec. 2020 Porsche became aware

Porsche was aware of this as early as July of 2020 - and I can prove it.

 

[DougFrisk]

The cable has 6 signaling pins besides 4 power and 1 ground. Only 3 are used for 120V cable, 4 for NEMA 14-50 cable. Not sure what the encoding on these, but they are more than likely there to signal the current capability. It's possible the designer had some forethought (perhaps from studying Tesla EVSE's) to include an input for a temperature sensor. Alternatively, maybe they just have the cable change its signaled current rating, so NEMA 14-50 drops to 30A when sensor reaches some threshold temperature, and to 15A when it reaches the next one, and signals cable not plugged in when about to reach melting temperature? Whatever the capability they use, it must already be in current firmware, since they've showed us they cannot update PMC+ firmware.

My assumption has been that the pins are used essentially the same way DIP switches would be used. Five pins, one ground and four for selection, would give you sixteen possible associated amperages allowing for sixteen different plug ends with was many charging levels.

 

[Tooney]

I looked up the descriptions of the cables listed in Porsche recall report:
7PP971678EA: NEMA 6-30 24 AMP
7PP971678EB: NEMA 14-30 24 AMP
7PP971678EC: NEMA 6-50 40 AMP
7PP971678ED: NEMA 14-50 40 AMP

https://www.boutiqueporschepoitiers.fr/pieces/taycan/9J1/2022/251-370/

 

[whitex]

My assumption has been that the pins are used essentially the same way DIP switches would be used. Five pins, one ground and four for selection, would give you sixteen possible associated amperages allowing for sixteen different plug ends with was many charging levels.

They could also be resistance values (like J1772 cable ratings). It might also allow for temperature sensing through resistance values.

 

[daveo4EV]

I looked up the descriptions of the cables listed in Porsche recall report:
7PP971678EA: NEMA 6-30 24 AMP
7PP971678EB: NEMA 14-30 24 AMP
7PP971678EC: NEMA 6-50 40 AMP
7PP971678ED: NEMA 14-50 40 AMP

https://www.boutiqueporschepoitiers.fr/pieces/taycan/9J1/2022/251-370/

hmm m- the NEMA 30 cables don't have a thermal problem - seems to me Porsche still lacks a full understanding of their defects in this case.

 

[whitex]

hmm m- the NEMA 30 cables don't have a thermal problem - seems to me Porsche still lacks a full understanding of their defects in this case.

I don't have a NEMA x-30 cable to see. Are you sure those don't use even thinner wires?

 

[amelen]

Sounds like exactly what happened to me (and so many others), ie:

https://www.taycanforum.com/forum/threads/warranty-on-the-porsche-charger.16905/

 

[daveo4EV]

I don't have a NEMA x-30 cable to see. Are you sure those don't use even thinner wires?

AWG 10 is the wire used in the NEMA 14-30/6-30 power supply cables - expected thermal rise is much lower for 24 amps of current - basically it's no different than running the NEMA 14-50/6-50 cables @ 32 amps or less - there is no thermal issue with Porsche's supply cables at 32 amps or less.

 

[DougFrisk]

AWG 10 is the wire used in the NEMA 14-30/6-30 power supply cables - expected thermal rise is much lower for 24 amps of current - basically it's no different than running the NEMA 14-50/6-50 cables @ 32 amps or less - there is no thermal issue with Porsche's supply cables at 32 amps or less.

#10 wire is appropriate for most 30 amp wiring runs at 60 degrees C, that's 30 amps of continuous current draw not a 30 amp breaker. #10 wire can be used for 40 amp runs if the wire (and connectors and boxes and...) are rated at 90 degrees C, that's 194 degrees F. Note that 40 amps is literally the maximum load possible for the highest temperature rated #10 copper wire.

Porsche uses a wire that is technically appropriate, but has zero margin for safety. It also assumes that the socket it's plugged into and the box the socket is in are rated for 90 degrees C. That's typical in a commercial installation, but not in a residential installation in the US so it was a bad assumption.

 

[daveo4EV]

#10 wire is appropriate for most 30 amp wiring runs at 60 degrees C, that's 30 amps of continuous current draw not a 30 amp breaker. #10 wire can be used for 40 amp runs if the wire (and connectors and boxes and...) are rated at 90 degrees C, that's 194 degrees F. Note that 40 amps is literally the maximum load possible for the highest temperature rated #10 copper wire.

Porsche uses a wire that is technically appropriate, but has zero margin for safety. It also assumes that the socket it's plugged into and the box the socket is in are rated for 90 degrees C. That's typical in a commercial installation, but not in a residential installation in the US so it was a bad assumption.

agreed- what is unclear from the recall is has Porsche changed the wire gauge in the replacement power supply cables - or have they just added a thermal sensor and kept the #10 AWG wire…

I'm hoping for sensor + 8 (or 6) AWG wire
but I'm pretty sure it will be just a "sensor" and they are going to cheap out on the wire…

 

[DougFrisk]

agreed- what is unclear from the recall is has Porsche changed the wire gauge in the replacement power supply cables - or have they just added a thermal sensor and kept the #10 AWG wire…

I'm hoping for sensor + 8 (or 6) AWG wire
but I'm pretty sure it will be just a "sensor" and they are going to cheap out on the wire…

The wire would likely be cheaper. At retail prices, THHN goes for about $0.50/foot at 10 gauge and $1 a foot at 6 gauge. That would be about $1.50 additional per unit. A thermal sensor and switch would no doubt be more expensive.

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